M. Eng., Kyoto University

Dr. Eng, Kyoto University

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Manufacturing and production engineering

Apr. 2020 - Mar. 2022
vice president

01 Apr. 2013
電気通信大学 大学院情報理工学研究科, 教授

01 Apr. 2010 - 31 Mar. 2013
電気通信大学 大学院情報理工学研究科, 准教授

01 Apr. 2007 - 31 Mar. 2010
電気通信大学 電気通信学部, 准教授

Jan. 2003 - 31 Mar. 2007
The University of Electro-Communications, Assoc, Prof.

Apr. 1988 - Mar. 1990
Kyoto University, Graduate School, Division of Engineering, Precision Engineering, Japan

Mar. 1988
Kyoto University, Faculty of Engineering, Precision Engineering

Apr. 1980 - Mar. 1983
Ritsumeikan Senior High School, Japan

Apr. 2022 - Present
庶務理事（国際交流，産学連携）, 日本塑性加工学会

Apr. 2022 - Present
創形創質部会 副部会長, 日本鉄鋼協会

Apr. 2018 - Present
チューブフォーミング分科会 主査, 日本塑性加工学会

Apr. 2005 - Present
プログラム編集委員, 日本鉄鋼協会

Nov. 2021 - Nov. 2022
Chair of TUBEHYDRO2022 (国際会議TUBEHYDRO 2022), TUBEHYDRO2022

Apr. 2018 - Mar. 2022
研究振興助成審査委員, 日本鉄鋼協会

Apr. 2016 - Mar. 2018
チューブフォーミング分科会 庶務幹事, 日本塑性加工学会

Apr. 2003 - Mar. 2017
伸線技術分科会 会計幹事（2004年10月-2006年3月を除く）, 日本塑性加工学会

Apr. 2005 - Mar. 2016
ロールフォーミング分科会 運営委員, 日本塑性加工学会

Apr. 2003 - Mar. 2016
チューブフォーミング分科会 運営委員, 日本塑性加工学会

Apr. 2012 - Mar. 2014
庶務理事（国際交流）, 日本塑性加工学会

Apr. 2005 - Mar. 2014
企画委員, 軽金属学会

Apr. 2009 - Mar. 2013
50周年実行委員, 日本塑性加工学会

Apr. 2008
Corresponding Member, Interviewer, 英国機械技術者協会, Society

Apr. 2003 - Mar. 2005
ふぇらむ会報委員会委員, 日本鉄鋼協会, Society

Apr. 2004
チューブフォーミング分科会 委員, 日本塑性加工学会, Society

May 2003
伸線技術分科会運営委員, 日本塑性加工学会, Society

Apr. 1998 - Mar. 1999
棒鋼・線材圧延３次元ＦＥＭ解析システムのﾌｫﾛｰｱｯﾌﾟ委員会委員, 日本鉄鋼協会, Society

Apr. 1996 - Mar. 1998
棒鋼・線材圧延３次元ＦＥＭ解析システムの開発研究会委員, 日本鉄鋼協会, Society

Aug. 2023
THE INTERNATIONAL ACADEMY FOR PRODUCTION ENGINEERING
Fellow of CIRP, Takashi Kuboki

Jun. 2023
The Japan Society for Technology of Plasticity
Effect of Inclusions on Internal Fracture in Skew Rolling
Paper award, Koji YAMANE;Kazuhiro SHIMODA;Koichi KURODA;Shohei KAJIKAWA;Takashi KUBOKI

Jun. 2017
Japan society of technology for plasticity
レーザ切断材の曲げ加工時に発生する長手そり抑制技術の開発
日本塑性加工学会賞 技術開発賞（一般）, Yingjun Jin;Takahiro Shibata;Nobuto Miyashita;Hitoshi Omata;He Huang
Japan society, Japan

May 2016
公益財団法人 天田財団
傾き自在な工具を用いた薄板・箔のマイクロ逐次打点成形
天田財団 第14回助成研究成果発表会 優秀賞, 久保木 孝
Publisher

Apr. 2016
日本塑性加工学会 東京・南関東支部
レーザ切断材の曲げ加工時に発生する長そり抑制技術の開発
日本塑性加工学会 東京・南関東支部 技術開発賞, 金 英俊;柴田 隆浩;宮下 信人;小俣 均;黄 河;久保木 孝
Japan society, Japan

May 2004
日本塑性加工学会論文賞「冷間据込み時の割れ発生予測」

May 2003
United States of America
The Silver Certificate Award from Wire Association International
United States

May 2002
Japan
日本塑性加工学会論文賞｢ダイレスＵベンド法の理論解析｣
Japan

May 2001
Japan
日本塑性加工学会新進賞
Japan

Feb. 2001
Japan
線材製品協会懸賞論文１等賞｢抽伸加工材の残留応力低減技術に関する研究｣
Japan

Oct. 1991
Japan
Medal for Outstanding Paper from JSME:"Estimation of transmission error of cylindrical involute gears by tooth contact pattern"
Japan

Deep Container Fabrication by Forging with High- and Low-Density Wood
Hinako Uejima; Takashi Kuboki; Soichi Tanaka; Shohei Kajikawa
Journal of Manufacturing and Materials Processing, MDPI AG, 8, 1, 30-30, 06 Feb. 2024, This paper presents a method for applying forging to high-density wood. A cylindrical container was formed using a closed die, and the appropriate conditions for temperature and punch length were evaluated. Ulin, which is a high-density wood, and Japanese cedar, which is a low-density wood and widely used in Japan, were used as test materials. The pressing directions were longitudinal and radial based on wood fiber orientation, and the shape and density of the resulting containers were evaluated. In the case of ulin, cracks decreased by increasing the temperature, while temperature had little effect on Japanese cedar. Containers without cracks were successfully formed by using a punch of appropriate length. The density of the containers was uniform in the punch length l = 20 and 40 mm in the L-directional pressing and l = 20 mm in the R-directional pressing when using ulin, with an average density of 1.34 g/cm3. This result indicates the forging ability of ulin is high compared to that of commonly used low-density woods. In summary, this paper investigated the appropriate parameters for forging with ulin. As a result, products of more uniform density than products made by cutting were obtained.
Scientific journal, English

Effect of Initial Cross-Sectional Shape on Bent Shape in “Bending and Compression Method” for Forming In-Plane Bent Sheet Metal
Tsuyoshi Muraoka; Yusuke Okude; Shohei Kajikawa; Takashi Kuboki
Corresponding, Lecture Notes in Mechanical Engineering, Springer Nature Switzerland, 307-316, 20 Sep. 2023, Peer-reviwed
International conference proceedings, English

Stress Relief for Crack Prevention by Adding Holes to V-Bending Die
Ryunosuke Yakuno; Hiroki Suwa; Kazuhito Takahashi; Shohei Kajikawa; Yasunori Yusa; Takashi Kuboki
Corresponding, Lecture Notes in Mechanical Engineering, Springer Nature Switzerland, 348-358, 20 Sep. 2023
In book

Effect of Material on Strain Direction in Tube Expansion Drawing Process
Shiliang Zhang; Takashi Kuboki; Masayoshi Akiyama; Shohei Kajikawa
Lecture Notes in Mechanical Engineering, Springer Nature Switzerland, 594-602, 23 Aug. 2023, Peer-reviwed
In book

Square Tube Fabrication by Expansion Drawing of Circular Tube
Shohei Kajikawa; Yusuke Kato; Shiliang Zhang; Takashi Kuboki; Masayoshi Akiyama
Lecture Notes in Mechanical Engineering, Springer Nature Switzerland, 612-621, 23 Aug. 2023, Peer-reviwed
In book

Effect of Plug Angle on Formability in Tube Drawing with Diameter Expansion
Shohei KAJIKAWA; Masato ARAKI; Masato WATANABE; Hisatoshi TSUEOKA; Akinori TSUCHIYA; Takashi KUBOKI
Last, Journal of the Japan Society for Technology of Plasticity, The Japan Society for Technology and Plasticity, 64, 750, 123-128, Jul. 2023, Peer-reviwed
Scientific journal, Japanese

Parallel parametric analysis approach based on an s-version FEM for fracture mechanics analysis in designing hole positions
Hiroki SUWA; Yasunori YUSA; Takashi KUBOKI
Mechanical Engineering Journal, Japan Society of Mechanical Engineers, 10, 3, 22-00462-00462, Jun. 2023
Scientific journal, English

Effect of Roller Axial Position and Thickness on a Twisted Angle in the Twist Rolling of Aluminum Alloy 1050 Sheet Metal
Avanish Kumar; Shohei Kajikawa; Takahiro Makiyama; Takashi Kuboki
Corresponding, Metals, MDPI AG, 13, 2, 383-383, 13 Feb. 2023, Peer-reviwed, This paper proposes a new rolling method called “twist rolling” that can continuously form a twisted shape by using taper rollers. The twisted shape of metal sheets is widely used in industrial products such as turbine blades and propellers. Such a shape is normally formed by casting or machining, but there are problems with low efficiency regarding the productivity and yield ratio. Forging processes have also been proposed, but they have problems with the surface property. The present study focuses on rolling to efficiently form a continuously twisted shape. The effect of the axial position of the taper rollers and skew angle on the average specific twisted angle were investigated by experiments and finite element analysis. The relationship between the thickness of sheet metal and the average specific twisted angle was also investigated. The average specific twisted angle decreased as the axial position increased. When the skew angle was smaller and the sheet metal thicker, the average specific twisted angle increased more. Twist rolling can form various twist angles by changing such parameters.
Scientific journal

Effects of Plug Angle on Formability in Tube Drawing with Diameter Expansion
ShiLiang ZHANG; Hikaru KAWAGUCHI; Takashi KUBOKI; Isamu AKASAKA; Yuzo TERASHITA; Masayoshi AKIYAMA; Shohei KAJIKAWA
Journal of the Japan Society for Technology of Plasticity, The Japan Society for Technology and Plasticity, 63, 743, 174-179, Dec. 2022, Peer-reviwed
Scientific journal

Circular tube fabrication by extrusion of wood powder with natural binder using cooled die
Megumi Goto; Yuya Suzumoto; Shohei Kajikawa; Takashi Kuboki
Tubehydro 2022, 66-73, 16 Nov. 2022, Peer-reviwed
International conference proceedings, English

Cylindrical Tube Fabrication by Wood Forging
Hinako Uejima; Takashi Kuboki; Shohei Kajikawa
Tubehydro 2022, 74-81, 16 Nov. 2022, Peer-reviwed
International conference proceedings, English

Feasibility study on application of spinner straightening to thick-walled tube
Tetsuya Komatsu; Shohei Kajikawa; Shinsuke Inoue; Matsumura Hiromichi; Hikaru Seimiya; Takashi Kuboki
Corresponding, Tubehydro 2022, 270-277, 16 Nov. 2022, Peer-reviwed
International conference proceedings, English

Effects of Fin Shape and Tube Thickness on Forming Accuracy and Forming Limit in Rotational Drawing and Bending of Finned Copper Tubing
Riku Yanada; Shohei Kajikawa; Tsuneo Haba; Yasuhiro Ueno; Takashi Kuboki
Corresponding, Tubehydro 2022, 176-184, 15 Nov. 2022, Peer-reviwed
International conference proceedings, English

Development of Flexible Bending Process with Controllable Bending Radius and High Cross-sectional Circularity
Kazuhito Takahashi; Shohei Kajikawa; Riku Usui; Riku Yanada; Takashi Kuboki
Corresponding, Tubehydro 2022, 185-193, 15 Nov. 2022, Peer-reviwed
International conference proceedings, English

Effect of Strain Rate and Punch Shape on Formability in Flaring Process for Tube Diameter Expansion in the Finite Element Analysis
Tsuyoshi Muraoka; Yusuke Okude; Shohei Kajikawa; Takashi Kuboki
Corresponding, Tubehydro 2022, 201-210, 15 Nov. 2022, Peer-reviwed
International conference proceedings, English

Optimization of Contact Angle in Rotary Tube Flaring with Relieved Punch for Realizing High Forming Limit
Shohei Kajikawa; Kazumasa Iizuka; Takashi Kuboki
Tubehydro 2022, 211-216, 15 Nov. 2022, Peer-reviwed
International conference proceedings, English

The influence of mechanical properties of parent tube on formability in the expansion drawing process
Shiliang Zhang; Takashi Kubo; Masayoshi Akiyamaki; Shohei Kajikawa
Tubehydro 2022, 253-260, 15 Nov. 2022, Peer-reviwed
International conference proceedings, English

Circular Tube Forming by Using Extrusion of Wood Powder Combined with Sucrose and Citric Acid
Yuya Suzumoto; Shohei Kajikawa; Takashi Kuboki
Journal of the Society of Materials Science, Japan, 70, 12, 912-917, 01 Dec. 2021, Peer-reviwed
Scientific journal, Japanese

Effect of Contact Area on Formability in Rotary Flaring Using Conical Punch with Groove
Kazumasa Iizuka; Shohei Kajikawa; Takashi Kuboki
COMPLAS XVI, Paper No. 592 (Abstractのみ), 09 Sep. 2021
Scientific journal, English

Finite Element Analysis of Multi-stage Deep Drawing for Forming deep Rectangular Case with High Aspect Ratio
Shohei Kajikawa; Tomoya Takasan; Takashi Kuboki; Kenji Tamaoki; Katsuyuki Onishi; Akira Gunji; Akira Yamauchi
COMPLAS XVI, Paper No. 556 (Full paper), 09 Sep. 2021
International conference proceedings, English

Fabrication of a Ring Groove on Inner Surface of tube by Ironing from Outer Surface Using Displacement Control of Tube Bottom End
Junki Ishino; Shohei Kajikawa; Akira Yamauchi; Akira Gunji; Katsuyuki Onishi; Takashi Kuboki
Corresponding, COMPLAS XVI, Paper No. 552 (Full paper), 09 Sep. 2021
International conference proceedings, English

Development of Twisting Method of Sheet Metal Using Taper Roller
Avanish Kumar; Takahiro Makiyama; Shohei Kajikawa; Takashi Kuboki
Corresponding, COMPLAS XVI, Paper No. 541 (Full paper), 09 Sep. 2021
International conference proceedings, English

A New Ductile Fracture Criterion for Skew Rolling And Its Application to Evaluate the Effect of Number of Rolls
Koji Yamane; Kazuhiro Shimoda; Koichi Kuroda; Shohei Kajikawa; Takashi Kuboki
Corresponding, COMPLAS XVI, 291, 5, Paper No. 677 (Abstractのみ), 09 Sep. 2021
International conference proceedings, English

Asymmetric sheet-metal V-bending applying separate dies with different velocities for diversified bending shapes and operability
Takashi Kuboki; Takahiro Hadano; Wataru Oba; Shohei Kajikawa; Yingjun Jin
Lead, CIRP Annals, Elsevier Ltd., 70, 1, 219-222, 10 Aug. 2021, Peer-reviwed
Scientific journal, English

Fluidity of Wood Composite Combined with Natural Binder on Injection Molding
Shohei Kajikawa; Masaya Horikoshi; Takashi Kuboki; Soichi Tanaka; Kenji Umemura; Kozo Kanayama
Proc. 13th Int. Conf. Techn. Plast. (ICTP2021), Springer International Publishing, 2031-2040, 26 Jul. 2021, Peer-reviwed
Scientific journal, English

Effect of Bending Intensity on Straightness in Spinner Straightener
Keiichiro Kawasaki; Shohei Kajikawa; Hiromichi Matumura; Tetushi Ono; Hikaru Seimiya; Takashi Kuboki
Corresponding, Proc. 13th Int. Conf. Techn. Plast. (ICTP2021), 2055-2065, 26 Jul. 2021, Peer-reviwed
Scientific journal, English

Effect of Expansion Ratio on Formability in Tube Drawing with Diameter Expansion
Hikaru Kawaguchi; Takashi Kuboki; Isamu Akasaka; Yuzo Terashita; Masayoshi Akiyama; Shohei Kajikawa
Proc. 13th Int. Conf. Techn. Plast. (ICTP2021), 1043-1053, 26 Jul. 2021, Peer-reviwed
Scientific journal, English

Tube forming and fabricating technologies for contributing society by tackling problems of Environment and Aging Population [Title_in_jpn] none
Takashi Kuboki; Atsushi Shirayori; Masaaki Mizumura; Noah Utsumi; Yeong-Maw Hwang
Lead, Proc. 13th Int. Conf. Techn. Plast. (ICTP2021), Springer International Publishing, 2883-2897, 26 Jul. 2021, Peer-reviwed
International conference proceedings, English

Flange compression using stepped punch for forming extremely deep cup with flange from aluminum alloy sheet
Shohei Kajikawa; Takashi Kuboki; Takashi Iizuka
Journal of Materials Processing Technology, 2, 288, 01 Feb. 2021, Peer-reviwed, This paper presents a method of flange compression using a stepped punch and die for effective production of an extremely deep cup with a flange from sheet metal. The proposed method was composed of initial stretching and flange compression, and fracture was prevented during the flange compression as the blank elongates by only compressive force. Optimum forming parameters, which are stepped lengths of the punch and clearance between the punch and the die, were investigated by finite element analyses and experiments. It was possible to produce a deep cup with uniform side wall thickness, which length-to-diameter ratio was 2.00, by the optimization of the forming parameters. In addition, two-step forming, which uses two punches, was proposed for producing an extremely deep cup with a thinner side wall. As a result, the deep cup, which length-to-diameter ratio was 9.23, was obtained.
Scientific journal, English

傾斜圧延において介在物が内部割れに及ぼす影響
Koji YAMANE; Kazuhiro SHIMODA; Koichi KURODA; Shohei KAJIKAWA; Takashi KUBOKI
Corresponding, J. Jpn. Soc. Technol. Plast., 62, 720, 1-7, 25 Jan. 2021, Peer-reviwed
Scientific journal, Japanese

Tube Drawing Process with Diameter Expansion for Effectively Reducing Thickness
Shohei Kajikawa; Hikaru Kawaguchi; Takashi Kuboki; Isamu Akasaka; Yuzo Terashita; Masayoshi Akiyama
Metals, 12, 10, Article Number 1642, 06 Dec. 2020, Peer-reviwed
Scientific journal, English

Ball Spin Forming for Flexible and Partial Diameter Reduction in Tubes
Shota Hirama; Takayuki Ikeda; Shiori Gondo; Shohei Kajikawa; Takashi Kuboki
Corresponding, Metals, MDPI AG, 10, 12, Article number 1627-1627, 04 Dec. 2020, Peer-reviwed, This paper proposed a new ball spin forming equipment, which can form a reduced diameter section on the halfway point of a tube. The effects of forming process parameters on the surface integrity and deformation characteristics of the product were investigated. The proposed method can reduce the diameter in the middle portion of the tube, and the maximum diameter reduction ratio was over 10% in one pass. When the feed pitch of the ball die was more than 2.0 mm/rev, spiral marks remained on the surface of tube. Torsional deformation, axial elongation and an increase in thickness appeared in the tube during the forming process. All of them were affected by the feed pitch and feed direction of the ball die, while they were not affected by the rotation speed of the tube. By sending the ball die towards the fixed part of the tube or by increasing the feed pitch, torsional deformation and elongation decreased, and the amount of thickening increased. When the tube was pressed perpendicularly to the axis without axial feed, a diameter reduction ratio of 21.1% was achieved without defects using a ball diameter of 15.9 mm. The polygonization of the tube was suppressed by reducing the pushing pitch. The ball spin forming has a high advantage in flexible diameter reduction processing on the halfway point of the tube for producing different diameter tubes.
Scientific journal, English

Effect of Particle Size on Thermal Flow of Japanese Cedar Powder Combined with Sucrose and Citric Acid
Shohei Kajikawa; Kiu Cho; Takashi Kuboki; Soichi Tanaka; Kenji Umemura; Kozo Kanayama
Journal of the Society of Materials Science, Japan, 69, 6, 440-450, 01 Jun. 2020, Peer-reviwed
Scientific journal, Japanese

Fabrication of Naturally Derived Wood Products by Thermal Flow Molding of Wood Powder with Sucrose and Citric Acid,
Kajikawa Shohei; Horikoshi Masaya; Kuboki Takashi; Tanaka Soichi; Umemura Kenji; Kanayama Kozo
BioResources, 15, 1, 1702-1715, Jan. 2020, Peer-reviwed
Scientific journal, English

Flexible Diameter Reduction of Tubes with Planetary Balls
Takayuki Ikeda; Shohei Kajikawa; Takashi Kuboki
Corresponding, Tubehydro 2019, 138-144, 20 Nov. 2019, Peer-reviwed
International conference proceedings, English

Recent trends and perspectives in tube forming
Takashi Kuboki
Tubehydro 2019, 1-10, 19 Nov. 2019, Peer-reviwed, Invited
International conference proceedings, English

Improvement of dimensional precision in two-step shear bending method using mandrels
Takashi Kuboki; Daisuke Kusuda; Shohei Kajikawa; Takahiro Noguchi; Kazuaki Adachi
Lead, Tubehydro 2019, 59-66, 19 Nov. 2019, Peer-reviwed
International conference proceedings, English

Experimental investigation of new tube drawing process with diameter expansion
Shohei Kajikawa; Hikaru Kawaguchi; Takashi Kuboki; Isamu Akasaka; Yuzo Terashita; Masayoshi Akiyama
Tubehydro 2019, 67-74, 19 Nov. 2019, Peer-reviwed
International conference proceedings, English

Analysis of spinner straightening utilizing the finite element method
Takashi Kuboki; Keiichiro Kawasaki; Shohei Kajikawa; Hiromichi Matsumura; Tetsushi Ono; Hikaru Seimiya
Lead, XV International Conference on Computational Plasticity (COMPLAS XV), 21-30, 03 Sep. 2019
International conference proceedings, English

Finite element analysis of tube drawing process with diameter expansion
Shohei Kajikawa; Hikaru Kawaguchi; Takashi Kuboki; Isamu Akasaka; Yuzo Terashita; Masayoshi Akiyama
XV International Conference on Computational Plasticity (COMPLAS XV), 48-58, 03 Sep. 2019
International conference proceedings, English

Two-step shear bending of tube with small bending radius for satisfying both space conservation and inner gas/liquid fluidity
TakashiKuboki; DaisukeKusuda; ShoheiKajikawa; Takahiro Noguchi; Kazuaki Adachi
Lead, CIRP Annals, 68, 1, 301-304, Aug. 2019, Peer-reviwed
Scientific journal, English

Two-step forming for improvement of forming limit in rotary nosing with relieved die for fabrication of axisymmetric and eccentric nosed tubes
Wataru Oba; Yusuke Imaizumi; Shohei Kajikawa; Takashi Kuboki
Journal of Materials Processing Technology, 262, 350-358, 01 Dec. 2018, Peer-reviwed
Scientific journal, English

Prevention of defect by optimizing mandrel position and shape in rotary draw bending of copper tube with thin wall
Shohei Kajikawa; Guanghui Wang; Takashi Kuboki; Masato Watanabe; Akinori Tsuchiya
Procedia Manufacturing, 15, 828-835, 31 Aug. 2018, Peer-reviwed
Scientific journal, English

Fabrication of ring groove on inner surface of cylindrical blank by ironing from outer surface
Tatsunori Ozawa; Takashi Kuboki; Shohei Kajikawa; Akira Yamauchi; Akira Gunji; Katsuyuki Onishi
Corresponding, Procedia Manufacturing, 15, 899-906, 31 Aug. 2018, Peer-reviwed
Scientific journal, English

An extrusion method of tube with spiral inner fins by utilizing generation of spiral outer fins/grooves
Takashi Kuboki; Michiaki Ishikawa; Shohei Kajikawa; Makoto Murata
Lead, CIRP Annals, Elsevier USA, 67/1, 305-308, Aug. 2018, Peer-reviwed, This paper presents a new extrusion method for fabrication of a tube with spiral inner fins. The spiral fins are formed by utilizing the generation of spiral outer fins or grooves, which drive the metal to circumferentially move with twist deformation. The effect of the outer fins/grooves is examined for realizing the circumferential metal flow. The position of the mandrel has an ability to flexibly control the spiral angle. This method would drastically enhance the productivity and reduce the manufacturing cost, as the tube would be manufactured directly from a billet through only one process.
Scientific journal, English

Flexibility in metal forming
D. Y. Yang; M. Bambach; J. Cao; J. R. Duflou; P. Groche; T. Kuboki; A. Sterzing; A. E. Tekkaya; C. W. Lee
CIRP Annals, Elsevier USA, 64, 2, 743-765, Aug. 2018, Peer-reviwed, Flexibility in metal forming is needed more than ever before due to rapidly changing customer demands. It paves the way for a better control of uncertainties in development and application of metal forming processes. Although flexibility has been pursued from various viewpoints in terms of machines, material, process, working environment and properties, etc., a thorough study of the concept was undertaken in order to with problems of manufacturing competiveness and tackle new challenges of manufacturing surroundings. Therefore, in this paper, flexibility in forming is reviewed from the viewpoints of process, material, manufacturing environment, new process combinations and machine–system–software interactions.
Scientific journal, English

EXAMINATION OF WORKING CONDITION FOR REDUCING THICKNESS VARIATION IN TUBE DRAWING WITH PLUG
Takashi Kuboki; Shunsuke Tasaka; Shohei Kajikawa
Lead, COMPUTATIONAL PLASTICITY XIV: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 63-71, Sep. 2017, The present research carried out a series of analyses using the finite element method (FEM). The analyses investigated the effect of working condition on thickness variation after drawing a tube with initial thickness distribution. As a result, it was notably revealed that application of dies with small half angle below 5 degrees was prominently effective for levelling the thickness variation. This effect was strengthen by employing tubes with thicker walls and larger diameters. Moreover, the mechanism of levelling the thickness variation was also examined. The small die angle affects the contact length at die approach, and the contact length at thinnest side becomes longer than that at the thickest side. The difference of the contact lengths equalizes the thicknesses of the thinnest and thickest sides. The analyses also predicted the thickness variation should almost be zero under an optimum condition.
International conference proceedings, English

EFFECT OF TOOL DESIGN ON FORMABILITY IN DEEP DRAWING BY APPLYING COMPRESSIVE FORCE ON FLANGE
Shohei Kajikawa; Takashi Kuboki; Takashi Iizuka
COMPUTATIONAL PLASTICITY XIV: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 54-62, Sep. 2017, This paper presents a new deep drawing process which applies compressive force on a flange for forming a deep cup effectively. This method uses a punch with a convex and a die, and optimum tool design was investigated using the finite element method (FEM) in order to prevent the formation of defects. First, the effect of the punch configuration was investigated. As a result, a cup with a uniform side wall thickness was obtained under the condition that the punch convex length was greater than the blank thickness and the punch top corner radius was appropriate. It was possible to obtain the deep cups by decreasing the clearance between the punch convex and the die. However, dimensional accuracy decreased with the decrease in the clearance. Based on these results, two-steps process using a backward punch was proposed, and deep cups having high dimensional accuracy was formed successfully by this method.
International conference proceedings, English

Proposal of a numerical model using the finite element analysis of pilger rolling for improvement of computation precision and efficiency
Tsuyoshi Muraoka; Takashi Kuboki; Shohei Kajikawa; Daisaku Yanaga; Kouichi Kuroda
Corresponding, Procedia Engineering, Elsevier Ltd, 207, 2364-2369, Sep. 2017, Peer-reviwed, This paper presents a new numerical analysis method for cold pilger rolling which leads to compatible improvement of analysis accuracy and shortening calculation time. In pilger rolling, a raw tube is rolled by dozens of "shots", which is repetitive reciprocating movement of caliber rolls. Previous studies carried out only one shot analysis for shortening calculation time. However, these studies cannot consider an accumulated plastic strain by the dozens of "shots". The proposed method is composed of two models. In the first preliminary model, the accumulated plastic strain is evaluated based on the strain increment between the two continuous shots. The second main model is given the pre-strain calculated by the preliminary model, and analyses of shots are conducted until tool load becomes stable. This paper clarified the number of shots until stable tool load was obtained in the proposed model. In addition, the proposed model can improve analysis accuracy of the rolling load while shortening calculation time by 60 %, compared with the conventional models of dozen of shots.
International conference proceedings, English

Two-step forming for improvement of forming limit in rotary nosing with relieved die for reduction of tube tip
Wataru Oba; Yusuke Imaizumi; Shohei Kajikawa; Takashi Kuboki
Corresponding, Procedia Engineering, Elsevier Ltd, 207, 1743-1748, Sep. 2017, Peer-reviwed, This paper presents an application of two-step forming for improvement of the forming limit in rotary nosing with relieved die. Nosing is one of the methods used for reduction of the diameter of a tube tip. "Two-step nosing", in which the working process of nosing is divided into two stages, applies two dies with different shapes at the former and latter stages. The die shapes are determined based on the occurrence tendency of defects in "
one-step nosing"
which uses only one die through the whole process. In this research, a series of experiments and numerical analyses of one-step nosing were carried out to investigate the mechanism of occurrence of each defect. As a result, it is revealed that the occurrence of defects was highly relevant to the contact area between the die and tube. Two-step nosing was thereafter carried out and attained the improvement of the forming limit, which was 9 % higher than one-step nosing under the optimum condition. Furthermore, additional experiments of forming eccentric tubes were conducted for fabrication of products with complex shapes.
International conference proceedings, English

Upset of bent wire/tube for fabrication of in-plane bent sheet metals with extremely large breadth and small bending radius
Takashi Kuboki; Tsuyoshi Muraoka; Tsubasa Tsubouchi; Shohei Kajikawa
Lead, CIRP ANNALS, ELSEVIER SCIENCE BV, 66, 1, 277-280, Aug. 2017, Peer-reviwed, This paper presents a new method for fabrication of a ring/coil of in-plane bent sheet metal using a wire/tube as a raw material. The method conducts upset of a wire/tube bent by a coiling process. The coiling process bends a circular wire/tube into a ring/coil, and the upset process compresses it into a ring/coil with extremely flattened cross-section and small bending radius, which was difficult to obtain by conventional processes. The breadth-to-thickness ratio reached 6.0 and the outer radius-to-breadth ratio decreased to 1.7. When the method is applied for coils, the fabricated coils would be used as joints in a surgical manipulator. (C) 2017 Published by Elsevier Ltd on behalf of CIRP.
Scientific journal, English

Forming method and characteristics of coiled spring in small coil diameter and with high rectangular ratio in winding wire cross section
T. Muraoka; T. Tsubouchi; K. Takahashi; T. Kuboki; S. Kajikawa
Corresponding, INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, SPRINGER LONDON LTD, 91, 5-8, 2635-2643, Jul. 2017, Peer-reviwed, This paper presents a new forming method of a coiled spring which is used as a forceps manipulator of a surgical robot. Joint parts of forceps manipulator are required to be "easy to bend and strong to twist". This demand is fulfilled by using coiled springs with high rectangular ratio in winding wire cross section. However, the coiled springs are conventionally expensive as they are fabricated by machining. This study proposed a new and inexpensive forming method for fabrication of the coiled spring with high rectangular ratio in the wire cross section. In this method, the coiled spring with circular shape in the winding wire cross section is compressed in the coil axial direction by upsetting, and then the rectangle ratio of the wire becomes high. The coiled spring with a high rectangular ratio of 3 was obtained by the proposed method. In addition, a numerical analysis and an experiment were conducted for evaluation of the formed coiled springs in terms of tensile, torsional, and bending characteristics. The formed coiled springs were easy to bend and strong to twist from results. Moreover, the elastic limit of the formed coiled springs improved due to work hardening by upsetting.
Scientific journal, English

Effect of groove shape and dimension of die on formability in tube extrusion with spiral inner projections
Michiaki Ishikawa; Taro Yagita; Takashi Kuboki; Shohei Kajikawa; Makoto Murata
Corresponding, The 9th Pacific Rim International Conference on Advanced Materials and Processing (PRICM9), 38-41, 02 Aug. 2016, Peer-reviwed
International conference proceedings, English

A rotary reduction of fine wires/tubes of a wide range of diameters using a pair of concave rolls
Takashi Kuboki; Shohei Kajikawa
Lead, CIRP ANNALS, ELSEVIER SCIENCE BV, 65, 1, 277-280, Aug. 2016, Peer-reviwed, This paper presents an innovative rotary reduction method of elongated fine solid wires and hollow tubes, the diameters of which could be reduced to 0.02 times of diameter of rolls as the tool. A pair of concave rolls is positioned at a skew angle to the material axis, and the rolls compress the material. The material travels between the rolls in a spiral movement with tension applied on its ends. The method is applicable for a very wide range of diameters using the same tools. Diversified shapes would be fabricated as the method reduces the diameter at arbitrary axial positions. (C) 2016 CIRP.
Scientific journal, English

Closed-loop control of product properties in metal forming
J. M. Allwood; S. R. Duncan; J. Cao; P. Groche; G. Hirt; B. Kinsey; T. Kuboki; M. Liewald; A. Sterzing; A. E. Tekkaya
CIRP ANNALS, ELSEVIER SCIENCE BV, 65, 2, 573-596, 2016, Peer-reviwed, Metal forming processes operate in conditions of uncertainty due to parameter variation and imperfect understanding. This uncertainty leads to a degradation of product properties from customer specifications, which can be reduced by the use of closed-loop control. A framework of analysis is presented for understanding closed-loop control in metal forming, allowing an assessment of current and future developments in actuators, sensors and models. This leads to a survey of current and emerging applications across a broad spectrum of metal forming processes, and a discussion of likely developments. (C) 2016 The Author(s).
Scientific journal, English

Fabrication of deep cup with flange by in-plane stretch forming applying compressive force in thickness direction
Shohei Kajikawa; Takashi Iizuka; Takashi Kuboki
Key Engineering Materials, Trans Tech Publications Ltd, 716, 897-906, 2016, Peer-reviwed, This paper presents a new stretch forming method that applies compressive force for forming a deep cup with a flange. In this method, a punch and a die having a hole are used, and the main parameters are the depth of the die hole and the clearance between the punch and the die. The effect of the depth of the die hole and the clearance between the punch and the die was investigated by using an aluminum blank of thickness 2 mm in an experiment and a finite element analysis (FEA). When the die hole depth was too small, the material flow could not be controlled appropriately, and when the die hole depth was too large, a local thinning occurred during initial stretching into the die hole. When the clearance was set at large, the side wall thickness of the formed cup was uneven, but a deep cup could be obtained by setting the clearance below a half of the blank thickness. As a result, a deep cup of height 8.3 mm and with a flange was formed successfully under the condition that the die hole depth was 1.5 mm and the clearance was 0.5 mm.
International conference proceedings, English

Stability of a suppression method of dent and spring-back in zigzag bending of sheet metal/plate
Takashi Kuboki; Takuma Yamada; Shohei Kajikawa; Hiroyuki Abe
Lead, Key Engineering Materials, Trans Tech Publications Ltd, 716, 931-940, 2016, Peer-reviwed, This paper focuses upon zigzag-shape bending for suppression of defects, including dent and springback. A series of finite element analyses was carried out in order to optimize the bending condition for suppression of these defects. As a result, it was clarified that a diagonal movement of the upper die was effective for suppression of dents while a rather vertical movement of the upper die was effective for suppression of springback. In order to suppress dent and springback at the same time, this paper proposes another method of bending method, whereby the upper die with special shape moves in a diagonal way. Moreover, the stability of the method against variation of tool dead position, which would be caused by elastic deformation of supporting members, was studied by FEM, followed by experimental verification.
International conference proceedings, English

Light press of sheet metal edge for reducing residual stress generated by laser cutting considering mechanical properties and intensity of residual stress
Atsushi Maeda; Yingjun Jin; Takashi Kuboki
Corresponding, JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 225, 178-184, Nov. 2015, Peer-reviwed, Laser cutting has started to be used as an effective method for cutting out blanks from rolled sheet metals because of its high flexibility for cutting lines and high productivity. However, residual stresses, which are generated by laser cutting, have been the greatest obstacle for the popularization of laser cutting. One of the problems is the warp which appears in the sheet metal after being subjected to bending processes after laser cutting. The authors present a light press method for reducing residual stress generated by laser cutting. The method is to give a light press on the sheet metal edge and to reduce tensile residual stress generated near the laser cutting surface. In particular, this present paper especially focuses upon optimization of working conditions depending on mechanical properties of the blank and the effect of the heat affected zone in laser cutting. Experiments of U-bending after applying light press were conducted for usability of this method. The FEM analyses were carried out in order to investigate proper working conditions depending on various mechanical properties. As a result, the optimum press pressure of the light press method for various mechanical properties was found out for reducing residual stress which caused by laser cutting, by taking warp after U-bending as an evaluation parameter. The relationship between the optimum pressure and the proof stress was quantitatively and specifically clarified for several sets of mechanical properties. It was also found that the influence of heat-affected-zone area and intensity of residual stress by laser cutting on the optimum press pressure was small. (C) 2015 The Authors. Published by Elsevier B.V.
Scientific journal, English

Effect of mandrel position in draw bending of copper tube with thin wall and small diameter
Guanghui Wang; Takashi Kuboki; Masato Watanabe; Akinori Tsuchiya
Corresponding, Tubehydro 2015, 273-280, 10 Sep. 2015, Peer-reviwed
Scientific journal, English

A METHOD FOR SUPPRESSION OF DEFECTS IN ZIGZAG BENDING OF SHEET METAL
Takashi Kuboki; Shota Tanabe; Takahiro Mochizuki; Hiroyuki Abe
Lead, COMPUTATIONAL PLASTICITY XIII: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 46-54, Sep. 2015, This study presents methods for suppression of defects observed in zigzag bending of sheet-metal or plate. This type of bending is widely used in industry for manufacturing structural parts in automobiles. Although it is easily conducted by press forming using upper and lower dies which have zigzag shape, it often has defects, such as spring-back and dents. A series of finite element analyses and experiments were conducted for suppression of the defects in two-place bending, which has three segments. As a result, it is revealed that that the distance between two bending positions is dominant for occurrence of the dents and that the dent area was able to be reduced by selecting the optimum moving direction of the upper die. It is also revealed that the cause of spring-back is elastic recovery of the straight segments instead of the bent parts against engineers' and technicians'' intuition, and that there is an optimum moving direction of the upper die for the least spring-back. Furthermore, another realistic method for suppression of spring-back was suggested for four-place bending.
International conference proceedings, English

Flexible rotary reduction of tube tips by dies with relief surfaces for attaining high forming limit and productivity
Takashi Kuboki; Mitsumasa Abe; Yohei Yamada; Makoto Murata
Lead, CIRP Annals, Elsevier BV, 64, 1, 269-272, Aug. 2015
Scientific journal

Die design for deep drawing with high-pressured water jet utilizing computer fluid dynamics based on Reynolds' equation
Y. Horikoshi; T. Kuboki; M. Murata; K. Matsui; M. Tsubokura
Corresponding, JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 218, 218, 99-106, Apr. 2015, Peer-reviwed, This paper proposes a new die design for deep drawing with high-pressured water jet. The authors had previously proposed a deep drawing method with high-pressured water jet. The water jet enables deep drawing without oil or other chemical lubricants, which might require some additional processes for lubricant removal and become a nuisance in the environment. One of the problems in the method using a prototype die with 8 nozzles in the hoop direction had been that the pump pressure had to be boosted significantly high for successful deep drawing, leading to scars on the surface of the deep drawn product. In the present paper, two new concepts of design were introduced with the help of computational fluid dynamics (CFD) for water film considering the blank deformation obtained by the finite element method (FEM). The first concept is that the number of nozzles should be increased from 8 to 16, and that the position of the added 8 nozzles should be positioned on the flange part of the die as a result of the CFD. The second concept is to shallowly engrave a looped ditch linking the nozzles. The CFD showed that while the die without the looped ditch generated an area of reduced pressure between the nozzles, the ditch-engraved die maintained the pressure, resulting in satisfactorily strong uplift force on the blank even at relatively low pump pressure. A series of experiments also verified the numerical results, and proved the excellence of the ditch-engraved die. (C) 2014 Elsevier B.V. All rights reserved.
Scientific journal, English

CNC tube forming method for manufacturing flexibly and 3-dimensionally bent tubes
Makoto Murata; Takashi Kuboki
60 Excellent Inventions in Metal Forming, Springer Berlin Heidelberg, 363-368, 01 Jan. 2015, Peer-reviwed, This article presents an innovative computer numerical control (CNC) tube forming method, called MOS bending, which manufactures flexibly and 3-dimensionally bent tubes and was put into practical use in industry. The machine for MOS bending is mainly composed of a bending die and a guide cylinder. Numerically controlled positioning of the bending die in vertical and horizontal directions realizes flexible bending in arbitrary bending radius and arbitrary direction. The variety of the bent shapes includes conventional 2-dimensional arcs, convoluted patterns in a plane, extremely large bending radii, 3-dimensional solenoids and other 3-dimensional complex shapes. The flexibly bent tubes are suitable for ornamental usages as interior and exterior decorations as well as automotive components. MOS bending revolutionarily changes the image of tube bending. The above and other benefits of MOS bending are reviewed here, together with its mechanism and some examples of products.
In book, English

EFFECT OF INITIAL THICKNESS DEVIATION AND REDUCTION ON LONGITUDINAL AND CROSS-SECTIONAL PRECISION AFTER TUBE DRAWING USING PLUG
Shunsuke Tasaka; Takashi Kuboki; Kouichi Kuroda; Tatsuya Okui
COMPUTATIONAL PLASTICITY XIII: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 55-64, 2015, Peer-reviwed, In this research, 2D and 3D FEM models are composed for the clarification of the effect of initial thickness distribution on its distribution after drawing and the residual stresses. In the 2D FEM, the minimum bare element number was determined in terms on both residual stress precision and calculation time. Based on the results of 2D FEM, the element number in 3D FEM was determined. Using the obtained 3D FEM, the effect of initial thickness distribution was clarified with the combination of thickness reduction. It was revealed that light reduction in thickness in plug drawing sometimes lead to increase of thickness deviation, against intuitive prediction based on tube drawing without plug. On the other hand, increase of thickness reduction resulted in decrease of thickness deviation. The mechanism of thickness change was also examined.
International conference proceedings, English

Method of reducing residual stress generated by laser cutting by light indentation
Yingjun Jin; Takahiro Shibata; Atsushi Maeda; Takashi Kuboki
Corresponding, 塑性と加工, The Japan Society for Technology of Plasticity, 55, 646, 1003-1007, 25 Nov. 2014, Peer-reviwed, The aim of the present research is to propose a new method for the reduction of the residual stress which was generated by laser cutting. Laser cutting has been expected to be used as an effective and potent method for cutting out blanks from rolled sheet metals because of its high flexibility of the cutting line and high productivity. However, residual stresses, which are inevitably generated by laser cutting, have been the greatest obstacle to the prevalence of laser cutting. One of the problems is the warping that occurs in the sheet metal subjected to bending processes following laser cutting. The authors present a new method for reducing residual stress generated by laser cutting. The method involves applying is to give light indentation on the sheet metal edge. The FEM analyses were carried out to study the feasibility of this method, to determine the method of applying indentation, and to optimize the conditions. Experiments were conducted for verification. As a result, the warp generated by the residual stress was significantly reduced to one-tenth of that without the new treatment, and the magnitude was satisfactorily small for industrial usage.
Scientific journal, Japanese

Method of reducing residual stress generated by laser cutting by light indentation of sheet metal edge
Atsushi Maeda; Yingjun Jin; Takashi Kuboki
Corresponding, 11TH INTERNATIONAL CONFERENCE ON TECHNOLOGY OF PLASTICITY, ICTP 2014, ELSEVIER SCIENCE BV, 81, 413-418, Oct. 2014, Peer-reviwed, Laser cutting has started to be used as an effective method for cutting out blanks from rolled sheet metals because of its high flexibility for cutting line and high productivity. However, residual stresses, which are generated by laser cutting, have been the greatest obstacle for the popularization of laser cutting. One of the problems is the warp which appears in the sheet metal, after being subjected to bending processes after laser cutting. The authors present a light indentation method for reducing residual stress generated by laser cutting. The method is to give light indentation on the sheet metal edge and to reduce tensile residual stress generated near the laser cutting surface. In particular, this present paper especially focuses upon optimization of working condition depending on mechanical properties of blank. Furthermore, the mechanism of transition of stress and effective strain in light indentation was examined. Experiments of U-bending after applying light indentation were conducted for usability of this method. The FEM analyses were carried out in order to investigate the effect of working condition in various mechanical properties. As a result, the optimum condition of light indentation method in various materials was found out, and the warp of bent sheet metals was drastically reduced. (C) 2014 The Authors. Publsihed by Elsevier Ltd.
International conference proceedings, English

Deep drawing with high-pressured water jet using ditch-engraved die
Yuki Horikoshi; Takashi Kuboki; Makoto Murata; Kazumi Matsui; Makoto Tsubokura
Corresponding, 11TH INTERNATIONAL CONFERENCE ON TECHNOLOGY OF PLASTICITY, ICTP 2014, ELSEVIER SCIENCE BV, 81, 893-898, Oct. 2014, Peer-reviwed, This paper proposes a new die design for deep drawing with high pressured water jet. The authors had previously proposed a deep drawing method with high-pressured water jet. The water jet enables deep drawing without oil or other chemical lubricants, which might require some additional processes for lubricant removal and become nuisance in environment. One of the problems in the method using a prototype die with 8 nozzles in hoop direction had been that the pump pressure had to be boosted significantly high for successful deep drawing, leading to scars on the surface of deep drawn product. In the present paper, two new concept of design was introduced with the help of computational fluid dynamics (CFD) for water film considering the blank deformation obtained by the finite element method (FEM). The first concept is that the number of nozzles should be increased from 8 to 16, and that the position of the added 8 nozzles should be positioned on the flange part of the die as a result of the CFD. The second concept is to shallowly engrave a looped ditch linking the nozzles. The CFD showed that while the die without the looped ditch generated area of reduced pressure between the nozzles, the ditch-engraved die maintained the pressure, resulting in satisfactorily strong uplift force on the blank even at relatively low pump pressure. A series of experiments also verified the numerical results, and proved the excellence of the ditch-engraved die. (C) 2014 Published by Elsevier Ltd.
International conference proceedings, English

Development of coiled springs with high rectangular ratio in cross-section
Tsubasa Tsubouchi; Kazuhito Takahashi; Takashi Kuboki
Corresponding, 11TH INTERNATIONAL CONFERENCE ON TECHNOLOGY OF PLASTICITY, ICTP 2014, ELSEVIER SCIENCE BV, 81, 574-579, Oct. 2014, Peer-reviwed, Some robots often have to be made compact as they work in limited spaces, for example, in disaster rescue sites and operation theatres for surgery. One of the problems in downsizing the robots is how to fabricate the joints which are complicated and tend to be large. Coiled springs with high rectangular ratio recently have started to be used as the joint mechanism, because they are compact, easy to be bent, and able to convey strong twist force. However, these springs are now made by machining, resulting in low productivity and high cost. In this study, a new and inexpensive forming method is proposed, where a stainless wire is wound around into the shape of coiled spring, and subjected to upset in the spring axis direction. The finite element analysis was conducted for estimation of the work-hardening. The high work-hardening will realize the high yield stress, which is one of important features required for robot joints, as they must be used without plastic deformation. Based on the analysis, a series of experiments were carried out, and the formed springs were evaluated in terms of tension, torsion and bending characteristics. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
International conference proceedings, English

Formability improvement by die-bearing grooves in tube extrusion with spiral inner projections
Taro Yagita; Takashi Kuboki; Makoto Murata
11TH INTERNATIONAL CONFERENCE ON TECHNOLOGY OF PLASTICITY, ICTP 2014, ELSEVIER SCIENCE BV, 81, 641-646, Oct. 2014, Peer-reviwed, Extruded tubes are used in many industrial fields. Many of these tubes have a same cross-sectional shape in axial direction. However, non-uniformity has recently begun to be required for these components in particular usage. For example, circular cupper tubes with spiral inner projections are used for the improvement of heat exchange in air conditioners. Roll forming is a suitable method for the manufacturing of cupper tubes. However, roll forming is applicable only for cupper and its productivity is not high, resulting in high cost. In the present paper, additional small grooves were newly carved on the surface of bearing for the acceleration of spiral movement of the tube during extrusion. While relatively small projections were formed on the outer surface by the die-bearing grooves, large ones were formed on the inner surface by the mandrel grooves. With increase of bearing length, the more the spirality was improved. Sufficient and stable spiral angles were achieved under appropriate conditions, compared to those extruded without die-bearing grooves. (C) 2014 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
International conference proceedings, English

A new incremental in-plane bending of thin sheet metals for micro machine components by using a tiltable punch
Takashi Kuboki; Armad Azrie; Yingjun Jin
Lead, CIRP Annals, Elsevier BV, 63, 1, 249-252, Aug. 2014, Peer-reviwed
Scientific journal, English

押出し加工による内面壁にねじられた突起を付けた円管の突起数の影響
村田 眞; 久保木 孝
塑性と加工, 日本塑性加工学会, 55, 637, 127-131, 25 Feb. 2014, Peer-reviwed, Extrusion components are used in many industrial systems, such as railroad vehicles and heat exchangers. The demand for components whose section and tube are not uniform is increasing, and there are several studies of nonuniform tubes. A typical extrusion study involves a tube with spiral projections on the inside wall. When the tubes are exchangers, such as in room air conditioners, they raise the heat exchange performance. If the exchanger tube are made of extruded aluminum, spiral projections formed on the inside wall can extend the limit of the exchanger. The exchanger tubes will become inexpensive and the productivity will be improved. We propose a new extrusion method for tubes with spiral projections on the inside wall in this study. The new extrusion method is suitable for mass production, and the setup spiral angle of projections is 30 degrees. The material flow of a billet is changed by the mandrel slots and the tubes with spiral projections on the inside wall are made. The extrusion conditions were experimentally discussed regarding the shape of circular tubes with spiral projections. We experimentally clarified the limit and characteristics of the extrusion of circular tubes with spiral projections on the inside wall in this study.
Scientific journal, Japanese

Characteristics of micro incremental in-plane bending of sheet metal using tiltable punch
Ahmad Azrie; Takashi Kuboki
Corresponding, COMPLAS XII, INT CENTER NUMERICAL METHODS ENGINEERING, 63-74, Sep. 2013, Incremental forming methods have gained interest in recent years as a forming technique for micro and fine components. This paper presents a newly developed incremental in-plane bending with tillable punch for micro-metal sheets whose thickness is less than 1mm. The punch has two unique points. Firstly, it has a joint which enables the punch tilt freely according to the contact pressure. Secondly, the punch "sole" has a trapezoidal shape, where the toe is thin and the heel is wide. With increase of indentation, the toe bites deeper into metal than the heel resulting in the thickness distribution. As a result, the thin sheet metal is bent without any difficulty of punch positioning. Among the conditions of incremental bending, the effects of the toe angle of the punch sole during contact on the bending radius are examined by experiments, calculations and analysis. As a result, incremental forming with a tool with a toe angle of 30 degrees results in the largest sheet-metal curvature.
International conference proceedings, English

A new schedule-free mandrel-less bending method for straight/pre-shaped long tubes
Takashi Kuboki; Kazuhito Takahashi; Kazuhiko Ono; Kozo Yano
Lead, CIRP ANNALS, ELSEVIER SCIENCE BV, 62, 1, 303-306, Aug. 2013, Peer-reviwed, The objective is to propose a new schedule-free mandrel-less draw-bending method to achieve high cross-sectional precision for straight and pre-shaped long tube, for which conventional methods lacking innovation are useless. The proposed method applies side compression on the tube. Analyses and experiments verified excellence of the method and the new method successfully reduced the error index of circularity under the severe conditions of conventional methods. The method would bring significant flexibility in manufacturing as the method is able to bend arbitrary portions of tubes and be placed in arbitrary positions of the process line. (C) 2013 CIRP.
Scientific journal, English

Extrusion of 1050 aluminum circular tube with many spiral projections on inside wall
Makoto Murata; Takashi Kuboki; Hiroyuki Yamazaki
Keikinzoku/Journal of Japan Institute of Light Metals, 63, 4, 135-140, 2013, Peer-reviwed, The extrusion components are used in many industrial fields, such as railroad vehicles, cars, heat exchangers and domestic articles. However, the demand of the component whose tube is not uniform on cross section is increasing. Circular tube of copper with spiral projections on the inside wall is used for the improvement of the heat exchange efficiency of the heat exchanger. The projections are conventionally manufactured by swaging. Some researchers tried to study the spiral projection on the tube, but nobody could make the tube. We modified the traditional extru-sion machine and can successfully extruded the trial circular tube with many spiral projections. The extrusion was performed by the mandrel with set up many grooves. When the plastic flow of the billet was changed to angle of spiral direction by grooves of mandrel, the tube with the spiral projections was produced. Therefore the important extrusion condition is mandrel height which is the mandrel position in the examination. When the mandrel hangs out die, circular tube is trusted by the slot mandrel. As the mandrel height gets higher, the tube will be strongly trusted. The billet material is 1050 aluminum. We examine the extruded circular tube experimentally with the many spiral projections by using the mandrel with many spiral slots. Furthermore, we will have to make the characteristic and limit of the tube with the many spiral projections clear. © 2013 The Japan Institute of Light Metals.
Scientific journal, Japanese

THE EFFECT OF DIE HALF ANGLE IN TUBE NOSING WITH RELIEVED DIE
Mitsumasa Abe; Takashi Kuboki
Lead, COMPUTATIONAL PLASTICITY XII: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 75-85, 2013, This research concentrates on rotary nosing using cone shape dies, in particular using "relieved dies". "Relieved die" is a cone-shape die with contact surfaces and ground-down relieved surfaces. The objective of this research is to improve the forming limit by reducing the necessary force during the process. The present research focuses attention on the effect of die half angle. Die half angle is important parameter because the angle of nosing depends on the angle of the die in press and rotary nosing. According to the previous research, the forming limit is highest when the number of contact areas is three [1]. Therefore, this paper researched on the effect of die half angle by experiment and calculation, FEM, under the condition that the number of contact areas is three. It is revealed that the optimum contact angle changes depending on the die half angle.
International conference proceedings, English

EVALUATION OF WATER FILM BY REYNOLDS EQUATION IN DEEP DRAWING USING HIGH-PRESSURED WATER JET
Takashi Kuboki; Yuki Horikoshi; Makoto Murata; Kazumi Matsui; Makoto Tsubokura
Lead, COMPUTATIONAL PLASTICITY XII: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 86-95, 2013, The authors had proposed a deep drawing method using high-pressured jet waters as lubricant. This method aimed to suppress the usage of oil or other chemical lubricants, which might require some additional processes for lubricant removal and become a nuisance in environment. The conditions had been determined through trial and error approach without knowing water behaviors as lubricant. As a result, some scars and dimples were observed on the surface of deformed cup. In the present paper, a numerical model was composed for the evaluation of the water behaviors as lubricant. Darcy-Weisbach equation was used for evaluation of pressure drop between nozzle exit and pump, while Reynolds' equation was used for the thin film of fluid between the die and blank. The data of blank deformation in FEM was considered for the determination of the thickness distribution of the fluid film. The characteristics of the water were evaluated by the composed numerical method, and the results were used for examination of lubrication characteristics in experiments.
International conference proceedings, English

内面に多数のねじられた突起を持つ円管の押出し加工
村田眞; 久保木孝; 小林雅志; 山崎弘之(LIXIL
日本塑性加工学会 学会誌「塑性と加工」, 53, 622, 48-52, Nov. 2012, Peer-reviwed
Scientific journal, Japanese

凹型ロールを用いたフリーサイズ伸線加工
久保木 孝; 仙崎 泰慎
Lead, 塑性と加工, 53, 622, 1008-1012, Nov. 2012, Peer-reviwed
Scientific journal, Japanese

内面に多数のねじられた突起を持つ円管の押出し加工
村田 眞; 久保木 孝; 小林 雅志; 山崎 弘之
塑性と加工, The Japan Society for Technology of Plasticity, 53, 622, 998-1002, Nov. 2012, Peer-reviwed, Circular tube of copper with spiral projections on the inside wall is used for the improvement of the heat exchange efficiency of the heat exchanger. The copper tube is made by swaging. The copper price is expensive and the swaging manufacture speed is late. If the tube is conventionally manufactured by extrusion and made of aluminum, not only the price of tube becomes cheap but also manufacture speed gets faster. And the projection of spiral shape for heat effective exchanger can be made. We modified the traditional extrusion machine and successfully extruded the trial extruded circular tube with many spiral projections on the inside wall. The billet material is lead. We discussed experimentally the influence of shape and the size on the trial extruded circular tube about processing conditions. The established number of projection is 20 and lead angle is 30 degree with the spiral projection on the inside wall of the circular tube. It was possible to extrude established circular tubes with many spiral projections on the inside wall under appropriated processing conditions.
Scientific journal, Japanese

Application of Rotary Nosing with Relieved Die to Thin Tube with Thickness Ratio of 0.83 %
Takashi Kuboki; Atsushi Kominami
Lead, Metal forming, 547-550, Sep. 2012, Peer-reviwed
International conference proceedings, English

Effect of Rolling Reduction on Mechanical Properties of Copper Plate
Takashi Kuboki; Toru Matsumoto; Yingjun Jin; Kenjiro Terada
Lead, Metal forming, 99-102, Sep. 2012
International conference proceedings, English

Influence of Billet Material of Extruded Circular Tube with Spiral Projections on Inside Wall
Makoto Murata; Takashi Kuboki; Masashi Kobayashi; Hiroyuki Yamazaki
Metal forming, 463-466, Sep. 2012, Peer-reviwed
International conference proceedings, English

Lubrication Characteristics of Deep Drawing with High-pressured Water Jet
Takashi Kuboki; Hiroshi Saito; Yuta Tanaka; Makoto Murata; Kazumi Matsui; Makoto Tsubokura
Lead, Metal forming, 355-358, Sep. 2012, Peer-reviwed
International conference proceedings, English

Prediction of Stress-strain Diagram from Forming Load in Stretch Forming
Takashi Kuboki; Yingjun Jin; Makoto Murata
Lead, International Journal of Mechanical Sciences, 60, 46-53, Jun. 2012, Peer-reviwed
Scientific journal, English

Development of a Tube-Spinning Machine for Thin Tubes with a Large Diameter
Takashi Kuboki; Kazuhito Takahashi; Kazuhiko Sanda; Susumu Moriya; Keisuke Ishida
Lead, MATERIALS TRANSACTIONS, JAPAN INST METALS, 53, 5, 853-861, May 2012, Peer-reviwed, Manufacturing of thin tube with a large diameter could be a target of tube spinning. This kind of tube could be used as a casting mould for optical films and laminate films which protect IC cards. In the present research, a new machine has been developed in order to manufacture stainless steel tubes with a thin thickness of 0.2 mm and a very large diameter of 500 mm. Deformation in tube spinning for a small diameter of 30 mm was examined using a conventional spinning machine for thin tubes with small diameters. The examined characteristics of deformation include effect of initial thickness deviation and indentation on dimensional precision of formed tubes. Based on the examination in the conventional machine, a new tube-spinning machine was designed and the spinning conditions were determined, and the machine has successfully deformed parent tubes into thin tubes with a large diameter. [doi: 10.2320/matertrans.MF201104]
Scientific journal, English

A5083厚板の曲げ加工におけるスプリングバックに及ぼす曲げ型形状の影響
ハムタ・ナランバータル; 村田眞; 久保木孝; 柴田隆浩; アマダ; 金英俊; 株)アマダ
日本塑性加工学会論文誌/塑性と加工, 第53, 615, 74-78, Apr. 2012, Peer-reviwed
Scientific journal, Japanese

Effects of Punch and Die Parameter on Spring-back at Bending Process of Thick Sheet A5083
Naranbaatar Khamt; Makoto Murata; Takashi Kuboki; Takahiro Shibata; Yingjun Jin
Journal of Japan Society of Technology for Plasticity, 53, 615, 362-366, Apr. 2012, Peer-reviwed
Scientific journal, Japanese

High-Accuracy Bending with Force Control
柴田 隆浩; 金 英俊; 小山 純一; 久保木 孝; 村田 眞
Journal of Japan Society of Technology for Plasticity, 53, 612, 64-68, Jan. 2012, Peer-reviwed
Scientific journal, Japanese

Control of Bending Radius in Incremental Beinding Process of Very Thin Sheet metals
S.Hama; T.Kuboki; M.Murata
Corresponding, Proc.10th INt.Cnf.Techn.Plast,ICTP2011, 1132-1135, Sep. 2011, Peer-reviwed
International conference proceedings, English

Development of a Tube-spinning Machine for Thin Tubes with a Large Diameter
Takashi Kuboki; Makoto Murata; Kazuhito Takahashi; Kazuhiko Sanda; Susumu Moriya; Keisuke Ishida
Lead, Tubehydro 2011, 191-194, Jul. 2011, Peer-reviwed
International conference proceedings, English

Suppression of Flatness in Circular Tube-draw Bending by Applying Side Compression
Kazuhito Takahashi; Takashi Kuboki; Makoto Murata
Corresponding, Tubehydro 2011, 125-128, Jul. 2011, Peer-reviwed
International conference proceedings, English

Effect of Feeding Velocity on Formability in a New Micro-Drawing Process Using a Pair of Concave Rolls
Takashi Kuboki; Yasunori Senzaki; Makoto Murata
Lead, ICOMM 2011, 279-284, Mar. 2011, Peer-reviwed
International conference proceedings, English

SPRING-BACK PREDICTION BY COMBINATION OF THE FINITE ELEMENT ANALYSIS AND BENT-BEAM THEORY CONSIDERING BAUSCHINGER EFFECT
Toru Matsumoto; Shinntarou Gotoh; Takashi Kuboki; Makoto Murata; Yingjun Jin
Corresponding, COMPUTATIONAL PLASTICITY XI: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 126-134, 2011, Plate bending is a common plastic working. High-precision bending would require the accurate prediction of spring-back, which is affected by Bauschinger effect. In the present study, an analysis of spring-back prediction was conducted by a combination of the finite element method (FEM) and bent-beam theory. The characteristic of this analysis is that the FEM is used to analyze bending behaviour and the bent-beam theory is used to predict spring-back. This combination would reduce calculation time and skip the identification procedure of parameters which is needed in conventional phenomenological approach. The proposed method predicted spring-back more accurately than conventional analysis without kinematic hardening. Futhermore, the proposed numerical method was able to conduct analysis as accurate as that by the conventional FEM, which is implemented with numerical description of kinematic hardening, within much shorter calculation time.
International conference proceedings, English

Application of Homogenization Method Considering Crystal Plasticity for Prediction of Mechanical Properties for Copper and Low Carbon Steel
Takuya Sueoka; Takashi Kuboki; Makoto Murata; Kouichi Kuroda; Kenjiro Terada
Corresponding, COMPUTATIONAL PLASTICITY XI: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 603-609, 2011, The homogenization method considering crystal plasticity was taken as a prediction method of mechanical properties after metal forming Copper and low carbon steel were taken as raw materials It was experimentally clarified that low carbon steel showed stronger Bauschinger effect than copper At the first trial of analysis, the homogenization method considering crystal plasticity showed a similar behavior to that of copper of single phase metal rather than low carbon steel However, addition of small amount of carbide in low carbon steel inside the crystals, just as in the actual steel, significantly improved the prediction accuracy.
International conference proceedings, English

EFFECT OF TEMPERATURE IN FORMABILITY OF COMPOSITE COMPOSED OF OVERLAPPED FIBRE BUNDLE, THERMOPLASTIC RESIN AND METAL
Takashi Kuboki; Shun-Ichi Uematsu; Makoto Murata
Corresponding, COMPUTATIONAL PLASTICITY XI: FUNDAMENTALS AND APPLICATIONS, INT CENTER NUMERICAL METHODS ENGINEERING, 80-90, 2011, A structure for a composite of fibre-metal laminate (FML) has been proposed, which is composed of reinforcing fibre bundles, thermoplastic resin as the matrix and metal plates. The reinforcing fibre bundles are discontinuous, and are intentionally overlapped in the longitudinal direction. The resin including fibre bundles was sandwiched between the metal plates. The application concept for the industry is composed of three stages. At the 1st stage, FML is fabricated by lamination of reinforcing fibre bundles, thermoplastic resin and metal plates. At the 2nd stage, FML is formed into the final shape of the product by secondary forming processes, such as stretching or bending under a heated condition which melts the thermo resin. At the 3rd stage, the formed product is expected to have high strength. In the present paper, the effect of heating temperature on the deformation of FML at the 2nd stage was clarified. Firstly, the numerical examination was shown on the effect of overlap length on the fracture mode and the reinforcing mechanism in the proposed FML. Based on the result, the minimum bare length for the overlapped part for the discontinuous fibre bundles was determined so that the tensile strength might be as high as that with FMLs with continuous fibre bundles at the 3rd stage. Finally actual FML was experimentally fabricated, and subjected to all though the 1st to 3rd stages to verify the efficiency of the FML. In particular, the effect of heating temperature was focused upon to realize the forming process at the 2nd stage.
International conference proceedings, English

Comparison of cutting forces and cut surfaces between new shearing method with horizontal tool movement and conventional shearing
Datao Lu; Makoto Murata; Takashi Kuboki; Yingjun Jin
Keikinzoku/Journal of Japan Institute of Light Metals, 61, 3, 100-106, 2011, Peer-reviwed, Sheet metal cutting is a general metal forming. A new shearing method has been invented for sheet metal cutting by authors. It has been named MM shearing. Sheet metal is cut by vertical movement of the tool for conventional shearing. In contrast, sheet metal is cut by horizontal movement of the tool for MM shearing. There are several advantages in MM shearing, for example small and inexpensive tools are applicable. There are some important parameters in the MM shearing, such as tool angle, clearance between the tool and die, sheet thickness, cutting speed and so on. In this paper, a series of experiments were carried out to compare MM shearing, conventional shearing and repetitive vertical shearing. The cutting force and cut surface were discussed in the various shearing methods. For MM shearing, the effect of clearance, sheet holding method, scrap width and cutting velocity on cutting force were also discussed. As a result, characteristics of MM shearing method were clarified.
Scientific journal, Japanese

Effect of clearance on new shearing method with horizontal tool movement of 1100 aluminum sheet
Datao Lu; Makoto Murata; Takashi Kuboki; Yingjun Jin
International Journal of Advanced Manufacturing Technology, Springer London, 57, 5-8, 647-653, 2011, Peer-reviwed, Sheet metal cutting is a general metal forming process. A new cutting method has been invented for sheet metal by the authors. It has been named the MM-shearing method. There are several advantages in the method, for example small cutting force, beautiful cutting surface and no burrs on the cut surface. Moreover, the equipment used in the method is inexpensive. However, there are some important parameters to consider in the MM-shearing method, such as tool angle, clearance between the tool and die, sheet thickness, and cutting speed. In this paper, a series of experiments was carried out to examine the suitable clearance. The experimental material is 1100 aluminum sheet (Japanese Industrial Standard). The cutting force, ratio of sheared and fractured surfaces, inclination angle, burr height, roughness, and Vickers hardness of the cutting surface are examined corresponding to the clearance change. The principle and characteristics of the MM-shearing method are made clear in this paper in terms of the clearance between the tool and die. © 2011 Springer-Verlag London Limited.
Scientific journal, English

An analytical method of metal forming considering ageing in the microstructure for carbon steel
Takashi Kuboki; Makoto Murata; D. R. J. Owen
Lead, COMPUTERS & STRUCTURES, PERGAMON-ELSEVIER SCIENCE LTD, 88, 19-20, 1162-1178, Oct. 2010, Peer-reviwed, An analytical method is proposed that considers ageing, with an emphasis on cementite morphology, for metal forming simulations. The basic concept is that ageing in the microscale and the deformation and temperature rise in the macroscale should be analysed simultaneously. In the macroscale, mechanical analysis is carried out followed by thermal analysis. In the microscale, the diffusion of carbon is estimated considering the history of strain and temperature analysed by the macroscale analyses. Using the proposed method, metal forming analysis is conducted and experimental verification is conducted with emphasis on carbon content and deformation rate. (C) 2010 Elsevier Ltd. All rights reserved.
Scientific journal, English

Deformaiton by V-bending of Thick Plate Matal 5083
Naranbaatar Khamt; Makoto Murata; Takashi Kuboki
Proc. of The 12th International Conference on Aluminum Alloys, 619-624, Sep. 2010, Peer-reviwed
International conference proceedings, English

Influence of Initial Thickness of Circular Tube in Rotary-Draw Bending Adding Axial Pushing Force for Suppression of Flatness
Kazuhito Takahashi; Takashi Kuboki; Makoto Murata; Kouzo Yano
STEEL RESEARCH INTERNATIONAL, WILEY-V C H VERLAG GMBH, 81, 9, 580-583, Sep. 2010, Peer-reviwed, The tube bending process adding the axial pushing force has been suggested by researchers and engineers for suppression of flatness that is the defective phenomenon of bent tubes. The authors have been considering in previous research works the mechanism of the suppression of flatness and confirm that the flatness was successfully suppressed by the axial pushing force with sufficient pressure die force by using steel tube. When the bending radius R-0 is larger than 2.5 times of diameter d(0), the flatness can be suppressed under 3.0%. However, the effect that the difference of the initial thickness of tube in this process method is not clarified. Therefore, in the present research, FEM and experiments were conducted by changing the initial thickness of the STK590 (JIS) tube from 2.0 to 3.2 mm for a diameter of 27.2 mm. As a result, when the axial pushing force is over 215 MPa while the initial thickness is between 2.3 and 3.2 mm, buckling occurs. When the axial pushing force is over 143 MPa while the initial thickness is 2.0 mm, wrinkle occurs and it is the limit of processing. However, when the initial thickness of circular tube is between 2.3 and 3.2 mm while the axial force is 143 MPa, the flatness could be suppressed within 4.0% for any thickness.
Scientific journal, English

FEM Analysis of Tube Straightener Adopting Implicit Scheme
Takashi Kuboki; He Huang; Makoto Murata; Yohei Yamaguchi; Kouichi Kuroda
STEEL RESEARCH INTERNATIONAL, WILEY-V C H VERLAG GMBH, 81, 9, 584-587, Sep. 2010, Peer-reviwed, Straightening is an important process, which is positioned at the very end of production lines in industry. Straightening determines the final shape in longitudinal direction and cross section as well as the distribution of residual stress. In particular, rotary straightener is an effective method with high productivity for long products of bar rods and tubes. The working conditions for the rotary straightener are usually determined based on the interpretation of technicians in practical production lines. In the present research, a complete FEM model, named "Trial 3", was built up adopting the implicit scheme for the purpose of precise estimation of tube straightening in three-stand straightener. Four types of modeling were tried overall and comparison was made. While Trial 1, 2 and 3 adopted the implicit scheme, Trial 4 adopted the explicit scheme. In Trial 3 of complete model, all the rolls are reproduced and no prescribed displacements are assigned just as actual straightening. Trial 4 of explicit scheme has the same setting to Trial 3. Trial 4 of explicit scheme showed poor results and stress and strain histories are quite different from those in the other models. Trial 1, 2 and 3 have shown similar results except a phenomenon whereby only Trial 3 shows axial shrinkage and radial expansion.
Scientific journal, English

Computational Method of Springback in V-bending of Sheet Having Bausching Effect
Kazunari Imai; Jin Yingjun; Hiroki Tsuruta; Junichi Koyama; Takashi Kuboki; Makoto Murata
STEEL RESEARCH INTERNATIONAL, WILEY-V C H VERLAG GMBH, 81, 9, 757-760, Sep. 2010, Peer-reviwed, The final bending angle by a press brake equals the sum of clamp and springback angles. Hence, the on-line measurement of the clamping angle and prediction of springback are key technologies for the precision bending. Recently, a precise angle sensor for the measurement of clamp angle has been developed, and implemented into bending machines for the on-line measurement. If the springback is known a priori, the required clamp angle can be calculated and the clamping position can be decided using a feedback control system with the precise angle sensor. As a result, a high-accuracy V-bend process becomes possible. In this research, a new computational method, based on fundamental bending theory, is proposed for the prediction of springback. However, errors will arise if the material anisotropy or the Bauschinger effect in springback are not accounted for. For the consideration of the Bauschinger effect, a new method is introduced in the fundamental analysis. First, a series of tension tests are conducted for the investigation of the Bauschinger effect for various values of pre-strain and different material types. Based on these results, a new empirical equation is proposed for the description of the Bauschinger effect. The empirical equation is combined with the fundamental bending theory to improve the calculation accuracy of the springback, followed by experimental verification. This method makes it possible to reduce the error margin of springback to less than 0.5 degree with a computing time of about one second and can also be easily implemented on the filed.
Scientific journal, English

Effect of Initial Thickness Deviation on Deformed Tube Shape in Tube Spinning
Takashi Kuboki; Naoto Takahashi; Kazuhito Takahashi; Kazuhiko Sanda; Susumu Moriya; Keisuke Ishida; Makoto Murata
STEEL RESEARCH INTERNATIONAL, WILEY-V C H VERLAG GMBH, 81, 9, 978-981, Sep. 2010, Peer-reviwed, Tube spinning, or flow forming, is an effective and stable method for manufacturing thin-film metal tubes, which are used as steel belts for precision conveyers, printing rollers in printers and in flexible photovoltaic film batteries. The original substrate tubes for spinning are manufactured by plastic-deformation processes, such as deep drawing and ironing. Due to instability in the previous forming, thickness deviation must inevitably exist initially. In the present research, examination was conducted with the focus upon the effect of initial thickness on the precision of tubes. As a result of a series of experiments, it is clarified that the thickness-deviation ratio of deformed tube is slightly larger than initial ratio in tube spinning with a flexible mandrel. It is also noteworthy that the initial thickness deviation causes the warpage along the tube axis. Therefore, it is concluded that initial thickness deviation should be reduced as little as possible for the precision tube spinning. Furthermore, numerical analyses were carried out to clarify the mechanism of initial thickness effect.
Scientific journal, English

Mechanical properties of wire drawn by a new drawing process using a pair of concave rolls
Takashi Kuboki; Kazumichi Aoki; Yasunori Senzaki; Makoto Murata
In-Tech 2010, 133-136, Sep. 2010, Peer-reviwed
International conference proceedings, English

Effect of Tool Angle on New Shearing Method of 1100 Aluminium Sheet
Datao Lu; Makoto Murata; Takashi Kuboki; Yingjun Jin
Proceedings of the 12th International Conference on Aluminium Alloys, 548-553, Sep. 2010, Peer-reviwed
International conference proceedings, English

Deformation Behavior of Joining Tube and Holed Rib by Extrusion
Tsutomu Moroi; Takashi Kuboki; Makoto Murata
Proceedings of the 12th International Conference on Aluminium Alloys, 589-594, Sep. 2010, Peer-reviwed
International conference proceedings, English

Processing Limit in V-bending
Takahiro Shibata; Yingjun Jin; Junichi Koyama; Takashi Kuboki; Makoto Murata
Proceedings of the 12th International Conference on Aluminium Alloys, 613-618, Sep. 2010, Peer-reviwed
International conference proceedings, English

Naranbaatar Khamt, Makoto Murata, Takashi Kuboki, Takahiro Shibata, Yingjun Jin
Deformation by; V-bending of Thick Plate Met
Proceedings of the 12th International Conference on Aluminium Alloys, 619-624, Sep. 2010, Peer-reviwed
International conference proceedings, English

Composite structure composed of overlapped fibre bundles, thermoplastic resin
Takashi Kuboki; Shun-ichi Uematsu; Makoto Murata
Composites Science and Technology, 70, 9, 1338-1345, Jun. 2010, Peer-reviwed
Scientific journal, English

Deformation in V-bending of aluminum alloy 5083 plate
Khamt Naranbaatar; Makoto Murata; Takashi Kuboki; Takahiro Shibata; J. I N Yingjun
Keikinzoku/Journal of Japan Institute of Light Metals, 60, 6, 264-268, Jun. 2010, Peer-reviwed, Bending is a fundamental common process, which has been applied in industry for hundreds of years. There are many research works on bending process for thin sheet metal with thickness of 3 mm or less, which is used as components for various products. On the other hand, bending process for plate has also been applied according to the diversity of market needs, but only for special usage. Therefore, only a few research works have been presented and the expertise is still limited. Ogawa shows some examination results, those are able to control deformation of sheet by changing die open width and punch radius of sheet metal bending up to 6 mm thickness. In the present research, experimental examination is carried out with emphasis on the effect of the die open width on the bending behavior of thick plate with 10 mm thickness: deformation in the ridge line direction, spring-back and deduction of total length. As a result, it is quantitatively clarified that the die open width has some amount of effect on the unique phenomena in plate bending such as saddle type deformation, reduction of bending curvature from the punch radius and the deduction discrepancy from theoretical value.
Scientific journal, Japanese

板材のL曲げ加工におけるパンチの軌跡半径の影響
小山純一; 金英俊; 今井一成; 久保木孝; 村田眞
日本塑性加工学学会誌「塑性と加工, 50, 586, 57-61, Nov. 2009, Peer-reviwed
Scientific journal, Japanese

Effect of Punch Track Radius on Mechanism of L-bending of Sheet Metal
unichi Koyama; Yingjun Jin; Kazunari Imai; Takashi Kuboki; Makoto Murata
J. of Japan Society of Technology for Plasticity, 50, 586, 1029-1033, Nov. 2009, Peer-reviwed
Scientific journal, Japanese

Feasibility Study by Finite Element Analysis on Free Size Drawing Using a Pair of Concave Rolls
Takashi Kuboki; Yasunori Senzaki; Makoto Murata
COMPLAS X, 447-450, Sep. 2009, Peer-reviwed
International conference proceedings, English

Analysis of Residual Stress in Carbon Steel after Localized Heating
Takashi Ito; Makoto Murata; Takashi Kuboki; Yingjun Jin
COMPLAS X, 505-508, Sep. 2009, Peer-reviwed
International conference proceedings, English

Effect of Pre-strain history on mechanical characteristics in Aluminium 1070
Jun-ichi Oguri; Takashi Kuboki; Makoto Murata; Kenjiro Terada
COMPLAS X, 509-512, Sep. 2009, Peer-reviwed
International conference proceedings, English

Finite Element Analysis and Experimental Investigation on Circular Tube-Pure Bending
Kazuhito Takahashi; Takashi Kuboki; Makoto Murata
Tubehydro 2009, 188-193, Sep. 2009
International conference proceedings, English

Effect of tube wall thickness in Joining of Aluminum Tube and Holed Rib by Extrusion
Tsutomu Moroi; Takashi Kuboki; Makoto Murata
Key Engineering Materials, 424, 121-128, Sep. 2009, Peer-reviwed
Scientific journal, English

凹型ロールを用いた伸線加工におけるクラッシュと張力が減率に及ぼす影響
久保木孝; 仙崎泰慎; 村田眞; 中村友彦
日本塑性加工学学会誌「塑性と加工」, 第50, 582, 60-64, Jul. 2009, Peer-reviwed
Scientific journal, Japanese

凹型ロールを用いた伸線加工におけるクラッシュと張力が減径率に及ぼす影響
久保木孝; 仙崎泰慎; 村田眞; 中村友彦
塑性と加工, The Japan Society for Technology of Plasticity, 7, 50, 650-654, Jul. 2009, Peer-reviwed, In recent years, forming processes of ultrafine and precise products have been playing a key role in the enhancement of the performance and functions of machines and equipment. In particular, ultrathin wire is expected to be used as a material with versatile functions. Wire drawing using hole dies has conventionally been used in the manufacture of thin and ultrathin wires. In thin conventional drawing, dozens of dies with specified hole diameter corresponding to each target diameter of wires are needed. Moreover, in the recent trend of miniaturizing dimensions, the die itself would be difficult to manufacture. In this research, a new wire-drawing method without a die is proposed. The proposed method has a similar machine composition to two roll straighter, i.e. wire is deformed between two skewed rolls. A series of finite element analysis was carried out to examine the suitable roll profile and the effect of crash and tension on the reduction in wire diameter. On the basis of the analysis, a prototype machine was designed and used to verify the efficiency of the new method. Results showed that an 11% reduction in diameter was achieved under optimum condition.
Scientific journal, Japanese

EFFECT OF SHAPE OF DIE ON FORMING LIMIT IN ROTARY NOS-ING WITH RELIEVED DIE
Takashi Kuboki; Atsushi Kominami; Yusuke Ohde; Makoto Murata
The 4th India-Japan Joint Seminar, 109-116, Mar. 2009
International conference proceedings, English

回転引曲げ加工における円管の軸押し力によるへん平抑制
高橋和仁; 渡邊峻士; 久保木孝; 村田眞; 小野数彦; 矢野巧造
日本塑性加工学学会誌「塑性と加工」, 49, 572, 66-72, Sep. 2008, Peer-reviwed
Scientific journal, Japanese

New Cutting Method for Sheet Metal
Akinori Tanaka; Makoto Murata; Takashi Kuboki; Jin Yingjun
Proceedings of 12th International Conference on Metal Forming，METAL FORMING 2008, 1, 112-118, Sep. 2008
International conference proceedings, English

Formability of A1050 Aluminum Tubes with Different Thickness in Shear Bending Process
Mohammad Goodarzi; Takashi Kuboki; Makoto Murata
Proceedings of 12th International Conference on Metal Forming，METAL FORMING 2008, 79, 233-240, Sep. 2008, Peer-reviwed
International conference proceedings, English

Effect of Temperature on Tube Extrusion and Joining Holed Rib
Tsutomu Moroi; Takashi Kuboki; Makoto Murata
Proceedings of 12th International Conference on Metal Forming，METAL FORMING 2008, 79, 677-684, Sep. 2008, Peer-reviwed
International conference proceedings, English

Effect of Shape of Die on Forming Limit in Rotary Nosing with Relieved Die
Takashi Kuboki; Atsushi Kominami; Yusuke Ohde; Makoto Murata
Proceedings of 12th International Conference on Metal Forming，METAL FORMING 2008, 79, 137-144, Sep. 2008, Peer-reviwed
International conference proceedings, English

Reduction in Flatness Using Axial Compressive Force in Rotary Draw Bending of Circular Tube
Kazuhito Takahashi; Takashi Watanabe; Takashi Kuboki; Makoto Murata; Kazuhiko Ono; Kouzou Yano
J. of Japan Society of Technology for Plasticity, 49, 572, 896-900, Sep. 2008, Peer-reviwed
Scientific journal, Japanese

Joining of 1050 aluminum circular tube and holed rib by extrusion
Tsutomu Moroi; Takashi Kuboki; Yasunori Senzaki; Makoto Murata
Keikinzoku/Journal of Japan Institute of Light Metals, 58, 6, 246-250, Jun. 2008, Peer-reviwed, Tubes that have the rib internally are used as car parts, for example, structural component, radiator, shock absorbers, and so on. The existence of some holes at the rib enhances the function and value of the tubes. But, the tube with holed rib can not be formed by conventional extrusion. Then, we propose a method that extrudes with a ready made rib. The rib is a machined sheet metal with holes. While the tube is extruded, the rib is fed through a slit of mandrel. Tube and sheet are joined at the same time during extrusion. The mandrel has slit and guide. A guide position h that is a distance from die surface to front edge of the guide is a dominant parameter in this research. When guide position h is controlled, metal flow can be adjusted. We carried out an experiment to clarify the effect of guide position on joining by using A1050. Then, a tensile test clarified that joining strength between tube and rib is 40% of base material. Moreover, flatness was observed in measuring the outside diameter and the inside diameter of the tube.
Scientific journal, Japanese

Effect of plug on levelling of residual stress in tube drawing
Takashi Kuboki; Keigo Nishida; Tomohiro Sakaki; Makoto Murata
Journal of materials processing technology, 204, 1, 162–168-168, Jun. 2008, Peer-reviwed
Scientific journal, English

平板の面内逐次打点曲げにおける打撃角度の影響
金英俊; 小山純一; 久保木孝; 村田眞
塑性と加工, 49, 569, 579-583, Jun. 2008, Peer-reviwed
Scientific journal, Japanese

Effect of hardening exponent on tube bending
M. Murata; T. Kuboki; K. Takahashi; M. Goodarzi; Y. Jin
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 201, 1-3, 189-192, May 2008, Peer-reviwed, There are more than 10 kinds of bending, for example press bending, stretch bending, stretch draw bending and others. There are many studies about characteristics of tube bending. But there is no study about the effects of tubular material property on bending. Therefore, we try to examine the effect of material property about hardening exponent on tube bending. Bending radius, strain distribution, springback and flatness of tube are examined on press bending by FEM (finite element method) and experimental results. The results are about the effects of tubular material property such as hardening exponent n. The effect of hardening exponent is clear in the tube bending in the study. The hardening exponent n does not have an effect on springback, thickness strain distributions and flatness ratio at the same bending radius of same tube dimension. (C) 2008 Published by Elsevier B.V.
Scientific journal, English

Improvement of forming limit by rotary nosing with a relieved die
T. Kuboki; Y. Ohde; M. Murata
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE, PROFESSIONAL ENGINEERING PUBLISHING LTD, 222, 2, 245-253, Feb. 2008, Peer-reviwed, Rotary nosing with 'relieved die' is proposed for the shrinking tip diameter of a tube. Press nosing or spinning is conventionally used for shrinking the tip diameter. In press nosing, while the forming limit is low, productivity is high. In spinning, although the forming limit is very high, the productivity is very low. The present proposed rotary nosing is an intermediate method that is expected to achieve a higher forming limit than press nosing and realize higher productivity than spinning. In this present research, the forming limit was first examined experimentally and the mechanism was studied by finite element analysis. Based on the results, rotary nosing with a relieved die was proposed. The relieved die consists of three partial cones so that the die geometry is easily cut out using an ordinary lathe. This type of die can be easily and widely applied for industrial use. The effect of the proposed method was numerically evaluated with regard to the pushing force and hoop stress. Finally, the effect of rotary nosing was verified experimentally and the range was clarified where rotary nosing has a higher forming limit than conventional press nosing.
Scientific journal, English

NEW CUTTING METHOD FOR SHEET METAL
Akinori Tanaka; Makoto Murata; Takashi Kuboki; Jin Yingjun
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 112-118, 2008, Peer-reviwed, Sheet metal cutting is a general metal forming. A new flexible cutting method has been invented for sheet metal by authors. It has been named MM-shearing method. There are several advantages in the method, for example small cutting force, beautiful cutting surface, no burry on the cutting surface, high cutting speed and low cost for cutting production. Moreover, the cutting speed is high, and the equipment based on the method is inexpensive. A prototype experiment is made and experimental sheet metal cutting is examined at some forming conditions. The clearance C(1) is constantly 0. 1 mm between the tool and holding dies. Material of sheet metal is SPCC (Japanese Industrial Standard). The cutting force, ratio of sheared and fracture surfaces, roughness and burry height on the cutting surface are examined experimentally. The tool angle alpha is the most important cutting condition and must be from alpha = 20 to 35degrees. The principle and characteristic of MM-shearing method are made clear in terms of the tool angle in this paper.
Scientific journal, English

EFFECT OF SHAPE OF DIE ON FORMING LIMIT IN ROTARY NOSING WITH RELIEVED DIE
Takashi Kuboki; Atsushi Kominami; Yusuke Ohde; Makoto Murata
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 137-144, 2008, Rotary nosing with "relieved die" was proposed for shrinking the tip diameter of tube, and the effect of surface number on the forming limit was examined. In rotary nosing, either the "relieved die" or the tube is rotated and they are pushed into each other. "Relieved die" consists of working surfaces and relief surfaces. One of the unique points of "relieved die" in this research is that the working surfaces and relief surfaces connect smoothly. In this present research, a series of numerical analyses and experiments were carried out to determine the optimum conditions to suppress defects. The forming limit in conventional press nosing was first examined experimentally taking aluminium alloy A6063 as an example, and the mechanism was studied by finite element analysis. Based on the results, rotary nosing with "relieved die" was introduced. The effect of the number of working surfaces and total contact angle on deformation was examined by numerical analysis, and the optimum die geometry was determined by experiments. As a result, it was revealed that rotary nosing with "relieved die" had a remarkable effect of improving the forming limit compared to conventional press nosing.
Scientific journal, English

COMPUTATIONAL METHOD FOR CALCULATION OF FLANGE DIMENSION IN V-BENDING
Kazunari Imai; Junichi Koyama; Jin Yingjun; Makoto Murata; Takashi Kuboki
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 194-200, 2008, Peer-reviwed, Various V-bending systems have been proposed. Most research works produced so far have dealt with the bending angle, especially the spring-back angle. In a plant, both the bending angle and flange dimension are important for the high accuracy of the sheet metal products. In this research, a new computational method for prediction of flange dimension is proposed in order to realize high precision V-bending. This method based on fundamental bending theory is able to predict both bending shape before and after spring-back, and also able predict a length of bent sheet metal along the neutral axis. Therefore, it does not need a large amount of experimental data. The calculation result is corresponding to the experiment value. Moreover, the computation speed is fast enough for real time use in actual machine. Therefore, the proposed method can realize high precision bending and has been successfully adopted in actual operation.
Scientific journal, English

INFLUENCE OF PAD TIP RADIUS ON L BENDING OF SHEET METAL
Junichi Koyama; Yingjun Jin; Kazunari Imai; Makoto Murata; Takashi Kuboki
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 209-216, 2008, Peer-reviwed, In the sheet metal working process, the accuracy of the bending angle and flange length have a significant influence on the product quality. Hence, it is necessary to accurately predict spring back and elongation of the sheet metal. This paper describes a 2D finite element model used for characterizing a new L bending process. Because both spring back and spring forward exist, it is difficult to predict the bending angle. The effects of pad tip radius on bending force, bending radius, elongation, spring back and spring forward were investigated. Moreover, the new L bending mechanism was clarified.
Scientific journal, English

FORMABILITY OF A1050 ALUMINUM TUBES WITH DIFFERENT THICKNESS IN SHEAR BENDING PROCESS
Mohammad Goodarzi; Takashi Kuboki; Makoto Murata
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 233-240, 2008, Peer-reviwed, Tube shear bending is an effective technology for the production of compact and unified bent tubular parts through cold metal forming. In order to perform a successful forming, an appropriate pushing force must be applied on the tube during the shear bending process. In this paper, the effect of the initial thickness on formability of A1050 circular aluminum tubes is investigated. Both experiment and numerical simulation indicate that increasing the initial thickness enhances the wrinkling resistance of the tube. A simple evaluation of the deformation energy shows that the thicker the tube wall is, the lower the buckling tendency is. A series of experiments were performed using tubes with different wall thickness and applying various pushing pressures. Experimental results demonstrate that the forming limit of shear bending spreads with the increment of the tube's initial thickness. The applicable range of the pushing pressure, which realizes the shear deformation without any defects, will be expanded by employing a thicker tube.
Scientific journal, English

SUPPRESSION OF FLATNESS IN TUBE-DRAW BENDING BY APPLYING SUITABLE AXIAL COMPRESSIVE FORCE ACCORDING TO BEND RADII
Kazuhito Takahashi; Takashi Kuboki; Makoto Murata; Kazuhiko Ono; Kouzou Yano
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 241-248, 2008, Peer-reviwed, One of the defects of bent tube is flatting. Several methods have been suggested and adopted in order to suppress the flatness of bent tube. Among them, insert of mandrel is an effective method to prevent the tube from flatting. However, the mandrel is not always be applicable because of cost inefficiency or complexity of tube geometry. The objective of this paper is to present a valid method in rotary draw bending that can prevent the flatness by applying suitable axial compressive force according to bending radii. A prototype machine was used to control the axial compressive force and to find the effect of the axial force on the flatness under to various conditions of bending radii. Ordinary medium carbon steel, STK490, was select as tube material. The radius of bending die was from one to three times of tube-outer diameter.
Scientific journal, English

EFFECT OF TEMPERATURE ON TUBE EXTRUSION AND JOINING HOLED RIB
Tsutomu Moroi; Takashi Kuboki; Makoto Murata
STEEL RESEARCH INTERNATIONAL, VERLAG STAHLEISEN MBH, 79, 677-682, 2008, Peer-reviwed, Wall thickness and cross section shape are constant in the axial direction when aluminum tubes are formed by conventional extrusion process. Tubes with internal ribs have high strength in comparison with those without ribs. These tubes can be used, for example, as structural parts, heat sinks, and impact absorbers. The existence of some holes at ribs enhances the function and value of the tubes. The appropriate positioning of holes at ribs reduces the weight of structural parts without strength reduction. In the case of heat sinks, holes change the fluid flow and would realize effective heat transfer.
A new method has been proposed by the authors for extrusion of a tube joined with pre-holed rib. The unique point is that guides are used to control the metal flow for Joining the rib. Hence, the guide position and extrusion temperature are important parameters. In this present research, the effect of these parameters on joining strength and extruded shape is clarified experimentally.
It is revealed that joining strength increases with temperature and guide position. The effect of holes on the deformation of the rib is also investigated and it was found that pre-holed rib tends to buckle due to low rigidity compared to non-holed rib.
Scientific journal, English

A new extrusion method joining tube and sheet with holed rib
Tstomu Moroi; Takashi Kuboki; Makoto Murata
JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY, KOREAN SOC MECHANICAL ENGINEERS, 21, 10, 1548-1552, Oct. 2007, Peer-reviwed, Wall thickness is constant in the axial direction when aluminum tubes are formed by conventional extrusion process. Tubes with internal ribs have high strength in comparison with those without ribs. These tubes can be used, for example, as structural parts, heat sinks, and impact absorbers. The existence of some holes at ribs enhances the function and value of the tubes. The appropriate positioning of holes at ribs reduces the weight of structural parts without strength reduction. In the case of heat sinks, holes change the fluid flow and would realize effective heat transfer. In this research, a new extrusion method is proposed by authors for manufacturing tubes with holed ribs. A new extrusion method is applied by FEM analysis. Model experiment was carried out based on the results. The method involves the use of a unique mandrel that has a slit along its axis and two guides at the slit exit. A holed sheet is fed through the slit and joined to the inner surface of the tube. In particular, the effect of the guide height is clarified in this study.
Scientific journal, English

Effect of die corner radius on the formability and dimensional accuracy of tube shear bending
Mohammad Goodarzi; Takashi Kuboki; Makoto Murata
International Journal of Advanced Manufacturing Technology, 35, 35, 66–74-74, Oct. 2007, Peer-reviwed
Scientific journal, English

Thickness Optimization of Axisymmetric Tube Extruded by a New Method Using Tapered Mandrel
Takashi Kuboki; Takahiro Makiyama; Makoto Murata
Computational Plasticity / COMPLAS 9th, 370-373, Sep. 2007, Peer-reviwed
International conference proceedings, English

Precise Control of Thickness in New Tube-Extrusion Method with Tapered Mandrel
Takashi Kuboki; Takahiro Makiyama; Makoto Murata
2nd International Conference on New Forming Technology, 145-155, Sep. 2007, Peer-reviwed
International conference proceedings, English

Characteristics of Tube Bending by MOS Bending Machine
Makoto Murata; Takashi Kuboki; Kazuhito Takahashi
2nd International Conference on New Forming Technology, 135-144, Sep. 2007, Peer-reviwed
International conference proceedings, English

Effect of initial thickness on shear bending process of circular tubes
M. Goodarzi; T. Kuboki; M. Murata
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 191, 1-3, 136-140, Aug. 2007, Peer-reviwed, Tube shear bending is a suitable technology to realize considerable small bending radii, which is very difficult to be achieved through common cold-bending processes. The authors have investigated the tube shear bending process experimentally. Moreover, an elasto-plastic 3D finite 14 element simulation has been conducted aiming to analyze the forming process. In this paper, the effects of the initial thickness on the deformation characteristics of the tube shear bending have been investigated both by experiments and numerical simulation. In order to show the validity of simulation, the FEM results of the thickness strains as well as the cross section configurations of the deformed tube have been compared with the experimental ones. The results indicate that under the effect of same pushing pressure, raising the initial thickness, the tube thinning and cross section deformation increase. (C) 2007 Elsevier B.V. All rights reserved.
Scientific journal, English

Forming behavior of shear bending with mandrel as substitution method of hydroforming
Takashi Kuboki; Mohammad Goodarzi; Makoto Murata
Tube Hydro2007, 115-120, Jun. 2007, Peer-reviwed
International conference proceedings, English

リブに穴を有する管の押出し接合加工
諸井努; 久保木孝; 高岡大和; 村田眞
日本塑性加工学会誌「塑性と加工」, 第48, 554, 62-66, Mar. 2007, Peer-reviwed
Scientific journal, Japanese

リブに穴を有する管の押出し接合加工
諸井努; 久保木孝; 高岡大和; 村田眞
塑性と加工, The Japan Society for Technology of Plasticity, 48, 554, 234-238, Mar. 2007, Peer-reviwed, Tubes with an internal rib have a high strength in comparison with those without a rib. These tubes can be used, for example, as structural parts, heat sinks, and impact absorbers. The existence of some holes at the rib enhances the function and value of the tubes. The appropriate positioning of holes at the rib reduces the weight of structural parts while preserving strength. In the case of heat sinks, holes change the fluid flow and realize effective heat transfer. In this research, a new extrusion method is proposed for manufacturing tubes with a holed rib. The method involves the use of a unique mandrel that has a slit along its axis and two guides at the slit exit. A holed plate is fed through the slit and made into a holed rib of the tube. The flow of the billet is investigated. In particular, the effect of the guide height is clarified in this study.
Scientific journal, Japanese

Deep drawing of 1050 aluminum sheets using high pressure jet water as lubricant
村田眞; 久保木 孝
軽金属学会論文誌, 56, 9, 469-473, Sep. 2006
Scientific journal, Japanese

Effect of Tube Thickness on Shear Bending Process of Circular Tubes
Mohammad Goodarzi; Takashi Kuboki; Murata Murata
Proceedings of Advances in Materials and Processing and Technologies, 327, Aug. 2006, Peer-reviwed
International conference proceedings, English

Ironing on Aluminum Circular Tube to Reduce Weight
M. Murata; T. Kuboki
Proceedings of Advances in Materials and Processing and Technologies, 334, Jul. 2006, Peer-reviwed
International conference proceedings, English

Effect of Plug on Leveling of Residual Stress in Tube Drawing
Takashi Kuboki; Keigo Nishida; Tomohiro Sakaki; Makoto Murata
Proceedings of Advances in Materials and Processing and Technologies, P1052, Jul. 2006, Peer-reviwed
International conference proceedings, English

Thickness optimization of axisymmetric tube by three-dimensional finite-element analysis for high-flexural rigidity
T Kuboki; T Makiyama; M Murata
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, PROFESSIONAL ENGINEERING PUBLISHING LTD, 220, 4, 473-482, Apr. 2006, Peer-reviwed, A numerical method is proposed for optimizing the wall thickness distribution of axisymmetric tube using three-dimensional finite-element method. It is essential to put intermediate nodes between adjustable nodes in the method. Using the proposed method, the wall thickness distributions are optimized to realize high-flexural rigidity under the condition that volume is constant. It is revealed that the constraint condition has significant effect on the optimized geometry. When the end of the tube is constrained completely, it is not necessary to increase the thickness at the end. In contrast, when the end is not constrained, the thickness must be increased substantially. Therefore, it is important to take the constraint condition of the tube into consideration for tube geometry optimization. It is also demonstrated quantitatively that the geometry optimization realizes the volume reduction of the tube from the point of flexural rigidity per volume. Moreover, the feasibility to produce the optimized tube is studied using a unique extrusion method with tapered mandrel, which has been proposed by the authors. In this unique method, the wall thickness is controlled arbitrarily by positioning the tapered mandrel during extrusion.
Scientific journal, English

逐次打点曲げ加工における平板の面内曲げ挙動に及ぼす打撃パンチの影響
金英俊; 村田眞; 久保木孝
軽金属学会 学会誌「軽金属」, 56巻, 3, 145-149, Mar. 2006, Peer-reviwed
Scientific journal, Japanese

逐次打点加工曲げにおける面内曲げ挙動に及ぼす打撃ピッチの影響
金英俊; 久保木孝; 村田眞
塑性と加工, The Japan Institute of Light Metals, 56, 3, 145-149, Mar. 2006, Peer-reviwed, Indentation of punch, beating angle and beating pitch are dominant factors for incremental in-plane bending process. In this paper, the effects of beating pitch on beating force, bending radius and strains in the three directions are clarified by finite element analysis and experiment. The results show that the beating pitch has no effect on bending radius when the actual indentation is same. On the other hand, when the setting indentation is fixed, the beating pitch has an effect on bending radius due to the elastic deformation of punch and the support part. These forming properties of in-plane bending obtained by analysis and experiment had an agreement.
Scientific journal, Japanese

The Effect of Pushing Force on the Shear Bending Process of Circular Tubes
Mohammad Goodarzi; Takashi Kuboki; Makoto Murata
7th International Conference on Technology for Plasticity, 79-80, Oct. 2005
International conference proceedings, English

Simulation for Flat Hemming of Aluminum Sheet Metal
Murata Makoto; Takashi Kuboki
7th International Conference on Technology for Plasticity, 77-78, Oct. 2005
International conference proceedings, English

Tool Design for Suppressing Fracture at the Tip of Tube after Nosing with Die
Takashi Kuboki; Yasuhiko Kimura; Makoto Murata; Takeshi Shimoda
Computational Plasticity / COMPLAS 8th, 599-602, Sep. 2005
International conference proceedings, English

Evaluation Method of Microstructure for Prediction of Ageing Progress in Hypo-eutectoid Carbon Steel
Takashi Kuboki; Akio Miyake; Makoto Murata; Roger Owen
Computational Plasticity / COMPLAS 8th, 978-983, Sep. 2005
International conference proceedings, English

Prediction of static strain hardening progress from cementite morphology in hypo-eutectoid carbon steel
T Kuboki; M Takada; M Murata
MATERIALS SCIENCE AND TECHNOLOGY, MANEY PUBLISHING, 21, 7, 803-812, Jul. 2005, Peer-reviwed, A numerical method is proposed to predict the progress of static strain aging from the cementite morphology in hypo-eutectoid steel in the aging temperature interval from about 473 to 573 K. It is assumed in the approach that strain aging is dominated by the dislocation locking of carbon atoms released during the decomposition of cementite, and that the steel becomes hard in proportion to the amount of diffused carbon atoms in ferrite. Based on scanning electron microscopy images, a finite element mesh was composed, and numerical analyses were carried out in a similar way to heat transfer analysis. As a result, the transfer coefficient of carbon atoms in the ferrite-cementite boundary was estimated compared with experimental results. Moreover, the influence of grain size on strain aging was obtained using the proposed numerical analysis.
Scientific journal, English

テーパマンドレルを用いた変肉押出し加工の有限要素シミュレーション
牧山高大; 久保木孝; 村田眞
日本塑性加工学会，平成17年度 塑性加工春季講演会講演論文集, 87-88, May 2005
Scientific journal, Japanese

Deformation analysis for the shear bending process of circular tubes
M Goodarzi; T Kuboki; M Murata
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 162, 492-497, May 2005, Peer-reviwed, In order to minimize the space of bent tubular parts, a bending technology with small bending radii has been requested recently. Tube shear bending is a suitable technology to realize a considerable small bending radius. In this paper, the procedure of tube shear bending has been introduced. Moreover, an elasto-plastic 3D finite element simulation has been conducted to analyze the forming process. Also the deformation behavior of tube has been investigated. For this purpose, tube strain distribution has been illustrated. The theoretical values of strains have been obtained and compared with the simulated results. In order to show the validity of simulation, the FEM results of tube thickness strain have been compared with the experimental ones. The results of this paper clarify the deformation characteristic of tube during shear bending process. These results demonstrate that the forming process is under a combination of shearing and bending deformations. (c) 2005 Elsevier B.V. All rights reserved.
Scientific journal, English

Influence of strip materials on behavior of incremental in-plane bending
YJ Jin; T Kuboki; M Murata
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 162, 190-195, May 2005, Incremental in-plane bending that has been invented by authors is a new and flexible manufacturing technology for small-lot production of strip with various bending radii. The strip is bent incrementally by an inclined punch beating. The prototype incremental bending machine uses the numerical control technology and bends the strip flexibly. The strip material is an important condition for in-plane bending. The bending experiments are carried out and some experimental results such as beating force, bending radius, strain distribution are experimentally examined. The forming properties of in-plane bending are clarified in this study. Moreover, the approximate formulas for calculation the bending radius are proposed. The bending radius calculated by the proposed formula agrees with one of the experiments. (c) 2005 Elsevier B.V. All rights reserved.
Scientific journal, English

Compression spinning of circular magnesium tube using heated roller tool
M Murata; T Kuboki; T Murai
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER SCIENCE SA, 162, 540-545, May 2005, Peer-reviwed, The tube has high bending and torsional rigidity considering its weight. Thus, tubular products are effective industrial parts to reduce their weight and their employments volume is increasing. Spinning is a very effective and flexible manufacturing technology for short production runs in a variety of sizes and shapes. Spinning is widely applied to the tube forming corresponding to the increasing usage of the tubular parts. Magnesium and its alloys have many good properties as strength to weight ratio, vibration absorbability and excellent recyclability. It is very difficult to form the magnesium alloy to various shaped products. But, it is easy to form the alloys at high temperature. Therefore, authors have invented new Computer Numerical Control (CNC) spinning machine, which has roller tools with heaters. The heated tools heat and form the magnesium tubes into various shapes by the spinning. The forming possibility of magnesium tube and the properties of formed tube are made clear in this paper. (c) 2005 Elsevier B.V. All rights reserved.
Scientific journal, English

Changing Inside Diameter of Circular Tube Using New Extrusion Method
M.Murata; T.Kuboki; T.Makiyama
Advanced Manufacturing Systems,Proceeding of The 8th India-Japan Joint Seminar, 15-20, Feb. 2005, Peer-reviwed
International conference proceedings, English

Design method of die geometry and pass schedule by void index in multi-pass drawing
T Kuboki; M Abe; Y Neishi; M Akiyama
JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME, ASME, 127, 1, 173-181, Feb. 2005, Peer-reviwed, The concept for die-geometry design is shown to suppress void growth in multi-pass drawing. First, the void index to evaluate the void fraction in multi-pass drawing was newly proposed based on the well-known equation to predict the fracture limit in cold working. Using finite element analysis, the influence of die geometries on the void index was investigated and it was clarified that the extra-low-angle die is effective whatever reduction in area is adopted. Moreover dies were designed to have the effect of suppressing void with the minimum die length. A series of experiments was then carried out that successfully verified the numerical results.
Scientific journal, English

2226 Compression of Magnesium Tube Using Spinning
Murata Makoto; Kuboki Takashi
The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2005, 615-616, 2005, Magnesium and its alloys are lightest metal in the many actual metal materials. They are taken notice of the material as the structural metal for energy saving. It is very difficult to form the magnesium alloy. But, it is easy to form the alloys over the recrystallization temperature. The many magnesium products are manufactured by casting and are not manufactured by metal forming. The tube has high bending and torsional rigidity as compared with its weight Tubular products are effective industrial parts to reduce their weight. The spinning can form the tubes to various shapes and is an effective metal forming. Authors have invented new CNC spinning machine which has roller tools with heaters. The forming limits, mechanical properties and accuracy are examined.
Japanese

2225 Nosing Process with Asymmetrical Conical Dies
KUBOKI Takashi; MURATA Makoto; KIMURA Yasuhiko
The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2005, 613-614, 2005, In this paper, new die which improves the process limited is proposed for nosing process of the circular tube. The usual dies are the symmetrical axis and cone. The asymmetrical conical dies which possess the relief in circumferential direction were devised. It did experiment of 3 sorts. As the first method, it did the press forming by the usual die. As the second method, while turning the circular tube to the usual die, it did press forming. As the last method, while turning the circular tube, it did the press forming by the new die. As a result, the load was reduced with the die which this paper proposed, and it was confirmed that a processing limit was improved.
Japanese

2228 Shear Bending Process of Circular Tubes
グダラズィ モハマド; 久保木 孝; 村田 眞
The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2005, 619-620, 2005, In order to minimize the space of bent tubular parts, a bending technology with small bending radii is requested. Tube shear bending is a suitable technology to realize a considerable small bending radius, which is very difficult to be manufactured with common cold-bending methods. It can be applied as an effective means when space limitation is a main design factor. Utilizing the shear bending process, production of compact and unified elbow tubular parts is feasible. In this paper, the procedure of tube shear bending has been introduced. Also, an elasto-plastic 3D simulation analysis for shear bending process of circular tubes was undertaken. As the result, the deformation behavior of tube as well as the effect of pushing force have been clarified.
Japanese

2238 Two roll straightening process of line materials
KUBOKI Takashi; MURATA Makoto; SASAKI Tetsuya
The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2005, 639-640, 2005, The straightening is a process of the final step of the steel bar and the wire rod. This paper describes, more popular straightening process, 2roll-straightening technique, and its experimental results. Geometrical and static analysis of concave and a convex roll were done by using three dimensions FEM. The result was that the change in 2-roll angles were equal to amount of bend under straightening process. We produced the straightening experiment machine from the result. And the optimum angle between the roll and roll pressure for 2-roll straightening process was clarified in this paper.
Japanese

2237 Method of controlling residual stress in drawing process of tube
SAKAKI Tomohiro; KUBOKI Takashi; MURATA Makoto
The proceedings of the JSME annual meeting, The Japan Society of Mechanical Engineers, 2005, 637-638, 2005, This paper describes two methods of controlling residual stress in drawing process. The methods are residual stress controls by (1) "skin-pass" and (2) core-bar drawing that puts mandrel internally in tube. Finite element analyses are conducted in order to investigate the effect of reduction of area and tool geometries on the residual stresses. It is numerically clarified that the "skin-pass" is effective to suppress the residual stress for thick-wall tubes. On the other hand, "core-bar drawing" is effective for thin-wall tubes. These analytical results are verified by the experiments.
Japanese

Suppression of Bending after Steel Bar Drawing by Heavy-Reduction Pass
Takashi Kuboki; Haruhiro Furuta; Masayoshi Akiyama
IMechE Journal of Engineering Manufacture, 216, 12, 1461-1470, Dec. 2004
Scientific journal, English

Numerical re-examination of the micro-scale mechanism of the Bauschinger effect in carbon steels
K Terada; K Matsui; M Akiyama; T Kuboki
COMPUTATIONAL MATERIALS SCIENCE, ELSEVIER SCIENCE BV, 31, 1-2, 67-83, Sep. 2004, Peer-reviwed, The micro-scale mechanism of the Bauschinger effect in carbon steels is re-examined by the numerical analyses on the periodic microstructures (unit cells) with elaborate illustrations and with our vocabulary in continuum mechanics. With the help of mathematical homogenization theory, we apply the finite element method to evaluate the mechanical behavior of unit cells, which are modeled as two-phase composites of ferrite and cementite, and simulate the uniaxial tension/compression tests for (medium) carbon steel. It is confirmed that the macroscopic responses obtained by the numerical simulations are qualitatively consistent with the experimental ones and that the extent of the Bauschinger effect is found to be sensitive to both the micro-scale morphology and the volume fraction of cementite. Then, by using illustrations of the transient states of stress and plastic strain in the unit cells, we search for the reasonable explanation for the micro-scale mechanism of the strain hardening from the initial yielding and the Bauschinger effect in the first macroscopic reverse loading. (C) 2004 Elsevier B.V. All rights reserved.
Scientific journal, English

テーパマンドレルを用いた変肉厚押出し加工におけるテーパ角の影響
牧山高大; 村田眞; 久保木孝
塑性と加工, 45, 524, 737-741, Sep. 2004, Peer-reviwed
Scientific journal, Japanese

平板の面内逐次打点曲げにおける押込み量の影響
金英俊; 久保木孝; 村田眞
軽金属, 54, 7, 287-292, Jul. 2004, Peer-reviwed
Scientific journal, Japanese

Die-less Bending Method for Precision U-bent Tube and Optimization of the Bending Conditions
Takashi Kuboki; Munekatsu Furugen; Shin-ichiro Osaka; Toshihide Ono
Proceedings of the 7th Japan-India Joint Seminar, 77-85, Feb. 2004
International conference proceedings, English

Development of Prototype CNC Extrusion Machine For Changing Wall Thickness of Tube with Tapered mandrel
Takahiro Makiyama; Takashi Kuboki; Makoto Murata
Asia Youth Forum on Advanced Manufacturing, AYFAM-paper(6), Feb. 2004
International conference proceedings, English

Effect of indentation in in-plane bending of sheet metal by incremental beating
Yingjun Jin; Takashi Kuboki; Makoto Murata
Keikinzoku/Journal of Japan Institute of Light Metals, Japan Institute of Light Metals, 54, 7, 287-292, 2004, Peer-reviwed, Incremental in-plane bending which has been invented by authors is a new and flexible manufacturing technology for small-lot, production of sheet metal with various bending radii. The sheet metal is bent incrementally by an inclined-punch beating. The prototype incremental bending machine uses the numerical control technology and bends the sheet metal flexibly. The bending experiments are carried out and some experimental results such as beating force, bending radius, strain distribution are experimentally examined. The forming properties of in-plane bending are clarified in this study. Moreover, approximate formulas for calculating the bending radius are proposed base on the plane strain. The bending radius calculated by the proposed formula agrees with the one of the experiments.
Scientific journal, Japanese

Comparison of Tubes with Variable Wall Thickness Produced by New Extrusion Method and Conventional Drawing Method
Takashi Kuboki; Takahiro Makiyama; Makoto Murata
Asia Pacific Tube 2003 in Thailand, 125-135, Sep. 2003
International conference proceedings, English

New Extrusion Process for Variable Wall Thickness Tubes
Takahiro Makiyama; Takashi Kuboki; Makoto Murata
Third International Conference and Exhibition on Design and Production of Dies and Molds, Bursa, Turkey, 177-180, Jun. 2003
International conference proceedings, English

Levelling Effect of Residual Stress by an Ultra-light Reduction at the Final Stage of Bar Drawing Process
Takashi Kuboki; Masayoshi Akiyama; Yutaka Neishi; Kouichi Kuroda
Asia Youth Forum on Advanced Manufacturing in Japan, 1-8, Mar. 2003
International conference proceedings, English

Method for Suppressing the Surface Cracking in Cold Forging
Satoru Watanabe; Yoshifumi Haruhata; Takashi Kuboki; Yutaka Neishi
Wire Journal International, 36, 1, 68-76, Jan. 2003, Peer-reviwed
Scientific journal, English

Influence of carbon content and carbide morphology of carbon steels on the stress-strain curve in the vicinity of yield point
Masayoshi Akiyama; Takashi Kuboki; Kenji Oikawa; Kazumi Matsui; Kenjiro Terada
J. of Materials Science and Technology (IOM), 18, 11, 1272-1278, Dec. 2002, Peer-reviwed
Scientific journal, English

マルチスケールモデリングによるBauschinger効果の発現メカニズムの解明
松井和己; 寺田賢二郎; 秋山雅義; 久保木孝; 及川兼司
日本機械学会, 68, 675, 71-78, Nov. 2002, Peer-reviwed
Scientific journal, Japanese

Influence of Carbon Content and Carbide Morphology on the Stress-Strain Curve and Bauschinger Effect
Takashi Kuboki; Masayoshi Akiyama; Kazumi Matsui; Kenjiro Terada
7th International Conference on Technology for Plasticity, 1201-1206, Oct. 2002
International conference proceedings, English

Reduction in Residual Stress After Cold Bar Drawing
Masayoshi Akiyama; Takashi Kuboki
7th International Conference on Technology for Plasticity, 361-366, Oct. 2002
International conference proceedings, English

Criterion of Crack Initiation in Cold Forging of Steels
Yutaka Neishi; Satoru Watanabe; Yoshifumi Haruhata; Takashi Kuboki; Kouichi Kuroda
7th International Conference on Technology for Plasticity, 715-720, Oct. 2002
International conference proceedings, English

炭素鋼の微視構造が巨視的な降伏･加工硬化特性に与える影響
松井和己; 寺田賢二郎; 秋山雅義; 久保木孝; 日下桂一; 及川兼司
土木学会 応用力学論文集, 土木学会, 5, 8, 175-183, Aug. 2002, Peer-reviwed
Scientific journal, Japanese

Satoru Watanabe, Yoshifumi Haruhata, Takashi Kuboki, Yutaka Neishi
Satoru Watanabe; Yoshifumi Haruhata; Takashi Kuboki; Yutaka Neishi
Conference Proceedings Wire and Technical Symposium 72nd Annual Convention, 59-69, Jun. 2002
International conference proceedings, English

冷間据込み時の割れ発生に及ぼす予ひずみの影響
根石豊; 渡部了; 春畑美文; 久保木孝; 黒田浩一
塑性と加工, 43, 496, 401-405, May 2002, Peer-reviwed
Scientific journal, Japanese

A Criterion to Predict the Surface Cracking in Cold Forging
Satoru Watanabe; Yoshifumi Haruhata; Yutaka Neishi; Takashi Kuboki
EAISI 2002 Japan Conference and Exhibition, 1, Paper 2, Apr. 2002
International conference proceedings, English

冷間据込み時の割れ発生予測
根石豊; 渡部了; 春畑美文; 久保木孝; 黒田浩一
塑性と加工, 日本塑性加工学会, 43, 439, 140-144, Feb. 2002, Peer-reviwed
Scientific journal, Japanese

Influences of Microstructural Morphology in Carbon Steels on the Initial Yielding Behaviour and the Bauschinger's Effect
AKIYAMA Masayoshi; KUBOKI Takashi; NEISHI Yutaka; MATSUI Kazumi; TERADA Kenjiro
Proceedings of the 1992 Annual Meeting of JSME/MMD, The Japan Society of Mechanical Engineers, 2002, 127-128, 2002, Calculated results by the homogenization methods were compared with the observed results by TEM to validate that morphology of carbide in the microstructure affects the mechanical properties of high carbon steel in the vicinity of initial yield point. The material was 0.80Cmass% carbon steel, and behaviours of two steels prepared by different thermal treatment were compared; (1) perfectly pearlitic structure, and (2) spheroidized carbide structure. It was also shown that similar mechanism occurring in the microstructure in the vicinity of initial yield point also applies to the mechanism dominating the Bauschinger's effect of these two steels.
Japanese

Optimisation of method for reducing residual stresses after cold bar drawing
M. Akiyama; T. Kuboki
Ironmaking and Steelmaking, IOM Communications Ltd., 29, 2, 101-106, 2002, Peer-reviwed, A new method to reduce the residual stresses after cold bar drawing has been proposed and optimised. This new method addresses the disadvantages of previous methods proposed by the authors, and needs neither the use of an extra finishing die nor an intricate die geometry. The application of axial tension to the bar or wire after drawing is all that is required, and by adjusting the magnitude of the tension it is possible to control the residual stresses in the final product. Axisymmetric elastic-plastic finite element analysis was carried out to examine quantitatively the influence of tension, followed by laboratory experiments using a thick, not thin, bar for convenience of measurement of residual stresses. The optimum value of tension was then determined. The applicability of the proposed method is discussed in the present paper. The new method is especially effective when applied to high speed cold drawing of an extremely thin wire, because the tension applied to the wire after finishing can be readily controlled simply by adjusting the peripheral speed of the rollers/pulleys. © 2002 IoM Communications Ltd.
Scientific journal, English

Die design by a void index in multi-pass drawing
T Kuboki; H Furuta; H Yoshikawa; Y Neishi; M Akiyama
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, PROFESSIONAL ENGINEERING PUBLISHING LTD, 216, 11, 1043-1049, 2002, Peer-reviwed, Die design was optimized for suppressing the void growth in multi-pass drawing. The void index to evaluate the void fraction in multi-pass drawing was first proposed, based on the well-known equation to predict the fracture limit in cold working. Using finite element analysis, the influence of die geometries on the void index was investigated and dies were designed to have the effect of suppressing void with the least minimum die length. A series of experiments was then carried out to verify the validity of the numerical analysis. The densities of drawn bars were measured and voids in microstructures were observed to verify the validity of the proposed void index.
Scientific journal, English

ダイレスＵベンド法の曲げ条件の最適化 －管材のダイレスＵベンド法の開発Ⅱ－
久保木孝; 古堅宗勝
塑性と加工, 42, 491, 1243-1247, Oct. 2001, Peer-reviwed
Scientific journal, Japanese

Influence of Mechanical Properties of Metallic Material on the Reducing Effect of Axial Residual Stress after Cold Drawing by a Double-taper Die
Takashi Kuboki; Yutaka Neishi; Kouichi Kuroda; Masayoshi Akiyama
J. of Japan Society of Technology for Plasticity, 日本塑性加工学会, 42, 486, 705-709, Jul. 2001, Peer-reviwed
Scientific journal, English

A study on the direct applicability of a set of grooves of multi-roll wire mills for different materials
K Kuroda; T Kuboki; M Akiyama; C Hayashi
JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME, ASME-AMER SOC MECHANICAL ENG, 123, 2, 272-278, May 2001, Peer-reviwed, Investigations were carried out on the direct applicability of a set of grooves of multi-roll wire mills for different materials having different stress-strain curves. Special evaluation was made on the stability of the geometry among different materials when rolled under the same mill setting conditions. Influence of inter-stand tension generated by the change in roll force due to the difference in stress-strain curve was studied both numerically and experimentally. A group of three-roll and four-roll-type mills is superior to two-roll-type mill in getting rid of the time for mill setting.
Scientific journal, English

Method for Suppressing Bending after Asymmetric Cutting of Cold-Drawn Bar
Satoru Watanabe; Masaaki Abe; Takashi Kuboki
Material Science Research International, 379-384, May 2001
International conference proceedings, English

A study on the influence of mechanical properties on the distribution of axial residual stress after cold drawing of metallic bars
T Kuboki; Kawakami, I; Y Neishi; K Kuroda; M AKiyama
MATERIALS SCIENCE RESEARCH INTERNATIONAL, SOC MATERIALS SCIENCE, JAPAN, 7, 1, 41-46, Mar. 2001, Peer-reviwed, Investigation was carried out on the influence of mechanical properties on the intensity of axial residual stress after cold drawing of metallic bars. Yield stress, Young's modulus, and work-hardening ratio were chosen as indications of mechanical properties, and quantitative influence was examined numerically on an ordinary cold drawing. After examining the quantitative influence of mechanical properties on the axial residual stress after drawing, further numerical experiments were carried out on the skin-pass effect in reducing the intensity of axial residual stress distribution, which the authors presented a result in the previous study by using S45C steel bars. In order to clarify the validity of the numerical analysis, various materials of different mechanical properties were selected, and cold drawing experiments were carried out in a laboratory to check the validity of the numerical results. The materials selected were (1) high-carbon steel, (2) medium carbon steel, (3) copper, and (4) aluminum. The residual stress was measured by Sachs method, and good agreement was obtained between the calculated and measured results in any case. It was found that the axial residual stress distribution is most sensitive to the work-hardening ratio, and an optimum skin-pass drawing condition was presented by quantitatively examining the effect of skin-pass in reducing the axial residual distribution.
Scientific journal, English

抽伸加工材の残留応力低減技術に関する研究
秋山雅義; 阿部正昭; 久保木孝
線材とその製品, 39, 3, 10-21, Mar. 2001, Peer-reviwed
Scientific journal, Japanese

534 A study on the macroscopic elastic-plastic mechanical behavior of steel affected by its micro-structure
MATSUI Kazumi; OIKAWA Kenji; TERADA Kenjiro; AKIYAMA Masayoshi; KUBOKI Takashi
Proceedings of the 1992 Annual Meeting of JSME/MMD, The Japan Society of Mechanical Engineers, 2001, 549-550, 2001
Japanese

Effect of die geometry on residual stress level present after bar drawing
T Kuboki; M Akiyama; Y Neishi; K Kuroda
IRONMAKING & STEELMAKING, I O M COMMUNICATIONS LTD INST MATERIALS, 28, 1, 65-71, 2001, Peer-reviwed, A new drawing die designed to reduce the residual stresses in bar after drawing is presented. The die design consists of two consecutive straight taper portions, and the outlet portion has a very small die angle. The marked beneficial effect of adding the outlet portion was predicted by finite element modelling (FEM), and subsequently verified by measuring the residual stresses in drawn bars. The optimum range of the outlet die angle was determined using FEM. The new design requires a slightly longer die length than the conventional one, but it is short enough to be adopted in current production lines.
Scientific journal, English

Influence of back-tension on effect of skin pass in minimising residual stress levels after cold rod drawing
T Kuboki; H Yoshikawa; Y Neishi; K Kuroda; M Akiyama
IRONMAKING & STEELMAKING, I O M COMMUNICATIONS LTD INST MATERIALS, 28, 2, 117-121, 2001, Peer-reviwed, Experimental and numerical investigations have been carried out on the influence of back-tension on residual stress levels after cold bar drawing. In particular, the influence on the skin pass effect was studied. Experimental and numerical results show that back-tension has little influence on the reduction of residual stress obtained following skin pass drawing. It is concluded that a skin pass can be incorporated into the final stage of drawing regardless of the draft schedule of the overall drawing process. (C) 2001 loM Communications Ltd.
Scientific journal, English

Design evaluation of multiroll mills for small-diameter wire rolling
K Kuroda; T Kuboki; Y Imamura; C Hayashi
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, PROFESSIONAL ENGINEERING PUBLISHING LTD, 215, 1, 77-86, 2001, Peer-reviwed, A comprehensive study on the evaluation of mill designs was carried out for three types of multiroll mill for wire rolling by using both prototype mills and numerical experiments. The laboratory experiments were carried out in order to examine both the deformation and loading characteristics of two-, three- and four-roll mills using a set of rolls of the same diameter. As a result, the data allow a direct comparison of the rolling characteristics among the three types of mill, which is not found in previous work. The analytical results showed a good matching with the experimental results, and evaluation was then carried out on the three mills. It has been found that the four-roll mill ensures the highest reduction and the two-roll mill the lowest reduction under the restriction that certain dimensional precision of the rolled wire be maintained. This tendency becomes greater as wire diameter decreases and in practice it is recommended that a four-roll mill equipped with small-diameter rolls be used when rolling small-diameter wire. As regarding the loading characteristics, similar conclusions apply. Finally, domains were determined where four-roll mills show their marked superiority.
Scientific journal, English

引抜き材の非軸対称切削加工時の曲がり抑制に関する検討
渡部了; 阿部正昭; 久保木孝
塑性と加工, 日本塑性加工学会, 41, 476, 896-900, Sep. 2000, Peer-reviwed
Scientific journal, Japanese

単スタンド解析用剛塑性FEMをベースとしたタンデム圧延解析用アルゴリズムの開発
久保木孝; 黒田浩一; 古田治弘; 村上真司
J. of the Japan Society for Technology of Plasticity, 41, 474, 701-705, Jul. 2000, Peer-reviwed
Scientific journal, Japanese

Levelling Effect of Residual Stress by an Ultra Light Reduction at the Final Stage of Bar Drawing Process
Takashi Kuboki; Masayoshi Akiyama; Yutaka Neishi; Kouichi Kuroda
The 6th International Conference on Residual Stresses, 109-104, Jul. 2000
International conference proceedings, English

ダイレスＵベンド法の理論解析 －管材のダイレスＵベンド法の開発Ⅰ－
久保木孝; 古堅宗勝; 逢阪慎一郎; 小野秀敏
J. of the Japan Society for Technology of Plasticity, 日本塑性加工学会, 41, 473, 617-621, Jun. 2000, Peer-reviwed
Scientific journal, Japanese

細径線圧延における工具接触状態に及ぼすミル形式の影響
黒田浩一; 秋山雅義; 久保木孝; 林千博
塑性と加工, 日本塑性加工学会, 41, 472, 487-491, May 2000
Scientific journal, Japanese

Effect of final drawing with light reduction on the levelling of residual stress distribution in cold bar drawing
T Kuboki; M Akiyama; Y Neishi; K Kuroda
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE, PROFESSIONAL ENGINEERING PUBLISHING LTD, 214, 11, 1389-1400, 2000, Peer-reviwed, A method is proposed for producing a significant reduction in the magnitude of the residual stress generated after cold drawing of a bar. It consists basically of a skin pass at the final stage of drawing and has a good levelling effect on the residual stress distribution as long as the final reduction falls within a specific range. The method was first proposed as a result of elastic-plastic finite element analyses using the ELFEN code developed by Rockfield Software Limited at the University of Wales, Swansea. The validity of the proposed method was verified by measuring the residual stress using the Sachs method.
Scientific journal, English

Development of Die-less Bending Process for Precision U-bent Tube
Takashi Kuboki; Munekatsu Furugen; Shin-ichiro Osaka; Toshihide Ono
The 7th International Conference on Steel Rolling, 318-323, Nov. 1998
International conference proceedings, English

Development of wire-sawing technology for manufacturing compact heat sinks for VLSI packages
M Kojima; T Kuboki; M Tasaka; C Hayashi; T Aihara
INTERNATIONAL JOURNAL OF THE JAPAN SOCIETY FOR PRECISION ENGINEERING, JAPAN SOC PRECISION ENG, 32, 2, 90-97, Jun. 1998, Peer-reviwed, Wire-sawing technology was developed for precision metal working and it was applied to manufacture heat sinks of aluminum alloy having plate-fins or pin-fins with an extremely narrow fin pitch. One of most distinguished features of this wire-saw is one-directional wire driving at a constant high velocity of which the maximum value is 800m per minute and another one is a supplying method of abrasive slurry for highly efficient metal working. The compact heat sinks both of plate-fin type and pin-fin type with fin pitch of 0.70mm and thickness of 0.35mm were manufactured by the wire-saw, and their heat transfer and pressure loss characteristics under forced air-cooling were experimentally studied. The present heat sinks gave cooling performance per unit heat sink volume of two to three times as large as conventional heat sinks. Because of the excellent cooling performance, the compact heat sinks are applicable to air-cooling for VLSI packages with high heat-generation density.
Scientific journal, English

歯当たりによる歯車の伝達誤差の推定法
久保愛三; 久保木孝; 野中鉄也
The Japan Society of Mechanical Engineers, The Japan Society of Mechanical Engineers, 56, 529, 2503-2509, Sep. 1990, Peer-reviwed, The correlation between transmission error of gears and some factors which are usually considered to express characteristics of tooth contactt pattern, such as areal percentage and total length of simultaneous contact lines, is examined, but very poor correlation is found. A new method of estimating the transmission error from a tooth contact pattern is introduced. This is a method of supposing a triangular shape for composite error on actual contact line which results in the ridge figure of the composite error surface as a function of tooth contact pattern. The transmission error is derived as a function of this ridge figure. The results estimated by this method showed fairly good correlation with the actual transmission error, especially for low transmitting load. Based on this method, an index value for the magnitude of transmission error is also introduced.
Scientific journal, Japanese

Micro incremental forming of sheet metal/foil by tiltable punch
久保木 孝
10 Mar. 2016, From Tech Review ( The Amada Foundation ), 25, 61-66, Japanese, Invited, Introduction commerce magazine

Simulation Methods for Tube Drawing, Extrusion for Understanding for Finite Element Analysis of Plastic Working
Takashi KUBOKI
Lead, The Japan Society for Technology and Plasticity, Nov. 2014, Journal of the Japan Society for Technology of Plasticity, 55, 646, 989-994, 0038-1586, 1882-0166

Tube Forming
久保木 孝; 内海 能亜; 寺前 俊哉; 陣内 雄士
Lead, The Japan Society for Technology and Plasticity, 2014, Journal of the Japan Society for Technology of Plasticity, 55, 643, 689-692, Japanese, 0038-1586, 1882-0166

Tube Forming
Tube Forming; Committee
The Japan Society for Technology and Plasticity, 25 Aug. 2013, Journal of the Japan Society for Technology of Plasticity, 54, 631, 675-679, 0038-1586, 1882-0166

金属円管の冷間曲げ加工と数値解析の精度向上への展望
久保木孝; 高橋和仁
Sep. 2008, 塑性と加工, 49, 572, 872-877, Japanese, Introduction other

チューブフォーミング
久保木 孝
Aug. 2008, 塑性と加工, 49, 571, 720-724, Japanese, Introduction other

Spinning of Aluminum Tube Using Conical Die with Escape
MURATA Makoto; KUBOKI Takahasi; TAKAHASHI Kazuhito; OHDE Yusuke
10 Oct. 2007, 大会講演概要, 113, 173-174, Japanese, 10022565597, AN10268641

L bending of sheet metal
JIN Yingjun; KOYAMA Junichi; IMAI Kazunari; KUBOKI Takashi
10 Oct. 2007, 大会講演概要, 113, 171-172, Japanese, 10022565594, AN10268641

「TUBEHYDRO 2007」国際会議を中国塑性加工学会と共催
久保木 孝; 吉田 佳典
Sep. 2007, 塑性と加工, 48, 560, 816-818, Japanese, Peer-reviwed, Introduction other

Stretch Bending for Rectangular Tube
TAKAHASHI Kazuhito; KUBOKI Takashi; MURATA Makoto
11 Apr. 2007, 大会講演概要, 112, 101-102, Japanese, 10022564871, AN10268641

Conical Nosing of Tube using Non-Circular Tapered Die
OHDE Yusuke; MURATA Makoto; KUBOKI Takashi
11 Apr. 2007, 大会講演概要, 112, 103-104, Japanese, 10022564876, AN10268641

Incremental bending of shaped beams
金 英俊; 山田 拓央; 石上 圭介; 久保木 孝; 村田 眞
11 Apr. 2007, 大会講演概要, 112, 99-100, Japanese, 10022564868, AN10268641

Evaluation of Strain Distribution in Tube shear Bending Using Numerical Simulation
GOODARZI Mohammad; KUBOKI Takashi; MURATA Makoto
01 Nov. 2004, 大会講演概要, 107, 309-310, English, 10022562195, AN10268641

Effect of rolling direction on incremental in-plane bending of sheet metal
JIN Yingjun; KUBOKI Takashi; MURATA Makoto
01 Nov. 2004, 大会講演概要, 107, 307-308, Japanese, 10022562191, AN10268641

Characteristics of Circular Tube Bending by MOS Method
MURATA Makoto
01 Sep. 2004, 材料とプロセス : 日本鉄鋼協会講演論文集 = Current advances in materials and processes : report of the ISIJ meeting, 17, 5, 1052-1052, Japanese, 0914-6628, 10013506828, AN10056461

Compression Spinning of Magnesium Tube
MURATA Makoto; KUBOKI Takashi
18 May 2004, 大会講演概要, 106, 163-164, Japanese, 10022561367, AN10268641

Compression spinning of square tube
ARO Hitomi; KUBOKI Takashi; MURATA Makoto
18 May 2004, 大会講演概要, 106, 285-286, Japanese, 10022561562, AN10268641

Effect of punch angle on incremental in-plane bending of sheet metal
JIN Y.; KUBOKI T.; MURATA M.
18 May 2004, 大会講演概要, 106, 279-280, Japanese, 10022561551, AN10268641

110 The influence of microstructure for the macroscopic elastic-plastic behavior of steel
MATSUI Kazumi; OIKAWA Kenji; TERADA Kenjiro; AKIYAMA Masayoshi; KUBOKI Takashi
The Japan Society of Mechanical Engineers, 27 Nov. 2001, The Computational Mechanics Conference, 2001, 14, 19-20, Japanese, 1348-026X, 110002486161, AA1190257X

A study on the macroscopic elastic-plastic material behavior of steel induced by its microstructures
OIKAWA Kenji; MATSUI Kazumi; TERADA Kenjiro; AKIYAMA Masayosi; KUBOKI Takashi
30 May 2001, 計算工学講演会論文集, 6, 2, 453-454, Japanese, 1342-145X, 10015778979, AN10581224

チューブフォーミング - 軽量化と高機能化の管材二次加工 -
栗山 幸久; 水越 秀雄; 内海 能亜; 加藤 和明; 奥出 裕亮; 長谷川 収; 水村 正昭; 淵澤 定克; 福村 卓巳; 白寄 篤; 久保木 孝; 陣内 雄士; 北澤 君義; 寺前 俊哉; 山内 浩行; 山藤 博文; 村上 碩哉; 吉原 正一郎; 古島 剛
Scholarly book, Japanese, Joint work, 第５章 管端加工, コロナ社, 22 Jul. 2019

引抜き -棒線から管までのすべて-
浅川基男; 齋藤賢一; 吉田一也; 相沢 隆; 上井 清史; 岩本 隆; 増田智一; 三村正直; 奥井達也; 高杉直樹; 土屋昭則; 久保木 孝; 中野 元裕; 梶川翔平
Scholarly book, Japanese, Joint work, 10.1, 10.3～10.8節(主執筆), コロナ社, 26 May 2017

60 Excellent Inventions in Metal Forming
著者数十人の一人
Scholarly book, English, Joint work, pp. 363-368, Springer, 01 Jun. 2015

Metal forming
Uday S. Dixit; R. Ganesh Narayana; Arbin; Kumar Singh; R. K; Uyyuru Shinjith; Satish V. Kailas; Santosh Kumar; Jay S. Gunaksekara; Arjann Buijk; Gary Huang; Gabriel Barton; Takashi Kuboki; P.P. Date; Ravindra K. Saxena; Prakash M. Dixit; K. Nrashimhan; Vinayak R. Malik; Sumitesh Das
English, Joint work, Chapter 7 Development of New Metal Forming Technologies Utilizing Computational and Experimental Approaches, McGraw Hill Education (India) Private Limited, Jun. 2013

COMPUTATIONAL METHODS FOR PLASTICITY: THEORY AND APPLICATION
寺田賢二郎; 渡邉育夢; 秋山雅義; 浅井光輝; 石井建樹; 生出佳; 岡澤重信; 久保木孝; 車谷麻緒; 斉木功; 高木知弘; 堤成一郎; 松井和己; 山川優樹
Japanese, Joint translation, 第6章(主担当) 数理塑性理論 第11章(副) 粘塑性 付録A(副) 対称テンソルの等方関数 付録B(副) テンソル指数関数, 森北出版, 2012

Effect of plug corner radius on forming accuracy in tube expansion drawing process
Shohei Kajikawa; Yusuke Kato; Shiliang Zhang; Takashi Kuboki
Oral presentation, English, The Proceedings of the 74th Japanese Joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, Toyama, Japan, Domestic conference
18 Nov. 2024

Application of material-properties prediction method based on area reduction in drawing to spinner-straightening analysis
Tetsuya Komatsu; Shohei Kajikawa; Shinsuke Inoue; Hiromichi Matsumura; Hikaru Seimiya; Takashi Kubok
Oral presentation, English, The Proceedings of the 74th Japanese Joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, Toyama, Japan, Domestic conference
18 Nov. 2024

Fabrication of Containers by Forging with High-Density Wood
Hinako Uejima; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, The Proceedings of the 74th Japanese Joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, Toyama, Japan, Domestic conference
17 Nov. 2024

Influence of Corner Radius of Plug on Dimensional Accuracy in Expansion Drawing
Shiliang Zhang; Takashi Kuboki; Masayoshi Akiyama; Shohei Kajikawa
Oral presentation, Japanese, The Proceedings of the 74th Japanese Joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, Toyama, Japan, Domestic conference
17 Nov. 2024

Two-step Press Forming Using Stepped Punch for Producing Deep Aluminum Cup with Flange
Yutaro Umehara; Takashi Kuboki; Takahi Iizuka; Shohei Kajikawa
Oral presentation, Japanese, The Proceedings of the 74th Japanese Joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, Toyama, Japan, Domestic conference
17 Nov. 2024

Enhancement of Formability in Cold Tube Forming by Unique Tool Shapes and Structures
Takashi Kuboki
Keynote oral presentation, English, 2023 Fall Conference of the Korean Society for Technology of Plasticity and materials processing, Invited
09 Nov. 2023

Virtual Compression Test by Multi-Scale Approach with Wood Cell Model
Shohei Kajikawa; Shota Oda; Takashi Kuboki; Masahiro Kondo; Mitsuru Abe; Masako Seki; Tsunehisa Miki; Eduardo de; Souza Neto
Oral presentation, COMPLAS XVII
06 Sep. 2023
05 Sep. 2023- 07 Sep. 2023

Application of Material-properties Prediction Method Based on Area Reduction in Drawing to Spinner-straightening Analysis
Tetsuya Komatsu; Shohei Kajikawa; Shinsuke Inoue; Hiromichi Matsumura; Hikaru Seimiya; Takashi Kuboki
COMPLAS XVII
06 Sep. 2023
05 Sep. 2023- 07 Sep. 2023

Sheet-Metal Bending Behaviour Considering Strain Rate and Bauschinger Effect in Finite Element Analysis
Tsuyoshi Muraoka; Yusuke Okude; Shohei Kajikawa; Takashi Kuboki
Oral presentation, English, COMPLAS XVII
05 Sep. 2023
05 Sep. 2023- 07 Sep. 2023

Analytical Study on Effect of Taper Angle And Roller Diameter on Twist Shape in Twist Rolling
Takashi Kuboki; Takahiro Makiyama; Avanish Kumar; Shohei Kajikawa
Oral presentation, English, COMPLAS XVII
05 Sep. 2023
05 Sep. 2023- 07 Sep. 2023

有限要素解析による木材の圧縮変形シミュレーション
織田 啓太郎; 久保木 孝; 田中 聡一; 三木 恒久; 梶川 翔平
Japanese, 2023年度塑性加工春季講演会講演論文集
11 Jun. 2023

ダイレスフレキシブルロール曲げにおける移動経路が曲げ挙動に及ぼす影響
薄井 陸; 梶川 翔平; 高橋 和仁; 梁田 陸; 久保木 孝
Japanese, 2023年度塑性加工春季講演会講演論文集
10 Jun. 2023

ボールスピンフォーミングを用いた拡管におけるプラグ半角および送りピッチが成形性に及ぼす影響
大栗 宗馬; 梶川 翔平; 久保木 孝
Japanese, 2023年度塑性加工春季講演会講演論文集
10 Jun. 2023

拡管型抽伸加工による四角管成形においてプラグ形状が成形性に及ぼす影響
加藤 優亮; 張 世良; 久保木 孝; 秋山雅義; 梶川 翔平
Japanese, 2023年度塑性加工春季講演会講演論文集
10 Jun. 2023

逃げ有りパンチを用いた回転口広げ加工においてパンチ接触面数が成形性に及ぼす影響
内田 究; 久保木 孝; 梶川 翔平
Japanese, 2023年度塑性加工春季講演会講演論文集
10 Jun. 2023

Reproduction of Compression Properties of Conifer by Multiscale Finite Element Analysis with Cell Structure Model
Shota Oda; Takashi Kuboki; Mitsuru Abe; Masahiro Kondo; Masako Seki; Tsunehisa Miki; Shohei Kajikawa
Oral presentation, Japanese, The 73rd Annual Meeting of Japan Wood Research Society
14 Mar. 2023

Effect of heating condition on flowability and physical properties of the flowed sample of cedar powder mixed with sucrose and citric acid
Megumi Goto; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, The 73rd Annual Meeting of Japan Wood Research Society
14 Mar. 2023

Effect of contact angle on deformation behavior in rotary tube flaring with relieved punch
Shohei Kajikawa; Kazumasa Iizuka; Kiwamu Uchida; Takashi Kuboki
Oral presentation, Japanese, The Proc. of the 73th Japanese Joint Conference for the Technology of Plasticity
18 Nov. 2022

Effect of Steel Ball Travel Path and Travel Speed on Parallel Shrunken Section in Flexible Ball Spin Forming
Taizan Kaneko; Shota Hirama; Shiori Gondo; Shohei Kajikawa; Takashi Kuboki
Oral presentation, The Proc. of the 73th Japanese Joint Conference for the Technology of Plasticity
18 Nov. 2022

Influence of parent tube material on deformation characteristics in the expansion drawing process
Shiliang Zhang; Takashi Kuboki; Masayoshi Akiyama; Shohei Kajikawa
Oral presentation, The Proc. of the 73th Japanese Joint Conference for the Technology of Plasticity
18 Nov. 2022

FEM study on Effect of Drawing Direction, Die Half Angle and Surface Ratio on Straightness after Drawing
Sho Matsumoto; Shohei Kajikawa; Takashi Kuboki
Oral presentation, The Proc. of the 73th Japanese Joint Conference for the Technology of Plasticity
18 Nov. 2022

Tool shapes and structures for stress control to achieve high formability and precise forming
Takashi Kuboki
Keynote oral presentation, English, Metal forming 2022, Invited, International conference
12 Sep. 2022

Human intuition versus numerical method on shape optimization for elongating life of V-bending die
Takashi Kuboki; Shohei Kajikawa; Kazuhito Takahashi
Oral presentation, English, CIRP, General Assembly, STC-F Technical presentation, CIRP, Bilbao, Spain (hybrid), International conference
26 Aug. 2022

Optimization of the force at tube bottom end in fabrication of a ring groove on tube inner-surface by ironing from outer surface
Junki Ishino; Shohei Kajikawa; Takashi Kuboki
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

Forming of Different Diameter Tubes by Controlling Steel Ball Position in Flexible Ball Spin Forming
Shota Hirama; Shiori Gondo; Shohei Kajikawa; Takashi Kuboki
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

Feasible Study of Dieless Flexible Roll Bending on Forming Limit by Finite Element Analysis
Riku Usui; Shohei Kajikawa; Kazuhito Takahashi; Riku Yanada; Takashi Kuboki
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

Effect of punch shape on formability in wood forging
Hinako Uejima; Shohei Kajikawa; Takashi Kuboki
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

Die-shape optimization for crack prevention and die-life longevity
Ryunosuke Yakuno; Takashi Kuboki; Shohei Kajikawa; Kazuhito Takahashi
Oral presentation
04 Jun. 2022

Influences of mechanical properties of parent tube on formability in tube expansion drawing
Shiliang Zhang; Shohei Kajikawa; Takashi Kuboki; Masayoshi Akiyama
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

Optimization of working condition in spinner straightening depending on wire-rod diameter and drawing reduction
Tetsuya Komatsu; shohei Kajikawa; Hiromichi Matsumura; Shinsuke Inoue; Hikaru Seimiya; Takashi Kuboki
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

Effect of bending-roll movement on bending limit and dimensional accuracy
Riku Yanada; Shohei Kajikawa; Kazuhito Takahashi; Riku Usui; Takashi Kuboki
Oral presentation, The Proc. of the 2022 Japanese Spring Conference for the Technology of Plasticity
04 Jun. 2022

マルチスケール有限要素解析による木材の圧縮特性の再現
小田 翔太; 梶川 翔平; 久保木 孝; 阿部 充; 関雅子; 三木 恒久; Eduardo de; Souza Neto
Oral presentation, Japanese, 日本材料学会 第71期学術講演会, 日本材料学会, Domestic conference
29 May 2022

Densification of Products Injection Molded from Wood Powder Combined with Sucrose and Citric Acid by Optimization of Particle Size
Shohei Kajikawa; Kiu Cho; Takashi Kuboki
Poster presentation, Japanese, The 72nd Annual Meeting of Japan Wood Research Society, Domestic conference
15 Mar. 2022

拡管型抽伸加工におけるプラグ半角が成形性に及ぼす影響
張 世良; 川口 光; 梶川 翔平; 久保木 孝; 赤坂 勇; 寺下 雄三; 秋山 雅義
Oral presentation, Japanese, 第72回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
30 Oct. 2021

拡管型抽伸加工による角形管成形における工具形状の検討
梶川 翔平; 張 世良; 久保木 孝; 赤坂 勇; 寺下 雄三; 秋山 雅義
Oral presentation, Japanese, 第72回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
30 Oct. 2021

逃げ有りプラグを用いた回転口広げ加工 -管の成形性に及ぼすプラグ送り量の影響-
飯塚 和正; 久保木 孝; 梶川 翔平
Oral presentation, Japanese, 第72回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
30 Oct. 2021

フレキシブルボールスピンフォーミングにおける鋼球径および押込み速度の影響
平間 章太; 池田 峻之; 権藤 詩織; 梶川 翔平; 久保木 孝
Oral presentation, Japanese, 第72回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
30 Oct. 2021

外面しごき凹部転写成形における管下端部への軸方向力制御の適用
石野 淳貴; 梶川 翔平; 久保木 孝
Oral presentation, Japanese, 第72回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
30 Oct. 2021

冷却ダイを用いた天然系バインダ混合木粉の押出し加工による円管成形
鈴本 雄也; 久保木 孝; 梶川 翔平
Oral presentation, Japanese, 第72回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
29 Oct. 2021

Tube forming and fabricating technologies for contributing society by tackling problems of Environment and Aging Population
Takashi Kuboki; Atsushi Shirayori; Masaaki Mizumura; Noah Utsumi; Yeong-Maw Hwang
Keynote oral presentation, English, Int. Conf. Techn. Plast. (ICTP2021), Invited, International conference
29 Jul. 2021

Development of Twisting Method for Sheet Metal using Taper Roll
Avanish Kumar; Shohei Kajikawa; Takashi Kuboki; Takahiro Makiyama
Oral presentation, Japanese, 2021年度塑性加工春季講演会講演論文集, 日本塑性加工学会, Domestic conference
04 Jun. 2021

Effect of blank shape on deep drawability for forming rectangular cases with high aspect ratio
Tomoya Takasan; Shohei Kajikawa; Takashi Kuboki; Kenji Tamaoki; Katsuyuki Onishi; Akira Gunji; Akira Yamauchi
Oral presentation, Japanese, 2021年度塑性加工春季講演会講演論文集, Domestic conference
04 Jun. 2021

スクロースおよびクエン酸を混合した木質系粉末の流動性に及ぼす加熱温度および時間の影響
後藤 めぐみ; 梶川 翔平; 久保木 孝
Oral presentation, Japanese, 第71回日本木材学会大会, 日本木材学会, Web講演会, Domestic conference
19 Mar. 2021

Attempt of tube production by wood powder combining natural binder
Yuya Suzumoto; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, 第71回塑性加工連合講演会講演論文集, 日本塑性加工学会, WEB講演会, Domestic conference
14 Nov. 2020

Rotary flaring with relieved plug - Effect of contact angle of relieved plug on forming limit and accuracy -
Kazumasa Iizuka; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, The Proc. of the 71th Japanese Joint Conference for theTechnology of Plasticity, 日本塑性加工学会, Domestic conference
14 Nov. 2020

Flexible diameter reduction on middle of tube by ball spin forming
Shota Hirama; Takayuki Ikeda; Shohei Kajikawa; Takashi Kuboki
Oral presentation, Japanese, The Proc. of the 71th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, WEB講演会, Domestic conference
14 Nov. 2020

Fabrication of a ring groove on inner surface of tube by ironing from outer surface using displacement control of tube bottom end
Junki Ishino; Shohei Kajikawa; Takashi Kuboki; Akira Yamauchi; Akira Gunji; Katsuyuki Onishi
Oral presentation, Japanese, The Proc. of the 71th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, WEB講演会, Domestic conference
14 Nov. 2020

Recent trends and perspectives in tube forming
Takashi Kuboki
Keynote oral presentation, English, TUBEHYDRO 2019, Taiwan Society for Technology of Plasticity, Kaohsiung, Taiwan, International conference
19 Nov. 2019

V曲げにおける加工空間の縮小を目的とした板材のアンバランス曲げ加工法
羽田野 貴宏; 久保木 孝; 梶川 翔平; 金 英俊; 小俣 均; 黄 河; 木村 圭太
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
13 Oct. 2019

銅管断面の肉厚および溝の有無が回転引き曲げ加工における不良現象に及ぼす影響
荒木 聖人; 久保木 孝; 梶川 翔平; 細木 哲郎; 崩岡 久敏; 土屋 昭規
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
13 Oct. 2019

天然系バインダを混合した木質系粉末の流動挙動および成形性 に及ぼす粒子サイズの影響
曺 基宇; 梶川 翔平; 久保木 孝
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
12 Oct. 2019

転造加工における内部割れ発生要因の検討
松村 和華; 梶川 翔平; 久保木 孝; 山根 康嗣
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
12 Oct. 2019

管型抽伸加工法の開発（第2報)－成形性に及ぼす拡管率の影響－
川口 光; 梶川 翔平; 久保木 孝; 赤坂 勇; 寺下 雄三; 秋山 雅義
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
12 Oct. 2019

スピンナー矯正加工の有限要素法解析
川崎 圭一郎; 久保木 孝; 梶川 翔平; 松村 弘道; 小野 哲士; 清宮 光
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
12 Oct. 2019

遊星ボールを用いたフレキシブルな縮径加工
池田 峻之; 久保木 孝; 梶川 翔平
Oral presentation, Japanese, 第70回塑性加工連合講演会講演論文集, 日本塑性加工学会, 習志野市, Domestic conference
12 Oct. 2019

スクロースおよびクエン酸を混合した木質系粉末の射出成形
梶川 翔平; 堀越 将矢; 久保木 孝
Oral presentation, Japanese, 2019年度塑性加工春季講演会講演論文集, Domestic conference
08 Jun. 2019

将来のチューブフォーミング技術
久保木 孝
Oral presentation, Japanese, チューブフォーミング分科会40周年・研究例会第150回記念行事, Domestic conference
11 Mar. 2019

T. Kuboki, Y. Jin: Light indentation method of sheet-metal edge for suppression of warp in U-shape bending of laser-cut sheets
Takashi Kuboki; Yingjun Jin
Oral presentation, English, CIRP, Winter meeting, STC-F technical presentation, International conference
22 Feb. 2019

1D bending process with shear bending
楠田 大介; 久保木 孝; 梶川 翔平; 森本 直之; 野口 敬広; 足立 一晃
Oral presentation, Japanese, 第69回塑性加工連合講演会, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

断面が均一な矩形のコイルばねの成形法の開発
松村 和華; 岡田 光平; 梶川 翔平; 久保木 孝
Oral presentation, Japanese, 第69回塑性加工連合講演会講演論文集, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

板金・板材のジグザク曲げ加工における凹凸とスプリングバックの抑制法の安定性
羽田野 貴宏; 久保木 孝; 梶川 翔平; 山田 拓馬; 阿部 浩行
Oral presentation, Japanese, 第69回塑性加工連合講演会講演論文集, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

内面螺旋溝付管の押出し加工において，管外面形状がリード角に及ぼす影響
原 陽一郎; 石川 道明; 梶川 翔平; 久保木 孝; 村田 眞
Oral presentation, Japanese, 第69回塑性加工連合講演会講演論文集, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

動的用解法によるスピンナー矯正加工の有限要素法解析
川崎 圭一郎; 楠田 大介; 久保木 孝; 梶川 翔平; 松村 弘道; 小野 哲士; 清宮 光
Oral presentation, Japanese, 第69回塑性加工連合講演会公演論文集, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

拡管型抽伸加工法の開発－円管材の限界口広げ率に関する検討－
川口光; 梶川翔平; 久保木孝; 赤坂勇; 寺下雄三; 池田正美; 秋山雅義
Oral presentation, Japanese, 第69回塑性加工連合講演会講演論文集, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

外面しごき加工による円筒内面への凹部転写成形における成形限界の検討
小沢 竜徳; 久保木 孝; 梶川 翔平; 山内 章; 郡司 章; 大西 堅幸
Oral presentation, Japanese, 第69回塑性加工連合講演会講演論文集, 日本塑性加工学会, 熊本市, Domestic conference
27 Oct. 2018

Effect of mandrel shape on defect phenomena in small-diameter-bending of thin copper tube
Masato Araki; Takashi Kuboki; Shohei Kajikawa; Akinori Tsuchiya; Hisatoshi Tsueoka; Masato Watanabe
Oral presentation, Japanese, The Proc. of the 2018 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, Tokyo, Domestic conference
02 Jun. 2018

Reduction of tube diameter by ball spin forming
Takayuki Ikeda; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, The Proc. of the 2018 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, 東京, Domestic conference
01 Jun. 2018

Effect of grain size on formability of wood forming with natural agents
Kiu Cho; Shohei Kajikawa; Takashi Kuboki
Oral presentation, Japanese, The Proc. of the 2018 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, 東京, Domestic conference
01 Jun. 2018

高圧水を用いた深絞り加工などにおける潤滑剤の流体挙動と塑性変形の準連成解析
久保木 孝
Public discourse, Japanese, 日本塑性加工学会プロセッシング計算力学分科会 第60回セミナー, Invited, 日本塑性加工学会プロセッシング計算力学分科会, Domestic conference
06 Apr. 2018

Incremental bending of sheet metal using a tiltable punch
Takashi Kuboki; Shohei Kajikawa; Yingjun Jin; Armad Azrie
Oral presentation, Japanese, 日本機械学会関東支部 第24期講演会, 日本機械学会関東支部, 東京都，調布市, Domestic conference
17 Mar. 2018

Effect of tool shape on formability in stretch forming of sheet metal applying compressive force
Shohei Kajikawa; Takashi Kuboki; Takashi Iizuka
Oral presentation, Japanese, 日本機械学会関東支部 第24期講演会, Domestic conference
17 Mar. 2018

Effect of particle size on moldability of wood powder combining natural additive
Cho Kiu; Masaya Horikoshi; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, 日本機械学会関東学生会第57回学生員卒業研究発表講演会, 日本機械学会関東支部, 東京都，調布市, Domestic conference
16 Mar. 2018

Effect of Tool Shape on Rotating Pull Bending of Thin Copper Tube
Masato Araki; Takashi Kuboki; Shohei Kajikawa; Akinori Tsuchiya; Hisatoshi Tsueoka; Masato Watanabe
Oral presentation, Japanese, 日本機械学会関東学生会第57回学生員卒業研究発表講演会, 日本機械学会関東支部, 東京都，調布市, Domestic conference
16 Mar. 2018

Reduction of tube diameter by planetary-ball spin forming
Takayuki Ikeda; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, 日本機械学会関東学生会第57回学生員卒業研究発表講演会, Domestic conference
16 Mar. 2018

Control of strain history for obtaining FLD in upset forming and dependency of FLD on hardness
T. Kuboki
Oral presentation, English, CIRP, Winter meeting, STC-F Technical presentation, International conference
22 Feb. 2018

内外面に螺旋溝を有する円管の押出し加工法
石川 道明; 久保木 孝; 梶川 翔平; 村田 眞
Oral presentation, Japanese, 第68回塑性加工連合講演会講演論文集, Domestic conference
10 Nov. 2017

加工空間の縮小を目的とした板材のアンバランス曲げ加工法
大場 渉; 久保木 孝; 梶川 翔平; 金 英俊; 黄 河
Oral presentation, Japanese, 第68回塑性加工連合講演会講演論文集, Domestic conference
10 Nov. 2017

ピルガ圧延においてマンドレル支持部の弾性変形が圧延挙動に及ぼす影響
村岡 剛; 久保木 孝; 梶川 翔平; 彌永 大作; 黒田 浩一
Oral presentation, Japanese, 第68回塑性加工連合講演会講演論文集, Domestic conference
10 Nov. 2017

Effect of Die Position on Straightness of Wire Rods in Spinner Straightener
Daisuke Kusuda; Takashi Kuboki; Shohei Kajikawa; Hiromichi Matsumura; Satoshi Ohno; Hikaru Seimiya
Oral presentation, English, The Proc. of the 68th Japanese Joint Conference for the Technology of Plasticity, Domestic conference
10 Nov. 2017

Fabrication of a Ring Groove on Inner Tube Surface by Ironing from Outer Surface
Tatsunori Ozawa; Takashi Kuboki; Shohei Kajikawa; Yamauchi Akira; Gunji Akira; Katsuyuki Onishi
Oral presentation, English, The Proc. of the 68th Japanese Joint Conference for the Technology of Plasticity, Domestic conference
10 Nov. 2017

Fabrication of a ring groove on inner tube surface by ironing from outer surface
Fabrication of; a; rin; roo; urface by ironing; from outer surface
Oral presentation, Japanese, The Proc. of the 2017 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, 岐阜, Domestic conference
09 Jun. 2017

Effect of die position on straightness of bar in spinner straightener
Daisuke Kusuda; Takashi Kuboki; Shohei Kajikawa; Hiromichi Matsumura; Tetsushi Ono; Hikaru Seimiya
Oral presentation, Japanese, The Proc. of the 2017 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, 岐阜, Domestic conference
09 Jun. 2017

スピンナー矯正加工において矯正工具の押込み量が線材の真直度に及ぼす影響
楠田 大介; 久保木 孝; 梶川 翔平; 松村 弘道; 小野 哲士; 清宮 光
Oral presentation, Japanese, 日本機械学会関東学生会第56回学生員卒業研究発表講演会, 日本機械学会関東学生会, 東京, Domestic conference
16 Mar. 2017

外面しごき加工による円筒内面への凹部転写成形
小沢 竜徳; 久保木 孝; 梶川 翔平; 山内 章; 郡司 章; 大西 堅幸
Oral presentation, Japanese, 日本機械学会関東学生会第56回学生員卒業研究発表講演会, 日本機械学会関東学生会, 東京, Domestic conference
16 Mar. 2017

An extrusion method of a tube with a pre-worked rib using a functional mandrel with guides
T. Kuboki; T. Moroi; Makoto Murata
Oral presentation, English, CIRP, Winter meeting, STC-F Technical presentation, International conference
16 Feb. 2017

Forming method of coiled spring with high rectangle ratio cross section and small diameter
Tsuyoshi Muraoka; Tsubouchi Tsubasa; Takashi Kuboki; Shohei kajikawa
Oral presentation, Japanese, The Proc. of the 67th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, Saitama, Domestic conference
23 Oct. 2016

Effect of Pressure Die Shapes on Formability of Thin-walled Copper Tube in Draw Bending with Small Diameter
Kieita Kimura; Takashi Kuboki; Shohei Kajikawa; Masato Watanabe; Hisatoshi Tsueoka
Oral presentation, Japanese, The Proc. of the 67th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, Domestic conference
23 Oct. 2016

Multi-stage forming process for reduction of tube tips by rotary dies with relief surfaces
Wataru Oba; Yusuke Imaizumi; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, The Proc. of the 67th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, Saitama, Domestic conference
21 Oct. 2016

Effect of shoulder shape of punch and die on formability of sheet metal in combining process of drawing and ironing by compressive force
Shohei Kajikawa; Takashi Kuboki; Takashi Iizuka
Oral presentation, Japanese, The Proc. of the 67th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, Domestic conference
21 Oct. 2016

Flexible forming processes from/to sheet metals
T. Kuboki; S. Kajikawa
Oral presentation, English, CIRP, General Assembly, STC-F Technical presentation, International conference
26 Aug. 2016

Development of a forming method of spring with high-rectangle-ratio cross section and small spring diameter
Takashi Kuboki; Shohei Kajikawa; Tsuyoshi Muraoka; Tsubasa Tsubouchi
Oral presentation, Japanese, The Proc. of 2016 Spring Lecture Meeting of Japan Society of Spring Engineers, Domestic conference
09 Jun. 2016

Effect of Tension and Crash on Reduction in Tube Diameter in Tube Drawing using A Pair of Concave Rolls
Shohei Kajikawa; Takashi Kuboki
Oral presentation, Japanese, The Proc. of the 2016 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, 京都, Domestic conference
22 May 2016

Proposal of a FEA model for shortening calculation time
Tsuyoshi Muraoka; Takashi Kuboki; Shohei Kajikawa; Shohei Kajikawa; Daisaku Yanaga; Koichi Kuroda
Oral presentation, Japanese, The Proc. of the 2016 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, Kyoto, Domestic conference
22 May 2016

The effect of mandrel and pressure die shapes in draw bending of thin-walled copper tube
Keita Kimura; Guanghui Wang; Takashi Kuboki; Shohei Kajikawa; Masato Watanabe; Yoshinori Tsuchiya
Oral presentation, Japanese, 平成28年度塑性加工春季講演会講演論文集, Domestic conference
21 May 2016

Effect of groove shape and angles of tools on formability in tube extrusion with spiral projections
Michiaki Ishikawa; Taro Yagita; Makoto Murata; Takashi Kuboki; Shohei Kajikawa
Oral presentation, Japanese, The Proc. of the 2016 Japanese Spring Conference for the Technology of Plasticity, 日本塑性加工学会, 京都, Domestic conference
21 May 2016

Die-less Flexible forming processes on tube
T. Kuboki; S. Kajikawa
Oral presentation, English, CIRP, Winter meeting, STC-F Technical presentation, International conference
18 Feb. 2016

Appropriate tool geometry for estimation of stress-strain based on punch load in stretch forming
Wataru Oba; YingJun Jin; Takashi Kuboki
Oral presentation, Japanese, The Proc. of the 66th Japanese Joint Conference for the Technology of Plasticity, 日本塑性加工学会, Iwaki, Domestic conference
31 Oct. 2015

Fabrication of coiled springs with high rectangular ratio in cross-section from hollow coil and its evaluation
Tsuyoshi Muraoka; Tsubasa Tsubouchi; Takashi Kuboki
Oral presentation, Japanese, The Proc. of the 66th Japanese Joint Conference for the Technology of Plasticity, Iwaki, Domestic conference
29 Oct. 2015

管抽伸加工において初期偏肉と肉厚圧下率が成形後の断面および長手方向寸法精度に及ぼす影響
田坂 俊祐; 久保木 孝; 黒田 浩一; 奥井 達也
Oral presentation, Japanese, 平成27年度塑性加工春季講演会講演論文集, 日本塑性加工学会, 横浜市, Domestic conference
31 May 2015

引抜き加工における潤滑剤挙動を対象とする有限要素法と数値流体力学の連成解析
久保木 孝; 堀越 祐樹
Oral presentation, Japanese, 平成27年度塑性加工春季講演会講演論文集, 日本塑性加工学会, 横浜市, Domestic conference
31 May 2015

薄肉銅管の回転引き曲げ加工においてマンドレル位置が断面形状としわ・割れに及ぼす影響
王 広輝; 久保木 孝; 渡辺 雅人; 土屋 昭則
Oral presentation, Japanese, 平成27年度塑性加工春季講演会講演論文集, 日本塑性加工学会, 横浜市, Domestic conference
30 May 2015

内面に突起を有する円管の押出し加工におけるベアリング内面溝数の影響
八木田 太郎; 久保木 孝; 村田 眞
Oral presentation, Japanese, 第65回塑性加工連合講演会講演論文集, 日本塑性加工学会, Domestic conference
13 Oct. 2014

Method of reducing redisual stress generated by thermal cutting of sheet metal attendat upon material property
Atsushi Maeda; Takashi Kuboki; Yingjun Jin
Oral presentation, English, The Proc. of the 64th Japanese joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, 岡山市, Domestic conference
12 Oct. 2014

The effect of ditch-engrabed die in deep drawing with high-pressured water jet
Yuki Horikoshi; Takashi. Kuboki; Makoto Murata; Kazumi Matsui; Makoto Tsubokura
Oral presentation, English, The Proc. of the 64th Japanese joint Conference for the Technology of Plasticity, The Japan Society for Technology of Plasticity, Okayama city, Domestic conference
12 Oct. 2014

Lubrication behavior of deep drawing with high pressured water
T. Kuboki
Oral presentation, English, CIRP, General Assembly, STC-F Technical presentation, International conference
29 Aug. 2014

巻線断面に高矩形比を持つコイルばねの成形および性能
坪内 翼; 久保木 孝
Oral presentation, Japanese, 平成26年度塑性加工春季講演会, 日本塑性加工学会, つくば市, Domestic conference
07 Jun. 2014

内面に突起を有する円管の押出し加工
村田 眞; 八木田 太郎; 久保木 孝
Oral presentation, Japanese, 平成26年度塑性加工春季講演会, 日本塑性加工学会, つくば市, Domestic conference
07 Jun. 2014

内面に突起を有する円管の押出し加工におけるベアリング長さの影響
八木田 太郎; 久保木 孝; 村田 眞
Oral presentation, Japanese, 平成26年度塑性加工春季講演会, 日本塑性加工学会, つくば市, Domestic conference
07 Jun. 2014

Introduction and perspectives of closed-loop control in precise sheet-metal bending
T. Kuboki; Y. Jin
Oral presentation, English, CIRP, Winter meeting, STC-F, Technical presentation, International conference
23 Jan. 2014

厚板のV曲げ加工において生じる不良現象
ハムタ ナランバータル; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 第64回塑性加工連合講演会, 日本塑性加工学会, 大阪, Domestic conference
01 Nov. 2013

せん断角度が複合材の切断面性状に及ぼす影響
佐藤 駿; 久保木 孝
Oral presentation, Japanese, 第64回塑性加工連合講演会, 日本塑性加工学会, 大阪, Domestic conference
01 Nov. 2013

Micro-Incremental In-Plane Bending Utilizing Small Punch Tool
Armad Azrie; Takashi Kuboki
Oral presentation, English, 第64回塑性加工連合講演会, 日本塑性加工学会, 大阪, Domestic conference
01 Nov. 2013

時効現象を考慮した棒線材の変形解析手法
久保木 孝
Oral presentation, Japanese, 日本塑性加工学会,平成25年度塑性加工春季講演会, 名古屋市
Jun. 2013

逃げ有りダイス口絞り加工におけるダイス半角条件の有限要素法解析による評価
阿部 光将; 久保木 孝
Oral presentation, Japanese, 日本塑性加工学会,平成25年度塑性加工春季講演会
Jun. 2013

高圧水深絞り加工法における水膜挙動のReynolds方程式による評価
堀越 祐樹; 久保木 孝; 村田 眞; 坪倉 誠; 松井 和己
Oral presentation, Japanese, 日本塑性加工学会,平成25年度塑性加工春季講演会
Jun. 2013

有限要素法を用いたV曲げ加工における曲げ角度の予測精度
KHAMT NARANBAATAR; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,平成25年度塑性加工春季講演会
Jun. 2013

厚板のV曲げ加工における精度向上
ハムタ ナランバータル; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,第63回塑性加工連合講演会, 北九州市
Nov. 2012

円管内壁に捩じられた突起を有する押出加工における捩じり角の影響
村田 眞; 久保木 孝; 山崎 弘之
Oral presentation, Japanese, 日本塑性加工学会,第63回塑性加工連合講演会
Nov. 2012

鋼管ロータリ矯正の３次元解析
黒田 浩一; 大田尾 修治; 奥井 達也; 久保木 孝; 黄 河
Oral presentation, Japanese, 日本塑性加工学会,第63回塑性加工連合講演会
Nov. 2012

鋼管ロータリ矯正におけるロールマーク発生メカニズムの検討
大田尾 修治; 黒田 浩一; 山川 富夫; 奥井 達也; 久保木 孝
Oral presentation, Japanese, 日本塑性加工学会,第63回塑性加工連合講演会
Nov. 2012

圧延された銅板の機械特性変化の予測
久保木 孝; 松本 亨; 金 英俊; 寺田 賢二郎
Oral presentation, Japanese, 日本塑性加工学会,第63回塑性加工連合講演会
Nov. 2012

せん断加工条件が複合材の切断面性状に及ぼす影響
佐藤 駿; 久保木 孝
Oral presentation, Japanese, 日本塑性加工学会,第63回塑性加工連合講演会
Nov. 2012

高圧水を用いた深絞り加工における潤滑特性の検討
斉藤 弘; 久保木 孝; 村田 眞; 坪倉 誠; 松井 和己
Oral presentation, Japanese, 日本塑性加工学会,平成24年度塑性加工春季講演会
Jun. 2012

電縫管の均等曲げにおける変形挙動
髙橋 和仁; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成24年度塑性加工春季講演会
Jun. 2012

逃げ有りダイスを用いた口絞り加工におけるダイス半角および接触角度の影響
阿部 光将; 久保木 孝
Oral presentation, Japanese, 日本塑性加工学会,平成24年度塑性加工春季講演会
Jun. 2012

マイクロ遂次打点曲げ加工におけるパンチ先端角度の影響
Ahmad Azrie; 久保木 孝
Oral presentation, Japanese, 日本塑性加工学会,平成24年度塑性加工春季講演会
Jun. 2012

厚板のＶ曲げ加工とＬ曲げ加工における変形形状の比較検討
ハムタ ナランバータル; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,平成24年度塑性加工春季講演会
Jun. 2012

押出し加工による内面壁に捻られた突起を付けた円管の突起数の影響
村田 眞; 稲川 雄貴; 久保木 孝; 山崎 弘之
Oral presentation, Japanese, 日本塑性加工学会,平成24年度塑性加工春季講演会
Jun. 2012

板材のせん断加工における切断特性の解析および実験的検討
路 大涛; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

鋼板のレーザ切断における加工変質層および残留応力特性
村上 祐一; 久保木 孝; 伊藤 敬; 金 英俊
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

ダイス曲げ半径に応じた側面圧縮ダイスにおける圧縮量の適正化
髙橋 和仁; 山口 康大; 久保木 孝; 村田 眞
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

内面にスパイラルの突起を持つ円管の押出加工
村田 眞; 小林 雅志; 稲川 雄貴; 久保木 孝
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

V曲げ加工における厚板の変形形状に及ぼす板幅の影響
ハムタ ナランバータル; 久保木 孝; 村田 眞; 金 英俊
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

Ｌ曲げ加工を用いた板材の高精度曲げ加工
村田 眞; ハムタ ナランバータル; 金 英俊; 久保木 孝
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

薄板のＬ曲げ加工における曲げ半径の影響
林 洪らん; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

銅板の機械特性に及ぼす圧延圧下率の影響
松本 亨; 久保木 孝; 金 英俊
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

極薄板の逐次打点曲げ加工
濱 智史; 久保木 孝
Oral presentation, Japanese, 第62回塑性加工連合講演会講演論文集/日本塑性加工学会,第62回塑性加工連合講演会
Oct. 2011

有限要素法を用いたマイクロチューブにおけるプラグ形状の選定
森脇 勇介; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演会講演論文集
Jun. 2011

側面圧縮を付与した回転引曲げ加工における5056アルミニウム合金円管のへん平抑制
高橋和仁; 平塚友望; 久保木孝; 村田眞; 矢野功造
Oral presentation, Japanese, 軽金属学会,軽金属学会第119回秋期大会講演概要
Nov. 2010

1050板の新しいせん断加工と従来のせん断加工との加工力の比較
路大涛; 村田眞; 久保木孝; 金英俊
Oral presentation, Japanese, 軽金属学会,軽金属学会第119回秋期大会講演概要
Nov. 2010

5083アルミニウム合金厚板の突き曲げに関する研究
ハムタ・ナランバータル; 村田眞; 久保木孝; 柴田隆造; 金英俊
Oral presentation, Japanese, 軽金属学会,軽金属学会第119回秋期大会講演概要
Nov. 2010

管の矯正加工における断面の変形挙動
黄 河; 久保木 孝; 村田 眞
Oral presentation, Japanese, 第61回塑性加工連合講演会講演論文集/日本塑性加工学会,第61回塑性加工連合講演会/日本塑性加工学会
Oct. 2010

凹型ロールを用いた伸線加工における被加工材の機械的特性
青木 一充; 久保木 孝; 村田 眞
Oral presentation, Japanese, 第61回塑性加工連合講演会講演論文集/日本塑性加工学会,第61回塑性加工連合講演会
Oct. 2010

穴のあいたリブを有する管の押出し接合における材料流動
諸井 努; 久保木 孝; 村田 眞
Oral presentation, Japanese, 第61回塑性加工連合講演会講演論文集/日本塑性加工学会,第61回塑性加工連合講演会
Oct. 2010

バウシンガー効果を考慮した板曲げスプリングバック予測に関する研究
後藤 慎太郎; 久保木 孝; 村田 眞; 金 英俊
Oral presentation, Japanese, 第61回塑性加工連合講演会講演論文集/日本塑性加工学会,第61回塑性加工連合講演会
Oct. 2010

極薄肉大径長尺管成形用スピニング装置の開発 -第二報 成形品形状に及ぼす成形要因の解析-
石田 啓輔; 守屋 進; 三田 和彦; 松田 清義; 佐久間 優; 村田 眞; 久保木 孝
Oral presentation, Japanese, 第61回塑性加工連合講演会講演論文集/日本塑性加工学会,第61回塑性加工連合講演会
Oct. 2010

管とリブの押出し接合における管肉厚とガイド位置が加工後の接合強度と成形品形状に及ぼす影響
諸井 努; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,第41回塑性加工春季講演会
May 2010

板材の新しいせん断加工における加工力について
路 大涛; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, English, 本塑性加工学会,日第41回塑性加工春季講演会
May 2010

極薄肉大径長尺管成形用スピニング装置の開発（第一報 動特性計測による成形条件の最適化）
三田 和彦; 守屋 進; 石田 啓輔; 佐久間 優; 村田 眞; 久保木 孝; 高橋 奈生人
Oral presentation, Japanese, 日本塑性加工学会,第41回塑性加工春季講演会
May 2010

側面圧縮における円管のへん平抑制
高橋 和仁; 久保木 孝; 村田 眞; 矢野 功造
Oral presentation, Japanese, 日本塑性加工学会,第41回塑性加工春季講演会
May 2010

加工履歴を有する金属材料の機械特性予測に関する研究
小栗 潤一; 村田 眞; 久保木 孝; 黒田 浩一; 寺田 賢二郎
Oral presentation, Japanese, 日本塑性加工学会,第41回塑性加工春季講演会
May 2010

V曲げ加工における5083厚板の形状精度に及ぼす曲げ型仕様の影響
ハムタ ナランバータル; 村田 眞; 久保木 孝; 柴田 隆浩; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,第41回塑性加工春季講演会
May 2010

1100板の新しいせん断加工におけるクリアランスの影響
路 大涛; 田中彰典; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 軽金属学会,第117回秋期大会
Nov. 2009

5083厚板のＶ曲げ加工における変形特性
ハムタ ナランバータル; 村田 眞; 久保木 孝; 柴田 隆浩; 金 英俊
Oral presentation, Japanese, 軽金属学会,第117回秋期大会
Nov. 2009

均等曲げにおける6063アルミニウム合金円管の変形挙動
高橋 和仁; 久保木 孝; 村田 眞
Oral presentation, Japanese, 軽金属学会,第117回秋期大会
Nov. 2009

アルミニウム円管と穴あきリブの押出し接合におけるリブ材質の影響
諸井 努; 久保木 孝; 村田 眞
Oral presentation, Japanese, 軽金属学会,第117回秋期大会
Nov. 2009

厚板のＶ曲げ加工における変形形状に及ぼす影響
ハムタ ナランバータル; 村田 眞; 久保木 孝; 柴田 隆浩; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,第60回塑性加工連合講演会
Oct. 2009

板材Ｖ曲げにおけるスプリングバックレス加工
柴田 隆浩; 金 英俊; 小山 純一; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,第60回塑性加工連合講演会
Oct. 2009

薄肉管とリブの押出し接合における押出し比の影響
諸井 努; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,第60回塑性加工連合講演会
Oct. 2009

板材の新しいせん断加工における切り口面について
路 大涛; 田中彰典; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,第60回塑性加工連合講演会
Oct. 2009

軸押力を付与した回転引曲げ加工における円管の肉厚変化が加工精度に与える影響
高橋 和仁; 久保木 孝; 村田 眞; 矢野 巧造
Oral presentation, Japanese, 日本塑性加工学会,第60回塑性加工連合講演会
Oct. 2009

バウシンガー効果を考慮した板曲げ時のスプリングバック予測
後藤 慎太郎; 村田 眞; 久保木 孝; 石上 圭介; 金 英俊; 小俣 均
Oral presentation, Japanese, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

内面に溝を有する管材の口絞り加工
天野 達也; 久保木 孝; 村田 眞; 奥井 達也
Oral presentation, Japanese, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

鋼板の新しいせん断加工における工具クリアランスの影響
田中 彰典; 路 大涛; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

線材の径が凹ロール伸線加工法に及ぼす影響 －第２報－
仙崎 泰慎; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

アルミニウム1070において前段変形履歴が機械特性に及ぼす影響
小栗 潤一; 村田 眞; 久保木 孝; 鶴田 浩基
Oral presentation, English, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

局部的な熱影響を受けた炭素鋼の残留応力解析
伊藤 敬; 村田 眞; 久保木 孝; 金 英俊; 李 若涛
Oral presentation, Japanese, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

薄肉管とリブの押出し接合における接合強度
諸井 努; 久保木 孝; 村田 眞
Oral presentation, English, 日本塑性加工学会,平成21年度塑性加工春季講演会
May 2009

5083厚板のＶ曲げにおける変形挙動
N.Khamt; 村田 眞; 久保木孝; 金 英俊; 柴田隆浩
Oral presentation, English, 軽金属学会
May 2009

アルミニウム円管と穴あきリブの押出し接合において管肉厚が成形品形状に及ぼす影響
諸井 努; 久保木孝; 村田 眞
Oral presentation, English, 軽金属学会,第116回春期大会
May 2009

1100板の新しいせん断加工における厚さの影響
路 大涛; 田中彰典; 金 英俊; 久保木孝; 村田 眞
Oral presentation, English, 軽金属学会,第116回春期大会
May 2009

曲げ荷重がボトミング加工の曲げ角度精度に及ぼす影響
柴田 隆浩; 金 英俊; 小山 純一; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

L曲げ加工におけるパンチの軌跡の影響（第2報）
金 英俊; 小山 純一; 今井 一成; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

アルミニウム円管と穴あきリブの押出し接合における管肉厚の影響
諸井 努; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

均等曲げによる円管の肉厚が断面変形に与える影響
高橋 和仁; 牟田 良輔; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

管材の肉厚が逃げ有りダイスを用いた口絞り加工に与える影響
小南 敦嗣; 村田 眞; 久保木 孝
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

しごきスピニング加工における極薄肉管の成形特性
高橋 奈生人; 久保木 孝; 村田 眞; 松田 清義; 三田 和彦
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

鋼板の新しいせん断加工における板厚の影響
田中 彰典; 村田 眞; 久保木 孝; 金 英俊
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

据え込み加工における時効硬化の影響
楊 陽; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

張出し加工における荷重線図を用いた応力－ひずみ線図の予測
森川 雄一; 小山 純一; 金 英俊; 尾形 敦; 村田 眞; 久保木 孝
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

引張圧縮試験における圧縮時の座屈対策を施した試験片形状の影響 -第２報-
石上 圭介; 久保木 孝; 村田 眞; 金 英俊; 小俣 均; 山谷 泰司
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

炭酸ガスレーザ切断後の鋼板の特性
李 若涛; 金 英俊; 小山 純一; 石黒 宏明; 村田 真; 久保木 孝
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

加工履歴を有するアルミニウム材の機械特性の予測法
鶴田 浩基; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

線材の径が凹型ロールを用いた伸線加工法に及ぼす影響
仙崎 泰慎; 久保木 孝; 村田 眞
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

管の矯正加工における断面形状の変化
山口 洋平; 天野 達也; 久保木 孝; 村田 眞; 山川 富夫; 黒田 浩一
Oral presentation, Japanese, 塑性加工学会,第59回塑性加工連合講演会
Nov. 2008

1100アルミニウム板材の新しいせん断加工における板厚の影響
村田眞; 久保木孝; 田中彰典; 金英俊
Oral presentation, Japanese, 軽金属学会,平成20年度軽金属学会 第115回秋期大会
Nov. 2008

塑性加工と強度
久保木 孝
Others, Japanese, 第14期非線形CAE勉強会, 非線形CAE協会
Nov. 2008

凹ロールを用いたフリーサイズ伸線加工法の提案
久保木 孝; 中村 友彦; 菅原 弘匡; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
Jun. 2008

板材の新しいせん断加工
村田 眞; 久保木 孝; 金 英俊; 田中 彰典
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

引張圧縮試験における試験片形状の検討
石上 圭介; 久保木 孝; 村田 眞; 金 英俊; 小俣 均; 山谷 泰司
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

1050アルミニウムのリブ接合押出しにおける温度の影響
諸井 努; 久保木 孝; 仙崎 泰慎; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

逃げ有りダイスの接触面数がA1050円管の口絞りに与える影響
小南 敦嗣; 大出 佑亮; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

均等曲げによる管の断面変形に関する研究
田中 彰典; 高橋 和仁; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

回転引曲げ加工の軸押し力によるへん平化の抑制
高橋 和仁; 紀頭 航; 久保木 孝; 村田 眞; 小野 数彦; 矢野 巧造
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

L曲げ加工におけるパンチの軌跡の影響
金 英俊; 小山 純一; 今井 一成; 久保木 孝; 村田 眞
Oral presentation, Japanese, 日本塑性加工学会,平成20年度(第39回)塑性加工春季講演会
May 2008

「NAGOYA TUBE 2007とその研究開発トピックス」
久保木 孝
Oral presentation, Japanese, 塑性加工学会 チューブフォーミング分科会 第117回研究会
Mar. 2008

張り出し加工における荷重線図を用いた応力－ひずみ曲線の予測
小山純一; 金英俊; 村田眞; 久保木孝; 森川雄一
Oral presentation, Japanese, 日本塑性加工学会,第５８回塑性加工連合講演会
Oct. 2007

リブ接合押出しの変形特性の数値解析
諸井努; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,第５８回塑性加工連合講演会
Oct. 2007

円管のプレス曲げにおける加工硬化指数の影響
村田眞; 久保木孝; 金英俊; モハマド グダルディ
Oral presentation, Japanese, 日本塑性加工学会,第５８回塑性加工連合講演会
Oct. 2007

口絞り成形品の機械特性の予測方法
鶴田浩基; 久保木孝; 村田眞; 永瀬豊; 高部秀樹; 黒田浩一; 秋山雅義
Oral presentation, English, 日本塑性加工学会,第５８塑性加工連合講演会
Oct. 2007

オーバルダイスの形状が円管の回転口絞り加工における成形形状に及ぼす影響
大出佑亮; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,第５８塑性加工連合講演会
Oct. 2007

回転引曲げ加工の軸押し力が曲げ品質に与える影響
高橋和仁; 渡邊峻士; 久保木孝; 村田眞; 小野数彦; 矢野巧造
Oral presentation, Japanese, 日本塑性加工学会,第５８塑性加工連合講演会
Oct. 2007

リブ接合押出しにおいて，管肉厚がメタルフローに及ぼす影響
諸井努; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,平成19年度塑性加工春季講演会
May 2007

円管の回転口絞り加工においてダイス形状が加工限界に及ぼす影響
大出佑亮; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,平成19年度塑性加工春季講演会
May 2007

スキンパス法による薄肉円管の残留応力低減
久保木孝; 山下弘高; 榊友広; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,平成19年度塑性加工春季講演会
May 2007

中炭素鋼のパーライト形態を考慮した時効進行の予測法に関する研究
楊陽; 三宅章生; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,平成19年度塑性加工春季講演会
May 2007

打ち抜き加工による応力ひずみ曲線の予測
森川雄一; 金英俊; 小山純一; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,平成19年度塑性加工春季講演会
May 2007

非軸対称ダイスによる円管の回転口絞り加工
久保木 孝; 大出 佑亮; 村田 眞
Oral presentation, Japanese, 第114 回チューブフォーミング分科会研究例会
Mar. 2007

心金引きにおける残留応力抑制
榊友広; 山下弘高; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会 伸線技術分科会,第62回伸線技術分科会研究会
Nov. 2006

リブ接合押出し法に置いてマンドレル形状がメタルフローに及ぼす影響
諸井努; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Oct. 2006

引張り曲げ加工における断面形状の変化
高橋和仁; 松下陽亮; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Oct. 2006

ケブラー線とアルミニウムによる複合材料の機械的性質
植松俊一; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Oct. 2006

回転口絞り加工において円管とダイスの接触面積が加工限界に及ぼす影響
大出佑亮; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Oct. 2006

ﾐｸﾛ組織を考慮した中炭素鋼の冷間加工におけるひずみ時効進行を予測する方法の提案
三宅章生; 高田恵美; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会 伸線技術分科会,第61回伸線技術分科会研究集会
Jun. 2006

Influence of Material Properties on Shear Bending Process of Circular Tubes
グダラズィ モハマド; 久保木孝; 村田眞
Oral presentation, English, 日本塑性加工学会
May 2006

非軸対称ダイスを用いた円管の口絞り加工
大出佑亮; 木村康彦; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工学会春季講演会
May 2006

アルミニウムとステンレス線による複合材料の機械的性質
植松俊一; 村田眞; 久保木孝
Oral presentation, Japanese, 塑性加工学会春季講演会
May 2006

逐次打点曲げにおける曲げ半径の算出
金英俊; 山田拓夫; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工学会春季講演会
May 2006

可変曲げ半径ダイスを用いた管材の引張曲げの加工特性
高橋和仁; 松下亮介; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工学会春季講演会
May 2006

穴のあいたリブを有する円管の製作
諸井努; 高岡大和; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工学会春季講演会
May 2006

管のプラグ引きにおける残留応力抑制方法
榊友広; 西田圭吾; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工学会春季講演会
May 2006

The Effect of Tube Thickness on the Shear Bending Processs of Circular Tubes
グダラズィ モハマド; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2005

口絞りにおいて加工条件が加工限界におよぼす影響
久保木孝; 村田眞; 木村康彦
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2005

逐次打点法によるアングル材の曲げにおけるウェブ高さの影響
山田拓央; 金英俊; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2005

逐次打点法による平板面内曲げに及ぼすパンチの打撃角度の影響
金英俊; 山田拓央; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2005

有限要素法による円管のＭＯＳ曲げ加工特性
村田眞; 高橋和仁; 久保木孝; 金英俊
Oral presentation, Japanese, 日本鉄鋼協会,第150回秋季講演大会
Sep. 2005

非対称ダイスを用いた円管の口絞り加工
木村康彦; 村田眞; 久保木孝
Oral presentation, Japanese, 日本機械学会,２００５年度年次大会
Sep. 2005

マグネシウム管のスピニングによる縮管
村田眞; 久保木孝
Oral presentation, English, 日本機械学会,２００５年度年次大会
Sep. 2005

円管のせん断曲げ加工
モハマド・グッダルジィ; 久保木孝; 村田眞
Oral presentation, Japanese, 日本機械学会,２００５年度年次大会
Sep. 2005

管の引抜き加工における残留応力抑制法
久保木孝; 榊友広; 村田眞
Oral presentation, Japanese, 日本機械学会,２００５年度年次大会
Sep. 2005

棒線材の２ロール矯正加工
佐々木哲也; 久保木孝; 村田眞
Oral presentation, Japanese, 日本機械学会,２００５年度年次大会
Sep. 2005

テーパマンドレルを用いた偏肉厚押出し加工の有限要素シミュレーション
牧山高大; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演会
May 2005

The Effect of Die Corner Radius on the Shear Bending Process of Circular Tubes
グダラズィ モハマド; 松下陽亮; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演会
May 2005

アングル材の逐次打点曲げにおける押込み量の影響
金英俊; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演会
May 2005

逐次打点法によるアングル材の曲げにおける打撃ピッチの影響
山田拓央; 金英俊; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演会
May 2005

面内逐次打点曲げ加工において平板材質が加工特性に及ぼす影響
金英俊; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2004

テーパマンドレルとチョーク付きダイスを用いた円管の偏肉厚押出し加工
牧山高大; 高岡大和; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2004

円管のせん断曲げ加工の数値シミュレーション
グダラジィ モハマド; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2004

口絞り加工において加工条件が応力に及ぼす影響
木村康彦; 村田眞; 久保木孝; 下田健
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2004

正方形管のスピニング加工における経路の影響
荒生ひとみ; 開俊介; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2004

ミクロ組織を考慮した中炭素鋼のひずみ時効進行の予測法
三宅章生; 高田恵美; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2004

矯正中の押込み量が真直性に及ぼす影響
佐々木哲也; 久保木孝; 村田眞
Oral presentation, Japanese, 塑性加工学会,塑性加工学会伸線技術分科会研究会
Jun. 2004

高圧水を用いた鋼鈑の深絞り
Makoto Murata; Takashi Kuboki; Hiroyuki Kudou
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演会
May 2004

平板の面内逐次打点曲げに及ぼすピッチの影響
金英俊; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工学会春季講演大会
May 2004

正方形管のスピニング加工特性
荒生ひとみ; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演大会
May 2004

テーパ形状のマンドレルを用いた円管の偏肉厚押出し加工におけるダイス先端形状の影響
牧山高大; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演大会
May 2004

小さい曲げ半径での円管のせん断曲げ
グダラジィ モハマド; 久保木孝; 村田眞
Oral presentation, Japanese, 日本塑性加工学会,塑性加工春季講演大会
May 2004

平板の面内逐次打点曲げにおける押込み量の影響
金英俊; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,添え以下鋼連合講演会
Nov. 2003

連続伸線における低角度ダイス適用によるボイド抑制効果
久保木孝; 根石豊; 秋山雅義
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2003

テーパ上のマンドレルを用いた円管の偏肉押出し加工におけるダイス形状の影響
牧山高大; 村田眞; 久保木孝
Oral presentation, Japanese, 日本塑性加工学会,塑性加工連合講演会
Nov. 2003

高圧水を利用した冷延鋼板による深絞り加工
工藤寛之; 久保木孝; 村田眞
Oral presentation, Japanese, 塑性加工春季講演会論文集
May 2003

熱間ローラによるマグネシウム合金管材のスピニングにおける加工限界
横田靖央; 久保木孝; 村田眞
Oral presentation, Japanese, 塑性加工春季講演会論文集
May 2003

平板の面内逐次打点曲げにおける打撃角度の影響
金英俊; 久保木孝; 村田眞
Oral presentation, Japanese, 塑性加工春季講演会論文集
May 2003

Levelling Effect of Residual Stress by an Ultra-light Reduction at the Final Stage of Bar Drawing Process
Takashi Kuboki
Others, English, Asia Youth Forum on Advanced Manufacturing in Japan, Asia Youth Forum on Advanced Manufacturing in Japan
Mar. 2003

Levelling Effect of Residual Stress by an Ultra-light Reduction at the Final Stage of Bar Drawing Process
Takashi Kuboki
Others, English, Asia Youth Forum on Advanced Manufacturing in Japan, Asia Youth Forum on Advanced Manufacturing in Japan
Mar. 2003

硬度を指標とする冷間鍛造割れ予測
久保木孝
Invited oral presentation, Japanese, 塑性加工学会鍛造分科会, 塑性加工学会鍛造分科会
Jun. 2002

硬度を指標とする冷間鍛造割れ予測
久保木孝
Invited oral presentation, Japanese, 塑性加工学会鍛造分科会
Jun. 2002

冷間圧縮加工時の割れ発生予測式
渡部了; 春畑美文; 久保木孝; 根石豊
Oral presentation, Japanese, 第52回塑性加工連合講演会
Nov. 2001

矯正条件が材料の真直性に及ぼす影響
久保木孝; 阿部正昭; 秋山雅義
Oral presentation, Japanese, 日本鉄鋼協会第142回秋季講演大会
Oct. 2001

入側素材の曲率が引抜き後の材料真直性に及ぼす影響
久保木孝; 古田治弘; 黒田浩一
Oral presentation, Japanese, 日本鉄鋼協会第142回秋季講演大会
Oct. 2001

冷間加工時の割れ発生限界に及ぼす予ひずみの影響(冷間鍛造性評価技術-2)
渡部了; 根石豊; 久保木孝
Oral presentation, Japanese, 日本鉄鋼協会第142回秋季講演大会
Oct. 2001

冷間押出しにおける内部割れ発生に及ぼす加工条件の影響
黒田浩一; 久保木孝; 古田治弘; 渡部了
Oral presentation, Japanese, 日本鉄鋼協会第142回秋季講演大会
Oct. 2001

鋼の微視構造に起因した巨視的力学挙動に関する考察
松井和己; 及川兼司; 寺田賢二郎; 秋山雅義; 久保木孝
Oral presentation, Japanese, 日本機械学会材料力学部門講演会講演論文集
Sep. 2001

鋼の微視的構造に起因する巨視的弾塑性特性に関する考察
及川兼司; 松井和己; 寺田賢二郎; 秋山雅義; 久保木孝
Oral presentation, Japanese, 計算工学講演論文集
May 2001

入側素材の曲率が引抜き後の材料真直性に及ぼす影響
古田治弘; 吉川肇; 久保木孝
Oral presentation, Japanese, 日本金属学会九州支部・日本鉄鋼協会九州支部共催
Mar. 2001

引抜き材の非軸対称切削時の曲がり抑制に関する検討
渡部了; 阿部正昭; 久保木孝
Oral presentation, Japanese, 第51回塑性加工連合講演会
Nov. 2000

管材のダイレスＵベンド法の開発
久保木孝
Invited oral presentation, Japanese, 塑性加工学会チューブフォーミング分科会, 塑性加工学会チューブフォーミング分科会
Oct. 1998

管材のダイレスＵベンド法の開発
久保木孝
Invited oral presentation, Japanese, 塑性加工学会チューブフォーミング分科会
Oct. 1998

管材のダイレスＵベンド法の開発, 塑性加工春季講演会
久保木孝; 古堅宗勝; 逢阪慎一郎; 小野秀敏
Oral presentation, Japanese, 塑性加工春季講演会
May 1998

剛塑性ＦＥＭを用いた条鋼のタンデム圧延の数値解析, 塑性加工春季講演会
久保木孝; 黒田浩一; 本田英二
Oral presentation, Japanese, 塑性加工春季講演会
May 1997

Siのワイヤソー連続切断におけるウエハ厚さ変動とその抑制方法の検討
久保木孝; 小嶋正康
Oral presentation, Japanese, 精密工学会秋季大会学術講演会
Sep. 1994

石英のワイヤソー連続切断におけるウエハ厚さ精度
久保木孝; 小嶋正康
Oral presentation, Japanese, 精密工学会秋季大会学術講演会
Sep. 1993

石英の一方向マルチワイヤソー切断における切断荷重(第二報)
久保木孝; 小嶋正康
Oral presentation, Japanese, 精密工学会春季大会学術講演会
Mar. 1993

石英の一方向マルチワイヤソー切断における切断荷重
久保木孝; 小嶋正康
Oral presentation, Japanese, 精密工学会春季大会学術講演会
Mar. 1992

Fundamentals of Mechanical Working
The University of Electro-Communications

生産加工学基礎
電気通信大学

Mechanics of Materials,Theory and Practice
The University of Electro-Communications

材料力学および演習
電気通信大学

Manufacturing Technology, Theory and Practice
The University of Electro-Communications

加工学および演習
電気通信大学

Numerical Analysis
The University of Electro-Communications

数値解析
電気通信大学

Aug. 2023
CIRP(Int. Council Production Research), Fellow

日本精密工学会

日本軽金属学会

The Society of Materials Science, Japan

Institution of Mechanical Engineers

The Iron and Steel Institute of Japan

The Japan Society for Technology of Plasticity

The Japan Society of Machanical Engineers

Development of wood forming method with high hydrostatic pressure that achieves large deformation and high strength
梶川 翔平; 久保木 孝
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), 22K04773
01 Apr. 2022 - 31 Mar. 2025

Circular Tube with Holed Rib by Extrusion
MURATA Makoto; KUBOKI Takashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), 穴付きリブを有する管を製造するための押出し加工機を試作し,押出加工の実験を行った.押出し加工の数値解析を行い,この加工法の特徴を明らかにした. 管材の成形において重要となる管肉厚が,本加工法において成形に与える影響について検討を加えた.部材を鉛とアルミニウムとした.管肉厚が薄くなると押出し比が増加し,接合に適したガイド位置が低くなる.薄肉薄においても加工条件を適正化することで厚肉管と同様に,接合強度の向上が確認できた.さらに,リブと管の接合強度についても実験的に調べ,最適値の検討を行った.管の形状を円形にしているが,ガイド位置等がこの断面形状に及ぼす影響とその理由について検討を行った.数値解析により薄肉化とガイド位置の変化による成形品への影響を調べ,リブの変形量を定量的に示した.このことによって,リブと管の接合強度や加工精度が最適となる加工条件を明らかにした., 19560721
2007 - 2009

マニピュレータ
Patent right, 久保木 孝, 高橋 和仁, 坪内 翼, 特願2014-104266, Date applied: 20 May 2014, 特開2015-218849, Date announced: 07 Dec. 2015, 特許第6422148, Date issued: 26 Oct. 2018

シート状ワークの切断方法及び装置
Patent right, 小山 純一, 金 英俊, 村田 眞, 久保木 孝, 特願2008-118703, Date applied: 30 Apr. 2008, 特開2009-269092, Date announced: 19 Nov. 2009, 特許5224892, Date issued: 22 Mar. 2013

管材製造装置、管材製造方法、および、管材
Patent right, 村田 眞, 久保木 孝, 諸井 努, 特願2011-112537, Date applied: 19 May 2011, 特開2012-240084, Date announced: 10 Dec. 2012

材料の応力歪関係予測方法、材料の加工方法および材料の応力歪関係予測装置
Patent right, 小山純一, 金 英俊, 久保木 孝, 村田 眞, 特願2007-299217, Date applied: 19 Nov. 2007, 特許5140388, Date issued: 12 Nov. 2012

曲げ加工装置および曲げ加工方法
Patent right, 特願2011-065926, Date applied: 24 Mar. 2011, 特開2012-200741, Date announced: 22 Oct. 2012

押出加工物の製造方法及び押出加工物
Patent right, 村田 眞, 久保木 孝, 牧山 高大, 特願2004-108602, Date applied: 04 Mar. 2004, 特許4324671, Date issued: 19 Jun. 2009

金属円管の口絞り加工方法および口絞り加工用ダイス
Patent right, 久保木 孝, 村田 眞, 木村 康彦, 特願2005-236781, Date applied: 17 Aug. 2005, 特許公開2007-050423, Date announced: 01 Mar. 2007