KINDAI UNIVERSITY


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NISHIYABU Kazuaki

Profile

FacultyDepartment of Mechanical Engineering / Graduate School of Science and Engineering Research
PositionProfessor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/923-nishiyabu-kazuaki.html
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Mail
Last Updated :2020/04/03

Education and Career

Education

  •   1982 04  - 1986 03 , Kinki University, Faculty of Science and Engineering
  •   1986 04  - 1988 03 , Kinki University, Graduate School of Science and Engineering Research
  •   1997 04  - 1999 03 , Osaka University, Graduate School of Engineering

Academic & Professional Experience

  •   2016 04 ,  - 現在, Professor, Faculty of Science and Technology, Kindai Uiniversity
  •   2010 04 ,  - 2016 03 , Associate Professor, Faculty of Science and Engineering, Kinki University
  •   2005 04 ,  - 2010 03 , Associate Professor, Industrial Systems Engineering, Osaka Prefectural College of Technology
  •   1998 04 ,  - 2005 03 , Associate Professor, Department of Mechanical Engineering, Osaka Prefectural College of Technology Industrial Systems Engineering
  •   1999 04 ,  - 1999 09 , Guest Professor, Department of Metals and Materials, Katholieke Universiteit Leuve
  •   1991 04 ,  - 1998 03 , Lecturer, Department of Mechanical Engineering, Osaka Prefectural College of Technology
  •   1992 04 ,  - 1993 03 , Reseacher, Division of Material Technology, Osaka Prefectural Industrial Technical Research Institute
  •   1988 04 ,  - 1991 03 , Research Associate, Department of Mechanical Engineering, Osaka Prefectural College of Technology

Research Activities

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Machine materials and mechanics
  • Nanotechnology/Materials, Material fabrication and microstructure control
  • Nanotechnology/Materials, Composite materials and interfaces
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Manufacturing and production engineering
  • Nanotechnology/Materials, Nano/micro-systems
  • Nanotechnology/Materials, Nanomaterials

Research Interests

  • MIM

Published Papers

  • Behavior of Debinding and Sintering in Micron and Submicron-Sized Copper Powder Injection Molded Parts, NISHIYABU KAZUAKI, TANABE DAIKI, KANOKO YASUHIRO, TANAKA SHIGEO, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A (Web), TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A (Web), 79(807), WEB ONLY 1593-1603, 2013 , Refereed
  • Fabrication of Micro-Structured Parts by Nano-Imprint Lithography Sacrificial Plastic Mold Insert MIM Using Nano-Sized Copper Powder, NISHIYABU Kazuaki, TANABE Daiki, KANOKO Yasuhiro, TANAKA Shigeo, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 77(780), 1378 - 1387, 2011 , Refereed
    Summary:This study aims to develop the manufacturing method of micro-structured parts by the metal powder injection molding (MIM) inserted micro-sacrificial plastic molds which were prepared by nano-imprint lithography (NIL) technique. In this process named NIL/μ-SPiMIM, the feedstock composed of nano-sized copper powder and polyacetal-based binder was adequately prepared and molded into polymethylmethacrylate films with fine line-scan structures, and the molded parts were sintered in a reductive gas atmosphere followed by solvent debinding of the films. The behavior in debinding and sintering was investigated by thermo-gravimetric analysis, carbon and oxygen analysis and SEM observation. The effects of sintering temperature on sintered density, shrinkage, and profile accuracy were evaluated systematically. It can be concluded that the manufacturing method named NIL/μ-SPiMIM proposed in this study has great potential to produce precisely 3 dimensional complex metallic parts with fine micro-structures.
  • Effect of Micro/Nano Powder Ratio on the Properties of Copper Sintered Parts Produced by Metal Injection Molding, NISHIYABU Kazuaki, KAKISHITA Kenichi, TANAKA Shigeo, Transactions of the Japan Society of Mechanical Engineers. A, Transactions of the Japan Society of Mechanical Engineers. A, 76(767), 996 - 1001, Jul. 2010 , Refereed
    Summary:In microminiaturization of metal injection molding, the use of finer metal powders is one of solutions for improving the dimensional accuracy and surface roughness of sintered products. This study aims to investigate the effects of micro/nano powder ratio on the properties of sintered parts in μ-MIM process. A novel experimental machine which can achieve to mold without pelletizing was used to produce the tiny specimens with high trial efficiency and a small amount of feedstock. Small dumbbell specimens were produced with changing the binder content and the fraction of micro/nano copper powders. The effects of nano copper powder addition on the tap density of mixed powder, the viscosity of MIM feedstock and the grain size, surface roughness and tensile strength of sintered parts were revealed.
  • Fabrication of micro porous metal components by metal injection molding based powder space holder method, Nishiyabu Kazuaki, Matsuzaki Satoru, Tanaka Shigeo, HIGH TEMPERATURE MATERIALS AND PROCESSES, HIGH TEMPERATURE MATERIALS AND PROCESSES, 26(4), 257 - 267, 2007 , Refereed
  • Micro metal injection molding using hybrid micro/nano powders, Nishiyabu Kazuaki, Kakishita Kenichi, Tanaka Shigeo, PROGRESS IN POWDER METALLURGY, PTS 1 AND 2, PROGRESS IN POWDER METALLURGY, PTS 1 AND 2, 534-536, 381 - 384, 2007 , Refereed
  • Innovations in micro metal injection molding process by lost form technology, Nishiyabu Kazuaki, Kanoko Yasuhiro, Tanaka Shigeo, PROGRESS IN POWDER METALLURGY, PTS 1 AND 2, PROGRESS IN POWDER METALLURGY, PTS 1 AND 2, 534-536, 369 - 372, 2007 , Refereed
  • Gas nitriding mechanism in titanium powder injection molded products, Osada Toshiko, Miura Hideshi, Yamagami Takanobu, Nishiyabu Kazuaki, Tanaka Shigeo, PROGRESS IN POWDER METALLURGY, PTS 1 AND 2, PROGRESS IN POWDER METALLURGY, PTS 1 AND 2, 534-536, 361 - 364, 2007 , Refereed
  • Preparation of Flexible Interphase in FRP and Determination of the Finite Thickness(Special Issue on Composite Materials), OYA Naoyuki, NISHIYABU Kazuaki, HAMADA Hiroyuki, Journal of the Society of Materials Science, Japan, Journal of the Society of Materials Science, Japan, 51(5), 483 - 488, May 2002 , Refereed
    Summary:This paper describes experimental developments for a concise preparation method of flexible interphase in commonly used GFRP and determination methods of the finite interphase thickness. The preparation scheme of the flexible interphase basically comprises surface coating of glass fibres with toughened epoxy resin. The finite thickness of the flexible interphase is determined by means of scanning electron microscopy equipped with energy dispersive X-ray element analyser and visco-elasticity image analysis featured in a scanning probe microscope. Certain evidences are successfully observed for the flexible interphase to be created by means of the proposed preparation method. However, it is found that the interphase thickness obtained from each method exhibits different values due to the particular sample status. The model composite used in the X-ray method contains a platinum layer as a boundary-indicator between the flexible interphase and the matrix resin. The platinum layer may hinder the interacting diffusion between the interphase and the matrix during the curing process, and this probably causes the broader interphase to remain in the model composite used in the X-ray method. Both methods are found to be useful to evaluate the interphase thickness around the single glass-filament at the microscopic level. However, those results show relatively large scatters ; this means that more efforts are still needed to create the interphase uniformly around the glass fibres using more sophisticated surface treatment techniques.

Books etc

  • Recent Development in Research of Macro- and Nanoporous Metals, 分担執筆,   2010 07

Conference Activities & Talks

  • 電気抵抗式融着によるCF/PPS積層板の接合挙動に及ぼす影響因子, 田邉大貴, 倉敷哲生, 傳谷真司, 西籔和明, 日本複合材料合同会議(CD-ROM),   2013
  • 電気抵抗式融着による熱可塑性CFRP板の接合挙動, 田邉大貴, 傳谷真司, 西籔和明, 倉敷哲生, 日本繊維機械学会年次大会研究発表論文集・講演要旨集,   2013
  • Alシート/熱可塑性CFRPハイブリッド積層板の熱変形挙動, 森椙哲也, 服部佑紀, 西籔和明, 日本複合材料合同会議(CD-ROM),   2013
  • ESナノファイバーインプリント樹脂型ナノ粉末印刷によるマイクロ構造体の作製, 桜井晋也, JUSOH Mohd, Ikhwan Helmi, 西籔和明, 日本複合材料合同会議(CD-ROM),   2013
  • 形状記憶合金ワイヤを用いた熱可塑性CFRP板の作製とその形状回復挙動, 田渕喜瑛, 西籔和明, 田邉大貴, 倉敷哲生, 日本複合材料合同会議(CD-ROM),   2013
  • Fabrication and Thermal Conductivity of Diamond Particle Added Nano-Copper Powder Sintered Parts,   2011 11
  • Metal Injection Moulding Process for Copper / Diamond Composites with High Thermal Conductivity by Using Nanopowder, PM2010 WORLD CONGRESS,   2011 10 , PM2010 WORLD CONGRESS
  • 軟磁性粉末射出成形体の充填密度に及ぼす材料および射出成形条件の影響, 増永賢司, 西籔和明, 森本純司, 橋本知久, 田中茂雄, 日本機械学会年次大会講演論文集,   2011 09 10
  • ナノ銅粉末を用いたナノインプリント樹脂型インサートMIMによるマイクロ構造体の製造法, 西籔和明, 田邉大貴, 鹿子泰宏, 田中茂雄, 日本機械学会年次大会講演論文集,   2011 09 10
  • 織物強化熱可塑性複合材料の片持ち曲げ変形に及ぼす繊維配向角と温度負荷の影響, 吉澤賢宏, 田邉大貴, 西籔和明, 倉敷哲生, 日本機械学会年次大会講演論文集,   2011 09 10
  • 犠牲樹脂型インサート金属粉末射出成形によるインプリント用スタンパーの開発, 大久保健児, 田中茂雄, 伊藤浩志, 西籔和明, 日本機械学会年次大会講演論文集,   2011 09 10
  • Report on "JSMS COMPOSITES Young Researcher Symposium, 2011", NISHIYABU Kazuaki, Journal of the Society of Materials Science, Japan,   2011
  • Report on "JSMS COMPOSITES Young Researcher Symposium, 2010", KURASHIKI Tetsusei, NISHIYABU Kazuaki, Journal of the Society of Materials Science, Japan,   2011
  • 335 Fabrication and Thermal Conductivity of Diamond Particle Added Nano-Copper Powder Sintered Parts, KANOKO Yasuhiro, TANAKA Shigeo, TANABE Daiki, NISHIYABU Kazuaki, Materials and processing conference,   2010 11 27
    Summary:This study aims to develop the MIM process for manufacturing the micro heat sinks made of copper / diamond composites with high thermal conductivity. Diamond particles were added into the feedstock composed of copper powder and polyathetal-based binder. The compound feedstock was molded into sacrificial plastic mold (SP-mold), and the green compacts with micro-pillars were obtained and removed the SP-mold by solvent extraction. Nano-sized copper powder was used for drastically decreasing the sintering temperature to prevent from occurring thermal damages on the surfaces of diamond particles. The sintered parts were also prepared by spark plasma sintering in contrast with furnace sintering, and they were evaluated by density and thermal conductivity measurements. The experimental results showed that using nanopowder could obtain a sufficient high sintered density under low sintering temperature.
  • Micro Metal Injection Moulding by NIL Lost Form Technology and Using Nanopowder, PM2010 WORLD CONGRESS,   2010 10 , PM2010 WORLD CONGRESS
  • Fabrication and Thermal Properties of Diamond Particle Added Nano-Copper Powder Sintered Parts,   2010 08
  • Evaluation of Anisotropic Behavior in Bending Deformation of CFRP Laminates Under Concentrated Load,   2010 08
  • 407 Study on Electro-Fusion Joining Property of Cross-Linked Polyethylene Pipes, MUTO Masahiro, NISHIYABU Kazuaki, WATANABE Takashi, Materials and processing conference,   2009 11 06
  • 216 Evaluation on Anisotropic Behavior in Bending Deformation of CFRP Laminates Under Concentrated Load, OHARA Ayatoshi, NAKAO Yuki, NISHIYABU Kazuaki, Materials and processing conference,   2009 11 06
  • W01(10) Feasibility Study on Micro and High Functional Processings by Metal Powder Injection Molding, NISHIYABU Kazuaki,   2007 09 07
    Summary:The possibility of micro and high functional processings by metal powder injection molding (MIM) which uses effectively polymeric materials for enhancing both mold-ability and shape-retention were introduced. Sacrificial plastic mold inserted metal injection molding (SPiMIM) was developed to overcome some problems facing the realization of μ-MIM process. The molds were manufactured by LIGA process. Two types of transcription methods were adopted in LIGA/μ-SPiMIM process to obtain the sintered parts with multi pillars or fluidic channels. The effects of particle size on the quality of micro-structured parts were also investigated.
  • Examples of Non-contact Strain Field Measurement by Advanced Digital Images Correlation Technique, Nishiyabu Kazuaki, Akabane Takahiko, Nonaka Hiroshi, Symposium on Evaluation and Diagnosis,   2003 12 02
  • Numerical Approach for Evaluation of Stress Transmissibility on Composite Interface, NISHIYABU Kazuaki, YOKOYAMA Atsushi, HAMADA Hiroyuki,   1996 05 13

Misc

  • CFRP量産成形研究の最前線 インダストリアルCFRPの用途拡大に向けた最新の技術動向と製造技術, 西籔和明, ぷらすとす, 1, 7, 493‐497,   2018 07 25 , http://jglobal.jst.go.jp/public/201802213424272755
  • Cutting Edge of Molding Techniques of Composite Materials I: Latest Manufacturing Cases and Researches of Carbon Fiber Reinforced Thermoplastics in Europe, 西籔和明, 田邉大貴, 材料, 67, 6, 653‐659(J‐STAGE), 659,   2018 06 01 , 10.2472/jsms.67.653, http://jglobal.jst.go.jp/public/201802219667598967
  • 産学官連携を活かした金型・成形技術の高度化と人材育成 Part1:研究機関が実施する技術開発・人材育成支援〈事例4〉近大発・大阪東部地域連携における先進的な金型技術の高度化研究プロジェクト, 西籔和明, 型技術, 32, 11, 036‐039,   2017 10 01 , http://jglobal.jst.go.jp/public/201702280321164737
  • 湿式圧縮成形による炭素繊維熱可塑性エポキシ樹脂積層板の作製, 嶋田翔太, 田邉大貴, 西籔和明, 日本機械学会年次大会講演論文集(CD-ROM), 2017, ROMBUNNO.J0440305,   2017 09 02 , http://jglobal.jst.go.jp/public/201802216010140221
  • 電気式融着接合した織物CF/PPS積層板の引張せん断強度に及ぼす影響因子, 窪堀文夫, 田邉大貴, 西籔和明, 日本機械学会年次大会講演論文集(CD-ROM), 2017, ROMBUNNO.J0440204,   2017 09 02 , http://jglobal.jst.go.jp/public/201802238869039597
  • 近赤外線加熱を用いた熱可塑性CFRPプリプレグテープの自動積層成形, 田邉大貴, 中田直樹, 西籔和明, 日本機械学会年次大会講演論文集(CD-ROM), 2017, ROMBUNNO.J0440304,   2017 09 02 , http://jglobal.jst.go.jp/public/201802297721162196
  • 次世代繊維~セルロースナノファイバーから人工クモ糸まで~熱可塑性CFRPとマルチマテリアル化の最新技術動向, 西籔和明, 化学経済, 64, 8, 36‐42,   2017 07 01 , http://jglobal.jst.go.jp/public/201702254278582969
  • 部品軽量化のための金型・成形技術と材料技術 インダストリアルCFRPの最新技術動向―異なるものとのつながりの重要性―, 西籔和明, 型技術, 32, 7, 022‐026,   2017 06 01 , http://jglobal.jst.go.jp/public/201702281088173900
  • ハイブリッド射出成形により作製された熱可塑性CFRPの接合強度特性評価, 松村亮太, 田邉大貴, 田邉大貴, 西籔和明, 日本機械学会年次大会講演論文集(CD-ROM), 2016, ROMBUNNO.J0450104,   2016 09 10 , http://jglobal.jst.go.jp/public/201602279759175072
  • 熱可塑性CFRP積層板の電気式融着接合に及ぼす炭素繊維抵抗発熱体の影響, 田邉大貴, 田邉大貴, 窪堀文夫, 西籔和明, 倉敷哲生, 日本機械学会年次大会講演論文集(CD-ROM), 2016, ROMBUNNO.J0450202,   2016 09 10 , http://jglobal.jst.go.jp/public/201602282375876653
  • Effects of fiber reinforcement pattern on high frequency induction heating behavior of unidirectional and woven CFRTP laminates, Daiki Tanabe, Kai Kurauchi, Kazuaki Nishiyabu, Tetsusei Kurashiki, Zairyo/Journal of the Society of Materials Science, Japan, 65, 611, 617,   2016 08 01 , 10.2472/jsms.65.611, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84983661905&origin=inward
    Summary:©2016 The Society of Materials Science. This study aims to reveal the induction heating behavior of CFRTP composites by high-frequency induction heating method. The material used is unidirectional CF/PPS (UD-CF/PPS) and satin weave CF/PPS (woven-CF/PPS) laminates. The effects of geometry of induction coils, coil height, heating time and the carbon fiber reinforcement of CFRTP laminates on heating behavior of CFRTP composites in induction heating were investigated. The experimental results revealed that the surface temperature of UD-CF/PPS and woven-CF/PPS laminates was increased with increasing the heating time. Moreover, the surface temperature was increased with decreasing remarkably the coil distance. It was also confirmed that the carbon fiber reinforcement of CFRTP laminates has an effect on induction heating behavior.
  • Continuous tape layup molding of CFRTP using near-infrared heating and high frequency induction roller heating, D. Tanabe, F. Kubohori, S. Imamura, H. Jiang, K. Nishiyabu, T. Kurashiki, ECCM 2016 - Proceeding of the 17th European Conference on Composite Materials,   2016 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85018615008&origin=inward
    Summary:© 2016, European Conference on Composite Materials, ECCM. All rights reserved. This study focused on the heating behavior, thermal distribution and interlaminar shear strength in a laying process of unidirectional carbon fiber reinforced thermoplastic tape to predict the optimum processing condition for carbon fiber prepreg tape laying. The material used for the experiment was unidirectional CF/PA6 prepreg tape. The source of heat was used near infrared heating and high frequency induction roller heating. The effects of processing conditions such as the position of infrared heaters, feed speed of prepreg tape and temperature of compaction roller on the laying behavior of prepreg tape and their bonding strength were investigated. From the experimental results, it was found that the near infrared heating was required for removing the moisture contained in prepreg tape.
  • Resistance welding of carbon fiber reinforced thermoplastic composites using spread carbon fiber heating element, D. Tanabe, F. Kubohori, K. Nishiyabu, T. Kurashiki, ECCM 2016 - Proceeding of the 17th European Conference on Composite Materials,   2016 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85018608851&origin=inward
    Summary:© 2016, European Conference on Composite Materials, ECCM. All rights reserved. This study aims to develop the resistance welding method for continuous fiber reinforced thermoplastic (cFRTP) composites using spread carbon fiber as resistance heating element. The material for the experiment was woven CF/PPS laminates. The effects of processing conditions such as applied voltage, time and pressure, and also material conditions such as thickness of the inserted PPS films on the fusion behavior of cFRTP composites were investigated to get the optimum condition for electro-fusion joining. The contents for evaluation were surface condition of joint section peeled off after applying current and welding area obtained from those images. The experimental results revealed that electro-fusion behavior was influenced significantly by thickness of PPS films and electric resistivity of cFRTP laminates. From the result of the single lap shear strength (LSS) test,it was revealed that the LSS value was achieved over 28 MPa.
  • Effects of heating conditions on high frequency induction welding behavior of carbon fiber reinforced thermoplastic composites, D. Tanabe, K. Kurauchi, Y. Kawamura, K. Nishiyabu, T. Kurashiki, ECCM 2016 - Proceeding of the 17th European Conference on Composite Materials,   2016 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85018583480&origin=inward
    Summary:© 2016, European Conference on Composite Materials, ECCM. All rights reserved. This study aims to develop the high frequency induction welding process for continuous carbon fiber reinforced thermoplastics (CFRTP). The materials used for experiment were unidirectional CF/PPS (UD-CF/PPS [0]6 and UD-CF/PPS [0/90]3), woven-CF/PPS and woven-CF/PA66. The induction coil used was pancake type coil.The effects of heating conditions such as the coil height, induction heating power, coil-roller distance were investigated in order to predict the optimum processing conditions. From the some induction heating experiment results, it was found that UD-CF/PPS [0]6 laminate was not suited for induction heating, because the electric circuit was hardly formed in the laminate. On the other hand, UD-CF/PPS [0/90]3 and woven laminates were better heated. From the result of single lap shear strength test, the strength was increased with decreasing the coil - roller distance.
  • 熱可塑性CFRPにおける金型・成形技術の開発動向 研究事例 3 熱可塑性CFRPの量産・再利用のための型技術, NISHIYABU KAZUAKI, TANABE DAIKI, 型技術, 30, 5, 032, 036,   2015 05 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201502208928085040
  • Effects of processing conditions in unidirectional carbon fiber thermoplastic tape laying, D. Tanabe, K. Nishiyabu, T. Kurashiki, ICCM International Conferences on Composite Materials, 2015-July,   2015 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85018568696&origin=inward
    Summary:© 2015 International Committee on Composite Materials. All rights reserved. Automated thermoplastic tape laying (ATL) and automated fiber placement (AFP) are high-potential manufacturing methods for continuous fiber reinforced thermoplastic composites which can ensure operational safety even in highly loaded components such as aircraft wing skins and fuselages or construction large scaled structures. These methods often use computer-controlled robotics to lay one or several layers of carbon fiber thermoplastic tape or tows onto a mold, and should be optimized some processing parameters such as heating, pressing and feed speed and so on. Though the final aim of this study is to manufacture composite laminates made from tapes pre-impregnated with unidirectional carbon fiber reinforcement and a thermoplastic matrix, this study focuses on thermal distribution and interlaminar bond strength in a laying process of unidirectional carbon fiber reinforced thermoplastic tape. The tape are commonly heated up to the melting temperature by various heating sources including heated roller, hot gas torch, near-infrared light lump, induction coil and high powder diode laser and so on. A near-infrared heater has some advantages such as rapid start-up speed, suitable for heating of carbon fiber and low cost. However, the heating characteristic is deeply influenced by position of the heater and feed rate of prepreg tape, thus it is necessary to optimize these heating parameters. On the other hand, the crystallinity of thermoplastic polymers is directly affected by cooling rate, and the bonding strength between prepreg tapes is depended on the degree of crystallization. Therefore, it is important for the thermoplastic prepreg tape laying process to investigate the cooling and consolidation behavior. This study aimed to predict the optimum processing condition for thermoplastic tape laying. The material used for the experiment was unidirectional carbon fiber reinforced polyamide 6 prepreg tape. The effects of processing conditions such as number and position of infrared heaters, feed speed of tape, temperature and pressure of compaction roller on the laying behavior of prepreg tape were investigated. The temperature distribution on the prepreg tape obtained by infrared thermometer and thermocouple measurement and the interlaminar shear strength of tapes are correlated as concluding remarks of this study.
  • Fabrication of ES-nanofiber imprinting plastic mold and micro-structured parts by nanopowder printing, Kazuaki Nishiyabu, ICCM International Conferences on Composite Materials, 2015-July,   2015 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85053141577&origin=inward
    Summary:© 2015 International Committee on Composite Materials. All rights reserved. This study aims to develop the eco-friendly fabrication method for micro-structured parts with high aspect ratio. To achieve this purpose, nanopowder printing (nPP) process was adopted to the plastic mold with microscopic textures prepared by electrospinning nanofiber imprinting (ES-NFI) method. The novel method named as ES-NFI sacrificial plastic mold nanopowder printing (ES-NFI/nPP) was proposed and demonstrated in this study. ES-NFI method was applied to Si form that have several patterns including line-space, multi pillars and multi holes with various micro-structured sizes, thus plastic molds with finer microscopic textures were prepared for nPP process. The nanofiber was produced by electro-spinning (ES) process which provides a simple and versatile method for generating ultrathin fibers using variety of materials. The ES condition on the diameter of nanofiber was optimized to generate ultrafine fiber steady. By melting ES-nanofiber coated on Si forms, the plastic molds with the microscopic textures were replicated properly by polymethylmethacrylate (PMMA) polymer. The effect of aspect ratio in microstructures on the shape transcription was investigated by changing the size of microscopic texture of Si form from 1μm to 50μm wide for 10μm high. The experimental result shown that the microstructures with 1μm wide to 10μm high could be formed precisely on the surface of plastic mold after melting ES-nanofiber with approx. 100nm in mean diameter. Then it was confirmed that the ES-NFI method proposed in this study was superior for fabricating the plastic mold with finer microstructures and it was preferable in comparing with a conventional dipping method. This conclusion does not only attribute a good transcription to finer fiber, but it is considered to be obtained by in-situ extraction of solvent during ES process. Also the composition of paste materials made from TiO2 nano-sized powder and PEG water-soluble binder was varied for the optimization. It was shown from the experimental results that the sintered parts with microstructures of 50μm wide for 10μm high could be formed soundly, and it was also desirable to use the paste materials with lower content of binding polymer in keeping adequate viscosity. It was concluded that ES-NFI/nPP method was a useful method for fabricating the micro-structured parts in the mass production.
  • Fabrication of micro-structured parts by nanopowder printing using ES-nanofiber imprinting plastic mold, NISHIYABU Kazuaki, KAWAKAMI Jiro, Transactions of the JSME (in Japanese), 81, 829, 14, 00604-14-00604,   2015 , 10.1299/transjsme.14-00604, http://ci.nii.ac.jp/naid/130005100334
    Summary:This study aims to develop an eco-friendly fabrication method for micro-structured parts with high aspect ratio. To achieve this purpose, nanopowder printing (nPP) process was adopted to the plastic mold with microstructures produced by electrospinning nanofiber imprinting (ES-NFI) method. A novel method named as ES-NFI sacrificial plastic mold nanopowder printing (ES-NFI/nPP) was proposed and demonstrated in this study. Micro plastic molds were prepared by ES-NFI method using Si forms that have various micro-structures including line and space (L/S) pattern, multi-pillars and holes. The effects of aspect ratio in microstructure on the shape transcription were investigated by changing Si forms from 1µm to 50µm wide for 10µm high. Also the composition of paste materials made from TiO<sub>2</sub> nano-sized powder and PEG water-soluble binder was varied for the optimization. It was shown from the experimental results that the sintered part with microstructures of 50µm wide for 10µm high could be formed soundly, and it was also desirable to use the paste materials with lower content of binder polymer in keeping adequate viscosity. It was confirmed that ES-NFI/nPP method was a useful method for fabricating the micro-structured parts in the mass production.
  • Fabrication of micro-structured parts by nanopowder printing using ES-nanofiber imprinting plastic mold, NISHIYABU Kazuaki, KAWAKAMI Jiro, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 0, 0,   2015 , 10.1299/transjsme.14-00604, http://ci.nii.ac.jp/naid/130005094452
    Summary:This study aims to develop an eco-friendly fabrication method for micro-structured parts with high aspect ratio. To achieve this purpose, nanopowder printing (nPP) process was adopted to the plastic mold with microstructures produced by electrospinning nanofiber imprinting (ES-NFI) method. A novel method named as ES-NFI sacrificial plastic mold nanopowder printing (ES-NFI/nPP) was proposed and demonstrated in this study. Micro plastic molds were prepared by ES-NFI method using Si forms that have various micro-structures including line and space (L/S) pattern, multi-pillars and holes. The effects of aspect ratio in microstructure on the shape transcription were investigated by changing Si forms from 1µm to 50µm wide for 10µm high. Also the composition of paste materials made from TiO2 nano-sized powder and PEG water-soluble binder was varied for the optimization. It was shown from the experimental results that the sintered part with microstructures of 50µm wide for 10µm high could be formed soundly, and it was also desirable to use the paste materials with lower content of binder polymer in keeping adequate viscosity. It was confirmed that ES-NFI/nPP method was a useful method for fabricating the micro-structured parts in the mass production.
  • Effects of processing parameters on electro-fusion joining of CF/PPS composites using carbon fiber heating elements, TANABE Daiki, NISHIYABU Kazuaki, KURASHIKI Tetsusei, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 81, 826, 15, 00005-15-00005,   2015 , 10.1299/transjsme.15-00005, http://ci.nii.ac.jp/naid/130005084367
    Summary:This study aims to develop the electro-fusion joining method for continuous fiber reinforced thermoplastic (cFRTP) composites using various carbon fibers as a resistance heating element. The material used for the experiment was woven CF/PPS laminates. The effects of processing conditions such as applied voltage, time and current and also material conditions such as thickness of the inserted PPS films on the fusion behavior of cFRTP composites were investigated. The optimum condition for electro-fusion joining were obtained from experimental results such as surface condition of joint section peeled off after applying current and welding area obtained from those images. The electro-fusion mechanism was revealed by investigating the electro-fusion condition such as applied voltage, conducting time and thickness of PPS films. The welding area was increased with increasing the applied voltage and the conducting time. It was revealed that there was optimum applied voltage and conducting time in order to prevent the thermal deformation and thermal degradation of CF/PPS laminates. It was also revealed that the uniform welding area was obtained by inserting the PPS film with the optimum thickness. When the fusion joining was carried out at the current control, the conducting behavior became stable compared to the voltage control. The results of single lap tensile strength tests revealed that the LSS value was more than 28MPa. When the spread carbon fiber 0° was used as heating element, the joining layer was reinforced with carbon fiber to the load direction.
  • Effects of processing parameters on electro-fusion joining of CF/PPS composites using carbon fiber heating elements, TANABE Daiki, NISHIYABU Kazuaki, KURASHIKI Tetsusei, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 0, 0,   2015 , 10.1299/transjsme.15-00005, http://ci.nii.ac.jp/naid/130005073776
    Summary:This study aims to develop the electro-fusion joining method for continuous fiber reinforced thermoplastic (cFRTP) composites using various carbon fibers as a resistance heating element. The material used for the experiment was woven CF/PPS laminates. The effects of processing conditions such as applied voltage, time and current and also material conditions such as thickness of the inserted PPS films on the fusion behavior of cFRTP composites were investigated. The optimum condition for electro-fusion joining were obtained from experimental results such as surface condition of joint section peeled off after applying current and welding area obtained from those images. The electro-fusion mechanism was revealed by investigating the electro-fusion condition such as applied voltage, conducting time and thickness of PPS films. The welding area was increased with increasing the applied voltage and the conducting time. It was revealed that there was optimum applied voltage and conducting time in order to prevent the thermal deformation and thermal degradation of CF/PPS laminates. It was also revealed that the uniform welding area was obtained by inserting the PPS film with the optimum thickness. When the fusion joining was carried out at the current control, the conducting behavior became stable compared to the voltage control. The results of single lap tensile strength tests revealed that the LSS value was more than 28MPa. When the spread carbon fiber 0° was used as heating element, the joining layer was reinforced with carbon fiber to the load direction.
  • Replication of micro-structured imprint plastic mold via electro-spinning nanofiber process, NISHIYABU Kazuaki, KAWAKAMI Jiro, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 81, 824, 14, 00571-14-00571,   2015 , 10.1299/transjsme.14-00571, http://ci.nii.ac.jp/naid/130005066579
    Summary:This study describes a novel method for fabricating the plastic mold with microstructure by nanofiber imprinting (NFI) into Si form. The nanofiber was produced by electro-spinning (ES) process which provides a simple and versatile method for generating ultrathin fibers using variety of materials. The effects of ES condition on the diameter of nanofiber were investigated for optimizing to generate ultrafine fiber. By melting ES-nanofiber coated on Si forms that have various micro-structures including line and space pattern, multi-pillars and holes, the plastic molds with those micro-structures were replicated for polymethylmethacrylate (PMMA) polymer. The effect of aspect ratio in microstructure on the shape transcription was investigated by changing Si form from 1μm to 50μm in width for 10μm in height. The usefulness of ES-NFI method proposed in this study was also investigated by comparing with a conventional dipping method. The experimental result shown that the microstructures with 1μm wide to 10μm high could be formed precisely on the surface of plastic mold after melting ES-nanofiber with approx 100nm in mean diameter. It was shown that ES-NFI method was superior for fabricating the plastic mold with finer microstructures. This conclusion does not only attribute a good transcription to finer fiber, but it is considered to be obtained by in-situ extraction of solvent during ES process.
  • Replication of micro-structured imprint plastic mold via electro-spinning nanofiber process, NISHIYABU Kazuaki, KAWAKAMI Jiro, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 0, 0,   2015 , 10.1299/transjsme.14-00571, http://ci.nii.ac.jp/naid/130005005166
    Summary:This study describes a novel method for fabricating the plastic mold with microstructure by nanofiber imprinting (NFI) into Si form. The nanofiber was produced by electro-spinning (ES) process which provides a simple and versatile method for generating ultrathin fibers using variety of materials. The effects of ES condition on the diameter of nanofiber were investigated for optimizing to generate ultrafine fiber. By melting ES-nanofiber coated on Si forms that have various micro-structures including line and space pattern, multi-pillars and holes, the plastic molds with those micro-structures were replicated for polymethylmethacrylate (PMMA) polymer. The effect of aspect ratio in microstructure on the shape transcription was investigated by changing Si form from 1μm to 50μm in width for 10μm in height. The usefulness of ES-NFI method proposed in this study was also investigated by comparing with a conventional dipping method. The experimental result shown that the microstructures with 1μm wide to 10μm high could be formed precisely on the surface of plastic mold after melting ES-nanofiber with approx 100nm in mean diameter. It was shown that ES-NFI method was superior for fabricating the plastic mold with finer microstructures. This conclusion does not only attribute a good transcription to finer fiber, but it is considered to be obtained by in-situ extraction of solvent during ES process.
  • フェムト秒レーザーによる微細周期構造のナノインプリント法への応用, OTSUKA MASATAKA, SOMEKAWA TOSHIHIRO, KAWAKAMI JIRO, NISHIYABU KAZUAKI, MAEDA YOSHINOBU, MATSUTANI TAKAOMI, FUJITA MASAYUKI, MIYANAGA NORIAKI, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, ROMBUNNO.17A-S9-5,   2014 09 01 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402211151647335
  • グリーンマシニングと焼結接合による製造した金属粉末射出成形品の形状評価, SAKURAI SHIN'YA, NISHIYABU KAZUAKI, TANAKA SHIGEO, 精密工学会関西地方定期学術講演会講演論文集, 2014, 50, 51,   2014 07 04 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402248461436483
  • Optimum parameters on electro fusion joining of CF/PPS composites by carbon fiber heating elements, D. Tanabe, K. Nishiyabu, T. Kurashiki, Proceedings of the American Society for Composites - 29th Technical Conference, ASC 2014; 16th US-Japan Conference on Composite Materials; ASTM-D30 Meeting,   2014 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84922149356&origin=inward
    Summary:Continuous fiber reinforced thermoplastic (cFRTP) composites which can be manufactured with press-forming are attracting attention recently in aircraft and automobile applications. However, cFRTP components have rather simple geometry due to the limited deformation allowed for the reinforcing fibers and high viscosity of the resin, and thus joining is required as an indispensable step in the manufacturing process of cFRTP. Conventional joining methods used for thermosetting composites such as mechanically fastening and adhesive bonding are unreasonable of applying for cFRTP components, because those methods have some drawbacks in strength and reliability, such as stress concentration and interlayer delamination. To solve the above-mentioned problems, the joining technologies such as ultrasonic welding, electro fusion joining and induction welding have been proposed for high performance cFRTP. In case of an electro-fusion joining method, a heating element such as a stainless steel mesh and Ni-Cr wires is required for fusion joining. However, these heating elements are undesirable materials which has some disadvantages on recyclability, stress concentration and corrosion because the metallic heating elements remains between joining parts. This study aims to develop an electro-fusion joining method for cFRTP. The heating element was used spread carbon fiber sheets instead of metallic wire or mesh. The material used for the experiment was woven CF/PPS laminate. The effects of processing conditions such as applied voltage, current and time, and also material conditions on the fusion behavior of cFRTP composites were investigated to get the optimum condition for electro-fusion joining. From the results of the single lap shear strength (LSS) test, the LSS of specimens joined using spread carbon fiber sheet was achieved over 28 MPa, which is 42% higher compared to that of the specimens joined using the metallic heating element.
  • Dimensional change of complex shape MIM parts fabricated by green machining and sintered joining, Shinya Sakurai, Kazuaki Nishiyabu, Shigeo Tanaka, Euro PM 2014 Congress and Exhibition, Proceedings,   2014 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84959058853&origin=inward
    Summary:This study aims to develop a trial production method for providing the complex-shaped MIM parts speedy at lower cost. The machining of green compacts and sintered joining were applied into MIM process. This study focuses on the shape and dimensional change between the machined green compacts and sintered parts in addition to the effect of sintered joining. The shape measurement of the green compacts and sintered parts was performed by the high accuracy 3D digitizer inspection system. Thus it was concluded from the experimental result that this proposed method was useful to produce many kinds of small-lot MIM parts, but the shape deformation in sintering of the joined green compacts should be adequately controlled.
  • Electro fusion joining of carbon fiber reinforced thermoplastic composites using carbon fiber heating element, D. Tanabe, K. Nishiyabu, T. Kurashiki, 16th European Conference on Composite Materials, ECCM 2014,   2014 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84915821709&origin=inward
    Summary:This study aims to develop the electro-fusion joining method for continuous fiber reinforced thermoplastic (cFRTP) composites using spread carbon fiber as resistance heating element. The material for the experiment was woven CF/PPS laminates. The effects of processing conditions such as applied voltage, time and pressure, and also material conditions such as thickness of the inserted PPS films on the fusion behavior of cFRTP composites were investigated to get the optimum condition for electro-fusion joining. The contents for evaluation were surface condition of joint section peeled off after applying current and welding area obtained from those images. The experimental results revealed that electro-fusion behavior was influenced significantly by thickness of PPS films and electric resistivity of cFRTP laminates. As the result of the single lap shear strength (LSS) test, the LSS value was achieved over 27 MPa.
  • 半導体レーザによる熱可塑性CFRPの融着挙動に関する評価, YAMAKAWA MASAFUMI, NAKAMOTO TSUYOSHI, TANABE DAIKI, NISHIYABU KAZUAKI, 複合材料シンポジウム講演要旨集, 39th, 173, 174,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402216911650910
  • Effects of Fiber Reinforcing Configuration on Oxidation and Melting Phenomenon of CF/PPS Laminated Composites by Electrically-Conducting, TANABE DAIKI, NISHIYABU KAZUAKI, KURASHIKI TETSUSEI, 材料, 63, 5, 368-373 (J-STAGE), 373,   2014 01 01 , 10.2472/jsms.63.368, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402297406497784
    Summary:This study aims to reveal the mechanism of melting and oxidation phenomenon of CF/PPS laminated composites by electrically-conducting. The materials used are unidirectional CF/PPS and woven CF/PPS laminates. The effects of applied voltage, conducting time and fiber reinforcing configuration on melting behavior of CFRTP composites were investigated. The melting state was evaluated by microscopic observation and its image analysis. The experimental results revealed that the melting and oxidation behavior were influenced by reinforcing configuration and electric resistivity of CFRTP laminates. The melting area of both CFRTP laminates tends to increase with increasing the applied voltage and conducting time. It was found that the insertion of PPS films in melting interface was required in order to prevent the edge effect and non-uniform profile shapes of the melting area. It was also confirmed that woven CF/PPS laminates could be melted at low applied voltage. © 2014 The Society of Materials Science, Japan.
  • Electro-fusion behavior of CF/PPS laminates using Ni-Cr wire resistance heating element, TANABE Daiki, NISHIYABU Kazuaki, KURASHIKI Tetsusei, TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, 80, 815, 189, SMM0189,   2014 , 10.1299/transjsme.2014smm0189, http://ci.nii.ac.jp/naid/130005004927
    Summary:This study aims to reveal the mechanism of electro-fusion joining of CFRTP composites using multiple Ni-Cr wires as resistance heating element. The materials used for electro-fusion joining test are unidirectional CF/PPS and woven CF/PPS laminates. The effects of electro-fusion condition such as applied voltage and fusion time, Ni-Cr wire spacing and PPS film thickness on the fusion behavior of CFRTP composites were investigated experimentally. The welding area and the joining strength were evaluated quantitatively by microscopic observation and single lap shear test. From the results of surface observation, it was shown that the welding area increased with increasing the applied voltage and fusion time, but thermal degradation and deformation were caused by excess conducting. It was also revealed that Ni-Cr wire spacing and PPS film thickness were significant parameters affecting on welding area and thermal degradation. The optimum electro-fusion condition could be obtained respectively for unidirectional CF/PPS and woven CF/PPS laminates because microscopic electro-fusion behavior was influenced by the fiber reinforcement configuration. Though the interlaminar shear strength (ILSS) is resulted in a marked improvement in the optimum electro-fusion conditions, ILSS was decreased significantly by inserting PPS film which can reduce the thermal degradation. Therefore the experimental results suggested that it is essential to avoid the thermal degradation of matrix polymer by heating of Ni-Cr wire.
  • 通電加熱による形状記憶合金ワイヤ/熱可塑性CFRPハイブリッド積層板の変形挙動, 田邉大貴, 石丸拓弥, 倉敷哲生, 西籔和明, 日本複合材料合同会議(CD-ROM), 5th, ROMBUNNO.3C-08,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402254428514517
  • 熱可塑性CFRP積層板の電気式融着における炭素繊維発熱体の形態と融着条件の影響, 田邉大貴, 森脇悠介, 西籔和明, 倉敷哲生, 日本複合材料合同会議(CD-ROM), 5th, ROMBUNNO.2C-07,   2014 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402286345772165
  • Effects of Processing Parameters on Electro-fusion Joining of CF/PPS Composites using Carbon Fiber Heating Elements, 田邉 大貴, 森脇 悠介, 西籔 和明, 機械材料・材料加工技術講演会 M&P, 21,   2013 11 08 , http://ci.nii.ac.jp/naid/40020159205
  • J045064 Thermal Deformation Behavior of Shape Memory Alloy Wire / Carbon Fiber Reinforced Thermoplastic Composites, ISHIMARU Takuya, TANABE Daiki, NISHIYABU Kazuaki, The Proceedings of Mechanical Engineering Congress, Japan, 2013, 0, _J045064, 1-_J045064-5,   2013 , http://ci.nii.ac.jp/naid/110009934742
    Summary:In this study, shape memory alloy (SMA) wires which were thermally-treated in a desired shape were embedded in the unidirectional carbon fiber reinforced thermoplastic (CFRTP) laminates aiming to utilize actively the anisotropic property of CFRTP as the active thermal actuator. The deformation behavior of the SMA/CFRTP laminate subjected to thermal load was investigated. The temperature is a significant parameter because the elastic property of SMA/CFRTP depends on the shape memory temperature of SMA wires and glass transition temperature of thermoplastic matrix. In this experiment, SMA/CFRTP laminates were fabricated with a hot press molding using unidirectional carbon fiber /PA6 (CF/PA6) prepreg sheets, PA6 films and Ni-Ti wires. The effects of placements of SMA wires and laminated sequences of SMA/CFRTP laminates on the deformation behavior of these laminates under the elevated temperature were investigated with the digital 3D strain field measurement.
  • J046013 Fusion Bonding of Carbon Fiber Reinforced Thermoplastic Composites by Electrofusion method, TANABE Daiki, MORIWAKI Yusuke, NISHIYABU Kazuaki, KURASHIKI Tetsusei, The Proceedings of Mechanical Engineering Congress, Japan, 2013, 0, _J046013, 1-_J046013-5,   2013 , http://ci.nii.ac.jp/naid/110009934760
    Summary:This study aims to reveal the mechanism of electro-fusion joining of CFRTP composites using carbon fiber filament as resistance heating element. The material used is woven CF/PPS laminates. The effects of applied voltage, fusion time and thickness of inserted PPS films on fusion behavior of CFRTP composites in electro-fusion welding were investigated. The welding area and fusion shape were evaluated by microscopic observation and its image analysis. The experimental results revealed that electro-fusion behavior is influenced by thickness of inserted PPS films and electric resistivity of CFRTP laminates. From the welding area calculated by image analysis, it is obvious that the welding area of CFRTP laminates tends to increase with increasing the applied voltage and fusion time. It was also confirmed that woven CF/PPS laminates could be welded at low applied voltage and long times.
  • J112011 Fabrication of Micro-structured Imprint Plastic Mold via ES-nanofiber Process, SAKURAI Shinya, KAWAKAMI Jiro, NISHIYABU Kazuaki, The Proceedings of Mechanical Engineering Congress, Japan, 2013, 0, _J112011, 1-_J112011-5,   2013 , http://ci.nii.ac.jp/naid/110009935381
    Summary:This study describes the new fabrication method of micro plastic mold imprinted nanofiber produced by electro-spinning (ES) process which provides a simple and versatile method for generating ultrathin fibers using variety of materials. The plastic mold aims to use for printing the micro-structured part using nano-powder based paste. The plastic molds that have various micro-structures including line and space patterns, multi-pillars and holes were prepared using polymethy lmethacrylate (PMMA) polymer. The experimental result shown that microstructures with 1μm wide to 50nm high and 10μm high could be formed precisely on the surface of plastic mold after melting ES-nanofibers.
  • 113 Effects of Processing Parameters on Electro-fusion Joining of CF/PPS Composites using Carbon Fiber Heating Elements, TANABE Daiki, MORIWAKI Yusuke, NISHIYABU Kazuaki, KURASHIKI Tetsusei, The Proceedings of the Materials and processing conference, 2013, 0, _113, 1_-_113-5_,   2013 , http://ci.nii.ac.jp/naid/110009935800
  • J046031 Evaluation on Thermal Deformation Behavior of AI/Thermoplastic CFRP Hybrid laminates, MORISUGI Tetsuya, MATSUKURA Takuya, NISHIYABU Kazuaki, The Proceedings of Mechanical Engineering Congress, Japan, 2013, 0, _J046031, 1-_J046031-5,   2013 , http://ci.nii.ac.jp/naid/110009935217
    Summary:Carbon fiber reinforced thermoplastic (CFRTP) has some excellent properties such as high productivity, high fracture toughness and high recyclability compared to the thermosetting plastic (CFRTS). Unidirectional CFRTP behaves highly anisotropy in elastic modules and strength depending on the fiber orientation angle. It is also desired to take advantage of the potential for anisotropic properties in the structural design of composites. On the other hand, thermoplastics are affected remarkably by service temperature because of the low glass-transition temperature, and the elastic modulus of thermoplastics changes near the glass-transition and melting temperatures. This study aims to investigate thermal deformation behavior of hybrid laminated composites which were prepared with various laminated constitutions of A1 sheet and unidirectional CF/PA6 prepreg sheet. The shape deformation was evaluated using non-contact 3D strain field measuring instrument based on digital image correlation method (DIC). It was clarified from the experimental result that curvature of hybrid laminates decreased almost linearly with increasing the temperature.
  • Effects of processing parameters on electro-fusion joining behavior of CF/PPS composites, D. Tanabe, S. Tsutaya, K. Nishiyabu, T. Kurashiki, ICCM International Conferences on Composite Materials, 2013-July, 3722, 3731,   2013 01 01 , https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85053217769&origin=inward
  • J046014 Punching Behavior of Carbon Fiber Reinforced Thermoplastic Laminated Composites, NAKANISHI Keita, NISHIYABU Kazuaki, The Proceedings of Mechanical Engineering Congress, Japan, 2013, 0, _J046014, 1-_J046014-5,   2013 , http://ci.nii.ac.jp/naid/110009934761
    Summary:This study describes the punching behavior of woven carbon fiber reinforced thermoplastic composites. The matrix polymer used is Polyamide 66 (PA66) resin. A circular hole is machined by two types of punch with different tool profiles such as flat edge and wave edge. Load applied at punch which was pushed to laminates with a small servo-pressing unit were measured. The quality of machining was examined by a digital microscope observation of cross-section near hole. It was found that the applied load reduced with increasing the temperature of specimen and working speed of punch. It was also recognized that wave edge tool became lower the applied load than flat edge one.
  • S041011 Fabrication of Micro-structured Parts by Nano-powder Printing using ES-nanofiber Imprinting Mold, SAKURAI Shinya, KAWAKAMI Jiro, NISHIYABU Kazuaki, The Proceedings of Mechanical Engineering Congress, Japan, 2013, 0, _S041011, 1-_S041011-5,   2013 , http://ci.nii.ac.jp/naid/110009933986
    Summary:This study aims to fabricate the micro-structured parts using nano-powder via compaction process by printing.The sacrificial plastic mold(SP-mold) which is derived from melting nanofiber produced by electron spinning(ES) method which provides a simple and versatile method for generating ultrathin fibers using variety of materials is used.The original form made of silicon has micro-sized structures with line and space patterns.The material used for printing is the mixture of nano-scale Ti0_2 powder and water-soluble binder.It was shown from the results of surface observation that the SP-mold could be obtained finely,while the green compact and sintered part has significant deformation and cracks due to the low density of powder compaction in printing step.
  • Deformation behavior of shape-memory alloy wire/carbon fiber reinforced thermoplastic composites, Y. Tabuchi, T. Morisugi, D. Tanabe, K. Nishiyabu, 8th Asian-Australasian Conference on Composite Materials 2012, ACCM 2012 - Composites: Enabling Tomorrow's Industry Today, 2, 1473, 1478,   2012 12 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84892977121&origin=inward
    Summary:In this study, shape-memory alloy (SMA) wires which were thermally-treated in a desired shape were embedded in the unidirectional carbon fiber reinforced thermoplastic (CFRTP) composites aiming to utilize actively the anisotropic property of CFRTP as the active thermal actuator. The deformation behavior of the SMA/CFRTP laminate subjected to thermal load was investigated. The temperature is a significant parameter because the deformation of SMA/CFRTP changes by the shape memory temperature of SMA wires and glass transition temperature of thermoplastic matrix polymer. In this experiment, SMA/CFRTP laminates were fabiracatged with a hot press molding using unidirectional carbon fiber/polyamide-6 (CF/PA6) semi-prepreg sheet and Ni-Ti wires. The effects of placements of SMA wires and laminated sequences of SMA/CFRTP laminates on the deformation behavior of the laminates under the elevated temperature were investigated with non-contact strain field measurement. Copyright © (2012) Asian-Australasian Association for Composite Materials (AACM).
  • Fusion behavior of continuous fiber reinforced thermoplastic composites in electro-fusion welding, D. Tanabe, S. Tsutaya, K. Nishiyabu, T. Kurashiki, 8th Asian-Australasian Conference on Composite Materials 2012, ACCM 2012 - Composites: Enabling Tomorrow's Industry Today, 2, 1560, 1565,   2012 12 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84893003390&origin=inward
    Summary:This study aims to reveal the mechanism of electro-fusion joining of continuous fiber reinforced thermoplastic (cFRTP) composites. The materials used are unidirectional CF/PPS and woven CF/PPS laminates. The effects of applied voltage, holding time and fiber reinforcing configuration on fusion behavior of cFRTP composites in electro-fusion welding were investigated. The fusion area and fusion shape were evaluated by microscopic observation and its image analysis. The experimental results revealed that the fusion area tends to increase with increasing the applied voltage and holding time in both unidirectional and woven CF/PPS laminates, but woven CF/PPS laminates can be welded at lower applied voltage. It is concluded that the electro-fusion behavior is affected significantly by reinforcing configuration and electric resistivity of cFRTP composites. Copyright © (2012) Asian-Australasian Association for Composite Materials (AACM).
  • Powder space holder metal injection molding (PSH-MIM) of micro-porous metals, K. Nishiyabu, Handbook of Metal Injection Molding, 349, 390,   2012 06 11 , 10.1533/9780857096234.3.349, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84896784829&origin=inward
    Summary:© Woodhead Publishing Limited, 2012. All rights reserved. This chapter describes the metal injection molding (MIM) process for manufacturing metal components with micro-sized porous structures. The process has been achieved by applying the powder space holder (PSH) method to the MIM process. The novel PSH-MIM process is capable of net-shape manufacturing precise micro-porous metal parts by controlling pore size and porosity. This chapter also includes detailed explanations of the pore formation mechanism and optimum material selection, as well as describing examples of micro-porous MIM parts and their properties.
  • Deformation analysis of complex shaped Ti-MIM parts by digital image measurement, Kazuaki Nishiyabu, Kenji Okubo, Shigeo Tanaka, Proceedings of the International Euro Powder Metallurgy Congress and Exhibition, Euro PM 2012, 3,   2012 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84902337820&origin=inward
    Summary:This study aims to demonstrate the usefulness of digital image measurement for the optimization of manufacturing condition and the quality management of MIM parts. New types of measuring systems were used to measure the 3D coordinate and strain field of Ti-MIM parts with very complex shape. Debinding and sintering were carried out under three types of setting conditions: 1) laying and 2) standing on Al2O3 plate, and 3) embedding in Al2O3 powder. The effects of the setting condition on the shape of sintered parts could be clarified quantitatively and visually by the digital image measurement. Also the difference in shape between the measured data of sintered parts and the 3D-CAD data could be visualized, and less-visible flaw mark could be detected easily. Thus it is concluded that the digital image measurement has a great potential to inspect precisely the shape error and strain field of complex shaped MIM parts under loading.
  • Filling behaviour and magnetic properties of Fe-45Ni Permalloy micro-MIM parts, Kazuaki Nishiyabu, Kenji Okubo, Shigeo Tanaka, Proceedings of the International Euro Powder Metallurgy Congress and Exhibition, Euro PM 2012, 3,   2012 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84902350004&origin=inward
    Summary:This study aims to manufacture the micro-MIM parts exhibiting excellent soft magnetic properties. The effects of solid loading of feedstock and injection speed on the sintered density and the coercivity were investigated. The feedstock composed of Fe-47Ni powder and binders was prepared by changing the solid loading of 60-67% and were injection-moulded into micro-dumbbell specimen with 0.16mm in parallel portion and 2.52mm in diameter of chucking parts. The internal mould pressure was measured in the chucking parts. The filling behaviour of feedstock into the micro- dumbbell specimen was investigated by comparing the results of flow simulation and short shot test, then the internal pressure drop and jetting phenomena were revealed. It could be concluded that the coercivity of the sintered parts was significantly influenced by the density reduction and the remaining carbon content, thus the solid loading of feedstock and injection speed in addition to debinding- sintering conditions should be optimized.
  • J164021 Preparation of Micro-structured Parts by ES-nanofiber Imprint Plastic Mold Insert MIM, NISHIYABU Kazuaki, Mohd Ikhwan, The Proceedings of Mechanical Engineering Congress, Japan, 2012, 0, _J164021, 1-_J164021-5,   2012 , http://ci.nii.ac.jp/naid/110009994990
    Summary:The micro-sacrificial plastic mold insert metal injection molding (μ-SPiMIM) process is useful to produce tiny metal parts including micro-sized and micro-structured parts. In this paper, the formation process of sacrificial plastic mold (SP-mold) is presented. This SP-mold is produced by electrospinning (ES) process which provides a simple and versatile method for generating ultrathin fibers using variety of materials. The SP-molds that have various micro-structures including line and space patterns, multi-pillars and holes were prepared using polymethylmethacrylate (PMMA) polymer. The experimental result shown that microstructure with 5μm wide and 10μm high could be formed on the surface of SP-mold after melting ES-nanofibers.
  • J043042 Fusion Behavior of Carbon Fiber Reinforced Thermoplastic Composites in Electro-fusion Welding, TANABE Daiki, TSUTAYA Shinji, NISHIYABU Kazuaki, KURASHIKI Tetsusei, The Proceedings of Mechanical Engineering Congress, Japan, 2012, 0, _J043042, 1-_J043042-5,   2012 , http://ci.nii.ac.jp/naid/110009994519
    Summary:This study aims to reveal the mechanism of electro-fusion joining of CFRTP composites. The materials used are unidirectional CF/PPS and woven CF/PPS laminates. The effects of applied voltage, holding time and fiber reinforcing configuration on fusion behavior of CFRTP composites in electro-fusion welding were investigated. The fusion area and fusion shape were evaluated by microscopic observation and its image analysis. The experimental results revealed that electro-fusion behavior is influenced by reinforcing configuration and electric resistivity of CFRTP laminates. From the fusion area calculated by image analysis, it is obvious that the fusion area of both CFRTP laminates tends to increase with increasing the applied voltage and holding time. It was also confirmed that woven CF/PPS laminates could be welded at low applied voltage.
  • J043021 Hot Press Molding and Deformation Behavior of Shape-Memory Alloy Wire / Carbon Fiber Reinforced Thermoplastic Composites, TABUCHI Yoshiaki, TANABE Daiki, NISHIYABU Kazuaki, KURASHIKI Tetsusei, The Proceedings of Mechanical Engineering Congress, Japan, 2012, 0, _J043021, 1-_J043021-5,   2012 , http://ci.nii.ac.jp/naid/110009994509
    Summary:In this study, shape memory alloy (SMA) wires which were thermally-treated in a desired shape were embedded in the unidirectional carbon fiber reinforced thermoplastic (CFRTP) laminates aiming to utilize actively the anisotropic property of CFRTP as the active thermal actuator. The deformation behavior of the SMA/CFRTP laminate subjected to thermal load was investigated. The temperature is a significant parameter because the elastic property of SMA/CFRTP depends on the shape memory temperature of SMA wires and glass transition temperature of thermoplastic matrix. In this experiment, SMA/CFRTP laminates were fabricated with a hot press molding using unidirectional carbon fiber / PA6 (CF/PA6) prepreg sheets, PA6 films and Ni-Ti wires. The effects of placements of SMA wires and laminated sequences of SMA/CFRTP laminates on the deformation behavior of these laminates under the elevated temperature were investigated with the digital 3D strain field measurement.
  • Report on "JSMS COMPOSITES Young Researcher Symposium, 2011", NISHIYABU Kazuaki, journal of the Japan Society for Testing Materials, 60, 12, 1156,   2011 12 01 , 10.2472/jsms.60.1156, http://ci.nii.ac.jp/naid/130002085186
  • Anisotropic behavior in bending deformation of CF/EPOXY and CF/PPS laminates under concentrated and thermal load, K. Nishiyabu, T. Yoshizawa, D. Tanabe, T. Kurashiki, ICCM International Conferences on Composite Materials,   2011 12 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84875928413&origin=inward
  • J043021Effects of Fiber Orientation Angle and Temperature Load on Bending Deformation of Woven Fabric Reinforced Thermoplastic Composites, YOSHIZAWA Takahiro, TANABE Daiki, NISHIYABU Kazuaki, KURASHIKI Tetsusei, Mechanical Engineering Congress, Japan, 2011, 0, "J043021, 1"-"J043021-4",   2011 09 11 , http://ci.nii.ac.jp/naid/110009759351
    Summary:In this study, the anisotropic behavior in bending deformation of woven carbon fabrics reinforced PPS thermoplastic laminated composites with various fiber orientation angles under a concentrated and thermal loading was mainly investigated by coordinate measurements. Two parameters for anisotropic evaluation of the bending deformation such as the amount of torsion and degree of anisotropy were used. The anisotropic behavior in bending deformation of woven fabric thermoplastic laminated composites under thermal load was affected strongly by matrix resin segregation on the surface of laminates. The matrix resin segregation arises especially at both ends of the wrap yarn direction on the uncut laminates result from roll forming processes. Also, the distribution of the matrix resin changes by the cutting out position of test specimens.
  • Processing of polymer-derived porous SiC body using allylhydridopolycarbosilane (AHPCS) and PMMA microbeads, KOTANI Masaki, NISHIYABU Kazuaki, MATSUZAKI Satoru, TANAKA Shigeo, Journal of the Ceramic Society of Japan, 119, 1391, 563, 569,   2011 07 01 , 10.2109/jcersj2.119.563, http://ci.nii.ac.jp/naid/130000784430
    Summary:A simple method for making a porous SiC body through a polymeric route at one firing processing was demonstrated by the sacrificial filler template approach. By incorporating sacrificial pore-forming plastic powder, PMMA microbeads, into liquid preceramic polymer, AHPCS, and losing it after the polymer was hardened, a preceramic porous body was formed. As a consequence of systematic examination of the effects of particle size and mixture ratio of the powder, an AHPCS-derived porous SiC body was reproducibly formed without critical crack initiation. It was enabled only when the polymer was sufficiently contained to make a strong skeletal structure with the sacrificial plastic particles closely distributed. The porous microstructure would contribute to efficient gas emission and uniform thermal shrinkage during polymer pyrolysis, which reduced internal pressure and crack-causing thermal stress.
  • Report on "JSMS COMPOSITES Young Researcher Symposium, 2010", KURASHIKI Tetsusei, NISHIYABU Kazuaki, journal of the Japan Society for Testing Materials, 60, 3, 273,   2011 03 01 , 10.2472/jsms.60.273, http://ci.nii.ac.jp/naid/130000673526
  • Diamond additions don't guarantee better heat sinks, NISHIYABU KAZUAKI, KANOKO YASUHIRO, TANABE DAIKI, TANAKA SHIGEO, Met Powder Rep, 66, 2, 27, 32,   2011 03 01 , 10.1016/S0026-0657(11)70060-1, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102283208788096
    Summary:As computers and other electronic devices become more powerful, they also generate more heat. Heat sinks are commonly used to dissipate this waste energy, but can they be made more efficient? Research sometimes gives mixed results... © 2011 Elsevier Ltd. All rights reserved.
  • Manufacturing of 316L stamper for imprinting by micro sacrificial plastic mould inserted MIM, Kenji Okubo, Shigeo Tanaka, Hiroshi Ito, Kazuaki Nishiyabu, Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2011, 2,   2011 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84902214866&origin=inward
    Summary:This study aims to develop the manufacturing method of metallic stamper for imprinting with micro structures by metal powder injection moulding (MIM). The mould used was prepared by imprinting plastic sheet. In the micro-sacrificial plastic mould insert MIM named as μ-SPiMIM process, the feedstock composed of stainless steel 316L (D50=2μm) or Ni (D50=0.74μm) powder and polyacetal-based binder was filled into polymethylmethacrylate mould with line and space patterns from 47μm wide, 150μm high to 6μm wide, 19μm high, and it was debinded and sintered in H2 and Ar gas atmosphere. The filling state of feedstock into micro-channels and transcriptional property in sintered parts was evaluated by cross-sectional SEM observation. The experimental results revealed reasonable evidences using submicron Ni powder could sinter at low temperature and accomplished high transcription in narrow cavity mould. It can be concluded that the μ-SPiMIM process has potential to mass-produce the stamper for imprinting made of versatile highly-durable metals.
  • Structural strength prediction for porous titanium based on micro-stress concentration by micro-CT image-based multiscale simulation, TAKANO NAOKI, FUKASAWA KEN, NISHIYABU KAZUAKI, Int J Mech Sci, 52, 2, 229, 235,   2010 02 01 , 10.1016/j.ijmecsci.2009.09.013, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002218114893046
    Summary:For the design of porous titanium component, differently from its use as functional materials, structural strength prediction algorithm is proposed based on the micro-stress concentration analyzed by the multiscale simulation. The modeling of real microstructure is carried out by the image-based technique with X-ray micro-CT. The multiscale computational method consists of asymptotic homogenization and finite element mesh superposition (FEMS) techniques. A criterion is proposed to predict the nonlinearity initiation point in the load and displacement curve by means of micro-stress distribution expressed by histogram. Only the constituent's yield strength is referred regardless of the microscopic morphology. The originality of this paper lies in the validation of the homogenization process, the modeling guideline of micro-mesh superposition onto macro-mesh in FEMS, and the strength prediction algorithm. L-shaped components with different pore diameter were discussed in both experiment and simulation. © 2009 Elsevier Ltd. All rights reserved.
  • Effect of micro/nano powder ratio on the properties of copper sintered parts produced by metal injection molding, Kazuaki Nishiyabu, Kenichi Kakishita, Shigeo Tanaka, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 76, 996, 1001,   2010 01 01 , 10.1299/kikaia.76.996, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=77957294979&origin=inward
    Summary:In microminiaturization of metal injection molding, the use of finer metal powders is one of solutions for improving the dimensional accuracy and surface roughness of sintered products. This study aims to investigate the effects of micro/nano powder ratio on the properties of sintered parts in μ-MIM process. A novel experimental machine which can achieve to mold without pelletizing was used to produce the tiny specimens with high trial efficiency and a small amount of feedstock. Small dumbbell specimens were produced with changing the binder content and the fraction of micro/nano copper powders. The effects of nano copper powder addition on the tap density of mixed powder, the viscosity of MIM feedstock and the grain size, surface roughness and tensile strength of sintered parts were revealed.
  • Fabrication of micro-structured parts by resist-film insert metal injection molding and effects of particle size, Kazuaki N. Nishiyabu, Kenichi Kakishta, Shigeo Shigeo, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 76, 75, 80,   2010 01 01 , 10.1299/kikaia.76.75, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=77950256936&origin=inward
    Summary:The manufacturing method of resist film insert metal powder injection molding (MIM) namely Resist/μ-SpiMIM process has been proposed. The resist film made of PMMA polymer with numerous micro-holes was used as micro sacrificial plastic mold (SP-mold). A novel molding machine which could achieve to mold without pelletizing was also used to produce the green compacts with a high efficiency in experiment by using a small amount of feedstock. The feedstock prepared by pure copper powders with various particle sizes was injection-molded into the SP-mold and the sintered parts with micro-pillar structure were produced after debinding and sintering process. The effects of particle size on density, shape-transcription and surface roughness of those sintered parts were discussed. The decreasing of particle size results in a marked improvements of surface roughness, transcription and dimensional variation of sintered parts.
  • Metal injection moulding process for copper/diamond composites with high thermal conductivity by using nanopowder, Kazuaki Nishiyabu, Yasuhiro Kanoko, Daiki Tanabe, Shigeo Tanaka, Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010, 4,   2010 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84902167539&origin=inward
    Summary:This study aims to develop the MIM process for manufacturing the micro heat sinks made of copper/diamond composites with high thermal conductivity. Diamond powder was added into the feedstock composed of copper powder and polyathetal-based binder. The compound feedstock was moulded into a sacrificial plastic mould (SP-mould), and the green compacts with micro-pillars were obtained and the SP-mould was removed by means of solvent extraction. The green compacts were then oxidized in air, followed by sintering in a reducing gas atmosphere. Nano-sized copper powder was used for drastically decreasing the sintering temperature to prevent from thermal damage on the surfaces of diamond particles. The sintered parts were also prepared by spark plasma sintering in contrast to conventional thermal furnace sintering, and they were evaluated by density and thermal conductivity measurements. The experimental results show that using nanopowder can give sufficiently high sintered density at low sintering temperature. However, the thermal conductivity of sinterd parts cannot reach the high values to be expected from the rule of mixture.
  • Micro metal injection moulding by NIL lost form technology and using nanopowder, Kazuaki Nishiyabu, Daiki Tanabe, Yasuhiro Kanoko, Shigeo Tanaka, Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010, 1,   2010 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84902213349&origin=inward
    Summary:This study aims to develop the manufacturing method of micro-structured parts by the metal powder injection moulding (MIM) inserted sacrificial plastic moulds which were prepared by thermal nanoimprint lithography (NIL). In this process named NIL/μ-SPiMIM, the feedstock composed of nano-sized copper powder and polyacetal-based binder adequately prepared was moulded into polymethylmethacrylate film with fine line and space pattern structures. After the film was removed by organic solvent, molded parts were debinded in vacuum and oxidized in atmosphere, followed by sintering in a reductive gas atmosphere. The filling of feedstock into micro-channels and debinding-sintering conditions were optimized. The microscopic transcriptional property in molded and sintered parts was evaluated by cross-sectional SEM observation. The experimental results revealed reasonable evidences using nanopowder could sinter at very low temperature with keeping the fine shapes. It can be concluded that the manufacturing method of NIL/μ-SPiMIM has great potential to produce precisely metallic parts with a single-digit micrometered structures.
  • Effect of Tension and Curvature of Skin on Insertion Characteristics of Microneedle Array, TACHIKAWA Hiroto, TAKANO Naoki, NISHIYABU Kazuaki, MIKI Norihisa, AMI Yoshimichi, Journal of Solid Mechanics and Materials Engineering, 4, 3, 470, 480,   2010 , 10.1299/jmmp.4.470, http://ci.nii.ac.jp/naid/130000255521
    Summary:Recent MEMS (micro electro mechanical system) fabrication techniques have made it possible to produce painless microneedles precisely enough to be inserted into epidermis layer penetrating the stratum corneum of human skin. This paper presents a testing procedure to evaluate the insertion characteristics of microneedle array using cultured human skin considering the tension and the curvature. First, the biaxial strain applied to the cultured human skin was measured by optical technique with image processing. It was found that almost constant strain could be successfully given within a certain area and that error factors in the experiment except the thickness variation of the cultured skin were negligible. Next, using a microneedle square array for brain machine interface (BMI) application, the effects of biaxial tension and the curvature on insertion characteristics were discussed. Within the above mentioned area with high strain, the needles were successfully inserted.
  • A case study on computational fluid dynamics analysis of Micro-MIM products, Andrews Ian, Nishiyabu Kazuaki, Tanaka Shigeo, Bulletin of Osaka Prefectural College of Technology, 43, 29, 40,   2009 12 28 , http://ci.nii.ac.jp/naid/120005352691
  • Manufacturing of micro-structured parts by LIGA sacrificial plastic mold insert metal injection molding, Kazuaki Nishiyabu, Yasuhiro Kanoko, Shigeo Tanaka, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 75, 1719, 1725,   2009 12 01 , 10.1299/kikaia.75.1719, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=77949422343&origin=inward
    Summary:The manufacturing method of micro sacrificial plastic mold (SP-mold) insert metal injection molding (MIM) combined LIGA process, namely LIGA/-SPiMIM process has been proposed to solve specific problems involving the miniaturization of MIM. Two types of SP-molds with fine structures were used : 1) PMMA resist, 2) PMMA mold injected into Ni-electroform, which is a typical LIGA process. Stainless steel 316L feedstock was injection-molded into the SP-molds with multi-pillar structures. To reduce the defects in plastic injection molding such as weld-line and short filling, which were developed around micro pillar structures of molded parts, the molding conditions for producing the SP-molds were optimized. This study also focused on the effects of metal particle size and processing conditions on the shrinkage, transcription and surface roughness of sintered parts.
  • 216 Evaluation on Anisotropic Behavior in Bending Deformation of CFRP Laminates Under Concentrated Load, OHARA Ayatoshi, NAKAO Yuki, NISHIYABU Kazuaki, Materials and processing conference, 2009, 17, "216, 1"-"216-2",   2009 11 06 , http://ci.nii.ac.jp/naid/110008617990
  • 407 Study on Electro-Fusion Joining Property of Cross-Linked Polyethylene Pipes, MUTO Masahiro, NISHIYABU Kazuaki, WATANABE Takashi, Materials and processing conference, 2009, 17, "407, 1"-"407-2",   2009 11 06 , http://ci.nii.ac.jp/naid/110008618070
  • Making and measuring in micro MIM manufacturing, NISHIYABU KAZUAKI, ANDREWS IAN, TANAKA SHIGEO, Met Powder Rep, 64, 9, 22, 25,   2009 10 01 , 10.1016/S0026-0657(09)70216-4, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902213955053910
    Summary:To be able to successfully form very small parts by micro metal injection moulding is not quite enough for series manufacturing. Dimensional measurement and quality evaluation requirements also need to be satisfied. These were among the objectives for a Japanese research group.... © 2009 Elsevier Ltd. All rights reserved.
  • Accuracy evaluation on SUS ultra-compact module 0.07mm gears manufactured by MIM, Kazuaki Nishiyabu, Shigeo Tanaka, Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy, 56, 268, 273,   2009 05 01 , 10.2497/jjspm.56.268, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=69549090073&origin=inward
    Summary:A microplanetary gears made of stainless steel has been developed by micro metal powder injection molding (μ-MIM) process. In this stud., the accuracy and the quality of ultra-compact planet gear (module: m = 0.07 m., number of teeth: z=24) was evaluated. Cross-sections of the gear teeth were observed with a digital microscope and dimensions of the teeth were measured with a digital image processing. The variations in dimensions and shape of gear teeth were systematically investigated for mol., green and sintered part., and heat treated ones. The accuracy classes of the ultra-compact planet gear were defined from four shape variations of gear teet., i.e. total runou., single pitch deviatio., accumulated pitch deviation and tooth profile deviation. The accuracy class was concluded as JIS N class seven which is a comparatively high precise levei for practical applications.
  • Polymer impregnation and pyrolysls process combined with powder space holder technique (PSH-PIP), Masaki Kotani, Aline Zimmer, Satoru Matsuzaki, Kazuaki Nishiyabu, Ceramic Engineering and Science Proceedings, 29, 27, 32,   2009 03 27 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=62849111738&origin=inward
    Summary:As a promising approach to improve the matrix microstructure of SiC fiber reinforced SiC matrix composite, a new polymer impregnation and pyrolysis process which is combined with powder space holder technique has been developed. PSH was employed for making porous structure in a matrix at the first PIP processing. It potentially contributes to efficient gas purge and uniform shrinkage during the polymer pyrolysis and is capable of being densified by the subsequent processing. Under the condition which had been found the best for matrix producing the monolith beforehand, unidirectional SiC/SiC composites were successfully fabricated. By comparing them with a composite obtained by the conventional PIP, the matrix of improved uniformity with smaller amount of process defects was certainly formed by PSH-PIP. The composites of the improved matrix exhibited higher mechanical properties such as tensile strengths and fracture toughness.
  • III : Recent Advance in Metal Powder Injection Molding, NISHIYABU Kazuaki, journal of the Japan Society for Testing Materials, 58, 1, 87, 92,   2009 , 10.2472/jsms.58.87, http://ci.nii.ac.jp/naid/130002085586
  • Basics of powder compaction and material processing III: Recent advance in metal powder injection molding, Kazuaki Nishiyabu, Zairyo/Journal of the Society of Materials Science, Japan, 58, 87, 92,   2009 01 01 , 10.2472/jsms.58.87, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=64349084909&origin=inward
  • POLYMER IMPREGNATION AND PYROLYSIS PROCESS COMBINED WITH POWDER SPACE HOLDER TECHNIQUE (PSH-PIP), KOTANI MASAKI, ZIMMER ALINE, MATSUZAKI SATORU, NISHIYABU KAZUAKI, Ceram Eng Sci Proc, 29, 9, 27, 32,   2009 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002221088891294
  • Insertion Testing of Polyethylene Glycol Microneedle Array into Cultured Human Skin with Biaxial Tension, TAKANO Naoki, TACHIKAWA Hiroto, MIYANO Takaya, NISHIYABU Kazuaki, Journal of Solid Mechanics and Materials Engineering, 3, 3, 604, 612,   2009 , 10.1299/jmmp.3.604, http://ci.nii.ac.jp/naid/130000106337
    Summary:Aiming at the practical use of polyethylene glycol (PEG) microneedles for transdermal drug delivery system (DDS), a testing apparatus for their insertion into cultured human skin has been developed. To simulate the variety of conditions of human skin, biaxial tension can be applied to the cultured human skin. An adopted testing scheme to apply and control the biaxial tension is similar to the deep-draw forming technique. An attention was also paid to the short-time setup of small, thin and wet cultured skin. One dimensional array with four needles was inserted and influence of tension was discussed. It was found that tension, deflection of skin during insertion and original curvature of skin are the important parameters for microneedles array design.
  • Advantages of SiC/SiC composites fabrication via micro-porous structure, Kazuaki Nishiyabu, Satoru Matsuzaki, Masaki Kotani, Progress of Composites 2008 in Asia and Australasia - Proceedings of the 6th Asian-Australasian Conference on Composite Materials, ACCM 2008, 40, 43,   2008 12 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84887545772&origin=inward
    Summary:To develop a heat-resistant composite material with high reliability in strength, this study was attempted to reduce the predominant defects occurred in the firing process of SiC precursor polymer by introducing a micro-porous structure. The hybrid production method combining the polymer impregnation and pyrolysis (PIP) process to the powder space holder (PSH) method which has been developed for micro-porous metal components in metal powder injection molding (MIM) was proposed. In the PSH-PIP process, space holding particles made of poly-methyl-methacrylate (PMMA) was mixed into SiC precursor polymer and removed by thermal pyrolysis to form a controllable micro-porous structure. The production conditions of SiC porous matrix for SiC fiber reinforced SiC composites were systematically investigated. The cracking problems in the pyrolysis process of SiC precursor polymer were drastically improved by optimizing the size and the fraction of space holding particles. As the results, the effectiveness of PSH-PIP process was proven by evidence that the mechanical properties of unidirectional SiC fiber reinforced SiC composites fabricated by VaRTM were enhanced.
  • Fabrication of silicon carbide porous body by powder space holder-polymer impregnation and pyrolysis method, Kazuaki Nishiyabu, Satoru Matsuzaki, Masaki Kotani, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 74, 988, 993,   2008 07 01 , 10.1299/kikaia.74.988, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=54749087434&origin=inward
    Summary:The hybrid process, Polymer Impregnation and Pyrolysis combined with Powder Space Holder (PSH-PIP) method, has been newly developed to improve the reliability in structure and mechanical properties of SiC/SiC composite. This process can yield an open micro-porous structure derived from a precursor polymer which is ready for being densified by a subsequent PIP processing. Systematic experimental study has been done for the effects of the size and the fraction of the space holding particles on the microstructure. Consequently, SiC porous bodies without any significant cracks were successfully obtained by achieving efficient gas purge and homogeneous thermal shrink-age.
  • 加水分解性マイクロ針による経皮性薬剤配送システム, 宮野 尚哉, 岡西 孝晃, 高野 直樹, 植村 建, 西籔 和明, 佐藤 裕之, 松崎 康司, 澤村 大輔, 花田 勝美, Drug Delivery System, 23, 3, 412, 412,   2008 05
  • Small is better if testing MIM nano theories, NISHIYABU KAZUAKI, TANAKA SHIGEO, Met Powder Rep, 63, 3, 28, 32,   2008 03 , 10.1016/S0026-0657(08)70040-7, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902298627312769
  • Accuracy evaluation of ultra-compact gears manufactured by micro-MIM process, Kazuaki Nishiyabu, Ian Andrews, Shigeo Tanaka, Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2008, 2, 325, 330,   2008 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84902138392&origin=inward
    Summary:The production of micro-size and micro-structured parts by metal powder injection moulding (MIM) process require more sophisticated techniques than conventional MIM. New techniques for the quality evaluation of those tiny parts are also necessary to be developed. A micro-planetary gear made of 17-4PH stainless steel has been developed by micro metal powder injection moulding (μ-MIM) process. This study describes the method of fabrication and quality evaluation of the ultra-compact plain gears (module: m=0.07, number of teeth: z=24) manufactured by μ-MIM. Cross-sections of the gear teeth were observed with a digital microscope and dimensions of the teeth were measured by image analysis. The variation in dimensions of teeth was evaluated for mold, green compacts, sintered parts and age-hardened ones. It was shown that those experiments contributed useful information on the quality of the ultra-compact gears.
  • Development of silicon carbide heat-resistant composites with micro-porous structure, Kazuaki Nishiyabu, Satoru Matsuzaki, Masaki Kotani, ICCM International Conferences on Composite Materials,   2007 12 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=79960072132&origin=inward
  • W01(10) Feasibility Study on Micro and High Functional Processings by Metal Powder Injection Molding, NISHIYABU Kazuaki, The Proceedings of Mechanical Engineering Congress, Japan, 2007, 0, 277, 278,   2007 , http://ci.nii.ac.jp/naid/110007086626
    Summary:The possibility of micro and high functional processings by metal powder injection molding (MIM) which uses effectively polymeric materials for enhancing both mold-ability and shape-retention were introduced. Sacrificial plastic mold inserted metal injection molding (SPiMIM) was developed to overcome some problems facing the realization of μ-MIM process. The molds were manufactured by LIGA process. Two types of transcription methods were adopted in LIGA/μ-SPiMIM process to obtain the sintered parts with multi pillars or fluidic channels. The effects of particle size on the quality of micro-structured parts were also investigated.
  • Micro metal powder injection moulding by LIGA lost form technology and using nano-size metal particle, Kazuaki Nishiyabu, Yasuhiro Kanoko, Shigeo Tanaka, Proceedings of the Euro Powder Metallurgy Congress and Exhibition, Euro PM 2007, 2, 137, 142,   2007 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84901818185&origin=inward
    Summary:The micro metal powder injection moulding using sacrificial plastic mould (SPmould), namely micro SP-mould insert MIM process has been developed to solve the problems specific to μ-MIM, e.g. difficulty of filling feedstock in narrow cavities and demoulding minute green compacts from the cavity. This study aims to improve the quality of micro-structured parts manufactured by LIGA/μ-SPiMIM process and to know the problems to be solved by using nano-sized metal particle. A PMMA resist film, which was prepared by irradiation process in LIGA, was used as SP-mould. The novel injection moulding machine which can achieve to mould without pelletizing was used to produce the tiny specimens with high trial efficiency and a small amount of feedstock. The effects of particle size on the quality of sintered parts were investigated. It was concluded that finer powder was better for transcription than coarser ones, but nano-sized metal powder also has accompanying technical issues which need to be modified to ensure good quality of sintered parts.
  • Net-Shape Manufacturing of Micro Porous Metal Components by Powder Injection Molding, NISHIYABU KAZUAKI, MATSUZAKI SATORU, TANAKA SHIGEO, Mater Sci Forum, 534/536, Pt.2, 981, 984,   2007 , http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202260207138583
  • Micro Metal Injection Molding Process and It's Application(Synergy by Microparticulation), MIURA Hideshi, OSADA Toshiko, TANAKA Shigeo, NISHIYABU Kazuaki, ISSEMP : proceedings of International Symposium on Synergistic Effects of Materials and Processing, 2006, 15, 18,   2006 09 19 , http://ci.nii.ac.jp/naid/110006676662
    Summary:In order to improve the quality of MIM products, micro-injection molding process were focused. Two types of injection machines with different capacity were used for producing the micro dumbbell specimen. Sintered density and strength of micro dumbbell specimens were determined. It is clarified that the specimens produced by smaller injection machines were smaller variation in sintered density and strength. Moreover, gas surface treatment is considered to be especially effective for Titanium because of its high reactivity. In this study, we investigated the gas nitriding mechanism in titanium sintered parts produced by MIM process. The effects of specimen size on the nitriding process was investigated, because the size of micro metal injection molding (μ-MIM) product is so small and the specific surface of that product is so large that high performance mechanical and functional properties can be easily obtained by the nitriding treatment.
  • Dimensional accuracy of micro-porous metal injection and extrusion molded components produced by powder space holder method, Kazuaki Nishiyabu, Satoru Matsuzaki, Shigeo Tanaka, Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy, 53, 776, 781,   2006 09 01 , 10.2497/jjspm.53.776, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=33845536207&origin=inward
    Summary:A production method for porous metal components has been developed by applying powder space holder (PSH) method to metal powder injection molding (MIM) process. The PSH-MIM method has an industrial advantage which is capable of net-shape manufacturing the micro-size porous metal products with complicated shapes and controlled porosity and pore size. In this study, a small impeller made of stainless steel 316L was manufactured by injection molding, and a plate specimen was produced by extrusion molding to evaluate the dimensional accuracy of the porous sintered parts produced by the PSH-MIM method. The effects of combinations of size and fraction of space holder particle on the dimensional deviation and its coefficient of variance were investigated. It was concluded that the PSH-MIM method could manufacture commercially micro-porous metal components with high dimensional accuracy.
  • Size effects of gas nitriding of injection molded Titanium parts, Toshiko Osada, Shigeo Tanaka, Kazuaki Nishiyabu, Hideshi Miura, Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy, 53, 745, 749,   2006 09 01 , 10.2497/jjspm.53.745, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=33845515871&origin=inward
    Summary:In this study, gas nitriding was performed to various sizes of Titanium parts which were produced by metal injection molding (MIM) process, in order to add the high functionality with low processing cost. It was shown from the experiments that the nitriding treatment was useful for increasing the hardness of the surface which microstructure changed to the TiN and acicular α-Ti phase. With respect to the effect on the size of parts, micro dumbbell specimen had around five times higher content of nitrogen than block ones. It was suggested that the size of μ-MIM products is so small that the surface treatment contribute significantly and easily to improve the properties, especially gas nitriding process is one of effective surface treatment methods for high functionality of μ-MIM products.
  • Effects of metal powder characteristics on the compactibility and sinterability in micro metal injection molding process, Toshiko Osada, Kazuaki Nishiyabu, Satoru Matsuzaki, Shigeo Tanaka, Hideshi Miura, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 72, 148, 153,   2006 01 01 , 10.1299/kikaia.72.148, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=33645145996&origin=inward
    Summary:Metal injection molding for tiny parts is called micro metal injection molding, " μ-MIM" which is considered to be one of promising process to manufacture the micro parts for various applications. In μ-MIM, the feedstock properties, particularly particle size and shape of metal powder are significantly important for the quality of micro parts. The purpose of this study is to investigate the effect of metal powder characteristics on the compactibility and sinterability. The three types of powders (3 μm and 9 μm water-atomized powders and 3 μm gas atomized powder) were used for the comparison. The melt viscosity of the feedstock was utilized as an index for evaluation of compactibility by injection moding. Then the spring shape of green compact specimen was produced by the micro injection molding machine. The green density was also evaluated for compactibility of the feedstock. The density and grain size of sintered specimens were investigated by changing sintering temperature and time.
  • Development of micro metal injection moulding inserted sacrificial plastic mould, Kensuke Taira, Kenji Okubo, Shigeo Tanaka, Kazuaki Nishiyabu, Euro PM 2005: Powder Metallurgy Congress and Exhibition, 2, 391, 397,   2005 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84901925613&origin=inward
    Summary:The miniaturization of dimension and structures in metal injection moulding (MIM) is faced with various technical problems, such as incomplete filling to narrow cavity, failure in demoulding of fragile green compacts, and deformation in debinding and sintering process. The production method of micro sacrificial plastic mould insert metal injection moulding, namely μ-SPiMIM process, has been proposed to solve such specific problems involving the miniaturization of MIM. The sacrificial plastic mould was prepared by injection-moulding Polymethylmethacrylate (PMMA) into the steel mould machined or Ni mould electroformed in LIGA process, and by rapid proto-typing. Stainless steel 316L feedstock was injection-moulded into several types of SP-moulds with 3 dimensional complex structures, such as 1) zigzag shaped spring, 2) multi-pillar structures and 3) micro-impeller. The green compact was demoulded as one component with SP-mould, which was decomposed along with binder constituent in the feedstock in thermal debinding process. This study focused on the difference of fabrication method for SP mould, and demonstrated those characteristic sintered parts. The effects of materials and processing conditions on the shrinkage, transcription and surface roughness of sintered parts were also evaluated with laser shape measurement and SEM observation.
  • Fabrication method of micro structured parts by metal injection molding with LIGA process, Satoru Matsuzaki, Shigeo Tanaka, Kazuaki Nishiyabu, Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy, 52, 55, 59,   2005 01 01 , 10.2497/jjspm.52.55, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=17044440157&origin=inward
    Summary:This study aims to investigate the possibility for producing micro metal structured parts by applying micro metal injection molding (μ-MIM), the insert μ-MIM methods based on LIGA process were proposed, which used two types of sacrificial molds for MIM processing as following; 1) PMMA (polymethylmethacrylate) resist and 2) PMMA mold injected in Ni electroformed mold. These processes were named "LIGA/μ-iMIM method" and the feasibility was checked by using SUS316L stainless steel powders. It was demonstrated that this method had a great potential to produce micro metal structured parts, also confirmed that the finer metal powders were better for their transcription than the coarse one.
  • Formation mechanism of micro porous metals produced by powder space holder method, Satoru Matsuzaki, Shigeo Tanaka, Kazuaki Nishiyabu, Euro PM 2005: Powder Metallurgy Congress and Exhibition, 2, 135, 141,   2005 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84901936410&origin=inward
    Summary:A novel production method for the metal components with micro-sized porous structures has been developed by applying powder space holder (PSH) method to metal powder injection moulding (MIM) process. The representative materials are stainless steels. The aim of this study is to clarify the effects of material combinations on the pore formation and some physical properties of sintered porous specimens. The green compacts were moulded by hot pressing for simplification using various porous compounds which were prepared with changing the combinations in size of metal powder and space holding particle, and were sintered at various temperatures. It was confirmed that the size of metal powder and space holding particle in addition to sintered temperature was main factors affecting significantly for the pore size, porosity, surface area and shrinkage of sintered porous specimens. It was confirmed that the method proposed was useful in producing the metal components with micro-sized porous structures.
  • Quality improvement of micro metal injection moulding using micro/nano powders, Kazuaki Nishiyabu, Kenichi Kakishita, Toshiko Osada, Satoru Matsuzaki, Shigeo Tanaka, Euro PM 2005: Powder Metallurgy Congress and Exhibition, 2, 357, 363,   2005 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84901943863&origin=inward
    Summary:Micro metal injection moulding (μ-MIM) needs more sophisticated techniques than the conventional MIM. The use of finer metal powders is one of the solutions to improve the dimensional accuracy and surface roughness of sintered products. This study aims to investigate the effects of hybrid micro/nano powders in μ-MIM process. To produce the tiny specimens with high trial efficiency and a small amount of feedstock, a novel experimental machine which can achieve to mould without pelletizing was used. Small dumbbell specimens were produced with changing the binder content and the fraction of nano-scale copper powder. The effects of nano-scale copper powder addition on the tap density of mixed powder, the viscosity of feedstock and microstructure of sintered bodies were discussed.
  • Fabrication and evaluation of micro parts by metal injection molding, Toshiko Osada, Kazuaki Nishiyabu, Satoru Matsuzaki, Shigeo Tanaka, Hideshi Miura, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 70, 1522, 1528,   2004 10 01 , 10.1299/kikaia.70.1522, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=11144291998&origin=inward
    Summary:This study describes the micro evaluation methods for investigating the feedstock properties and the process conditions for industrial mass production of micro parts by Metal Injection Molding (MIM). The effects of feedstock properties such as particle size and powder loading on the sintered properties of micro-dumbbell specimens were investigated under various injection-molding conditions. Small particle size and high powder loading significantly improved the quality such as density and tensile strength, as well as yield percentage in producing sound micro-dumbbell sintered specimens. Deformation and fracture propagation behaviors were observed with the in-situ SEM tensile test which was useful to comprehend the influences of feedstock properties on the mechanical properties of the micro MIM (μ-MIM) products.
  • Evaluation on the homogeneity of feedstock for micro size parts produced by MIM, Toshiko Osada, Kazuaki Nishiyabu, Yasuo Karasaki, Shigeo Tanaka, Hideshi Miura, Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy, 51, 435, 440,   2004 06 01 , 10.2497/jjspm.51.435, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=4344695336&origin=inward
    Summary:Producing the micro size parts by Metal Injection Molding (MIM) needs more sophisticated technique than the conventional injection molding. Especially, inhomogeneous state of the feedstock will strongly influence on the quality of the final products. In order to evaluate the mixing and palletizing conditions of the feedstock, statistical variations of density and binder contents in individual pellet were investigated by the weight measurement. These variations were discussed with coefficient of variation. The micro dumbbell specimens were fabricated using the feedstock, and the density and strength were investigated. Moreover, in order to improve the feedstock properties, re-pelletizing was performed. It was found that the homogeneity of the pellet was one of the important factors for quality of the micro size parts produced by MIM.
  • Strain concentrations in woven fabric composites with holes, Surya D. Pandita, Kazuaki Nishiyabu, Ignaas Verpoest, Composite Structures, 59, 361, 368,   2003 12 01 , 10.1016/S0263-8223(02)00242-8, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0346665862&origin=inward
    Summary:A strain mapping technique, namely digital photogrammetry, was used to investigate the tensile strain field of woven fabric composites in the presence of stress concentrations caused by geometrical defects consisting of circular or elliptical holes. Plain woven fabrics were used. The strain mapping technique clearly revealed the strain concentrations near the singularity. The strain concentrations are influenced by the tensile loading direction and the hole dimension relative to the size of the unit cell of the plain woven fabrics. A preliminary comparison of stresses approximately calculated from the strain field and theoretical stresses calculated from existing models such as Lekhnitskii's model is also presented. © 2003 Elsevier Science Ltd. All rights reserved.
  • Examples of Non-contact Strain Field Measurement by Advanced Digital Images Correlation Technique, Nishiyabu Kazuaki, Akabane Takahiko, Nonaka Hiroshi, The Proceedings of the Symposium on Evaluation and Diagnosis, 2003, 0, 154, 159,   2003 , http://ci.nii.ac.jp/naid/110002495855
  • Numerical analysis and in-situ SEM observation of damage development for woven fabric composite materials, Yasutomo Uetsuji, Masaru Zako, Kazuaki Nishiyabu, Zairyo/Journal of the Society of Materials Science, Japan, 51, 1147, 1153,   2002 10 01 , 10.2472/jsms.51.1147, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0036819887&origin=inward
    Summary:Although woven fabric composite materials have high performance, it is very difficult to reveal their mechanical behaviours due to the geometric complexity by theoretical analysis. Especially under damage development, several kinds of failure mode such as matrix cracking, fiber breaking and transverse cracking in fiber bundle affect the mechanical behaviour strongly. In order to analyze the mechanical behaviour, three-dimensional finite element analytical procedure based on damage mechanics has been developed. In this paper, the developed procedure is applied to plain woven fabric composites, and the mechanical behaviour under damage development by on-axis tensile load has been analyzed. On the other hand, on-axis tensile test has been performed in SEM and the change development at the edge cross-section of specimen has been observed. As a result, it can be confirmed that the calculational and the experimental results have a good agreement. Then, the mechanical behaviour depends on the edge effect of free side surface. Therefore the effect of free edge has been evaluated quantitatively by numerical analysis from comparison with mechanical behaviour under periodic boundary condition without free side surface. From the above results, it is recognized that the proposed procedure is very useful for the material design of woven fabric composite materials.
  • Evaluation on mechanical properties and functionalities of anti-bacteria and resist-corrosion for Cu-added stainless steel (SUS304L) by MIM, Yooshikazu Masai, Masashi Ishida, Shigeo Tanaka, Kazuaki Nishiyabu, Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy, 49, 834, 840,   2002 09 01 , 10.2497/jjspm.49.834, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0036763431&origin=inward
    Summary:The effect of copper-added content and sintering temperature on the mechanical properties and functional performances such as anti-bacteria and resist-corrosion for the stainless steel by metal injection molding was investigated. The specimens were prepared by injection molding the mixed powders of water-atomized SUS304L and Cu with poly-acetyl binder. The green compacts were prepared at five steps of copper-added content from 0mass%Cu to 5mass%Cu and they were sintered at the six steps of temperature from 1050 to 1350°C for 7.2ks in Ar gas after the debinding process at 600 °C for 7.2 ks in N2 gas. The relative density and tensile strength of sintered compacts showed the minimum values by addition of 5mass%Cu and 8mass%Cu, respectively. They were modified up to original value by addition of 10mass%Cu and sintering at 1100°C. The anti-bacterial test based on film contact to bacilli and the quantitative analysis of copper ion dissolved to water showed high effective as increasing the copper-added content. It was also confirmed from the measurement of pitting potential that copper addition modifies the resist-corrosion performance.
  • Preparation of flexible interphase in FRP and determination of the finite thickness, Naoyuki Oya, Kazuaki Nishiyabu, Hiroyuki Hamada, Zairyo/Journal of the Society of Materials Science, Japan, 51, 483, 488,   2002 05 01 , 10.2472/jsms.51.483, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0036563315&origin=inward
    Summary:This paper describes experimental developments for a concise preparation method of flexible interphase in commonly used GFRP and determination methods of the finite interphase thickness. The preparation scheme of the flexible interphase basically comprises surface coating of glass fibres with toughened epoxy resin. The finite thickness of the flexible interphase is determined by means of scanning electron microscopy equipped with energy dispersive X-ray element analyser and visco-elasticity image analysis featured in a scanning probe microscope. Certain evidences are successfully observed for the flexible interphase to be created by means of the proposed preparation method. However, it is found that the interphase thickness obtained from each method exhibits different values due to the particular sample status. The model composite used in the X-ray method contains a platinum layer as a boundary-indicator between the flexible interphase and the matrix resin. The platinum layer may hinder the interacting diffusion between the interphase and the matrix during the curing process, and this probably causes the broader interphase to remain in the model composite used in the X-ray method. Both methods are found to be useful to evaluate the interphase thickness around the single glass-filament at the microscopic level. However, those results show relatively large scatters; this means that more efforts are still needed to create the interphase uniformly around the glass fibres using more sophisticated surface treatment techniques.
  • Deep-drawing simulation of knitted fabric reinforced thermoplastics by homogenization theory and experimental verification, N. Takano, Y. Ohnishi, K. Nishiyabu, M. Zako, Zairyo/Journal of the Society of Materials Science, Japan, 50, 461, 467,   2001 05 01 , 10.2472/jsms.50.461, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0035329885&origin=inward
    Summary:A novel computational method for deep-drawing simulation of composite materials has been proposed with taking a three-dimensional continuum mechanics approach. The most notable feature is the consideration of micro-macro coupling effects by the mathematical homogenization theory. The homogenized properties and the constitutive law are evaluated carefully using the three-dimensional microstructure model under the large deformation and biaxial loading conditions. In this paper, the knit reinforcement of aramid fiber is studied, which has very complex microstructure architecture. The polypropylene is used as the matrix. The newly developed deep-drawing simulation provides us the macroscopic deformation, strain, stress and stiffness distribution as well as the largely deformed microstructures in the deep-drawn product. The high-speed computing technique which has been developed in the previous report enables us to carry out the micro-macro coupled nonlinear analysis easily on the personal computer. The experimental work has also been conducted, and the largely deformed microstructures are compared between experiment and simulation. A good coincident was obtained, which implies the validity and reliability of the proposed computational method.
  • Fabrication and mechanical properties of polymorphism composites inserted with knitted polyethylene fabric reinforced polyethylene, T. Fukui, A. Nakai, H. Hamada, K. Nishiyabu, International SAMPE Symposium and Exhibition (Proceedings), 46 II, 2409, 2420,   2001 01 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0034822149&origin=inward
    Summary:In this study, reinforcement and matrix derived from the same kind of thermoplastics were used for polymorphism composite materials. The advantage of this material is not needed to take a chemical micmatch in adhesion into accout because the active cohesive force acts in the interface between fiber and matrix. The concept of such a material combination in composites can be applied for many kinds of thermoplastic materials. In this paper, Weft-knitted Polyethylene fabric reinforced Polyethylene sheet (namely, PE/PE sheet) was prepared by film stacking method. The effects of mold temperature in film stacking process on mechanical properties of PE/PE sheet were investigated. Injection molding specimens were prepared by inserting the PE/PE sheet, and low-density Polyethylene was used as matrix for injection molding. Mechanical properties of PE/PE injection composites were investigated. The tensile strength of PE/PE composites was higher than that of only PE matrix. The experimental results give evidence of t he strong interface in PE/PE composite. In addition, the volume fraction of knitted fabric injection composite was only 4%, nevertheless the reinforcing efficiency is surprisingly high for the low fraction of reinforcement.
  • Formulation of homogenization method applied to large deformation problem for composite materials, N. Takano, Y. Ohnishi, M. Zako, K. Nishiyabu, International Journal of Solids and Structures, 37, 6517, 6535,   2000 11 01 , 10.1016/S0020-7683(99)00284-X, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0034325851&origin=inward
    Summary:In order to analyze the mechanical behaviors of composite materials under large deformation, the formulation of the homogenization method is described. In this formulation, assuming that the microstructures in a local region of the global structure are deformed uniformly and that consequently the microscopic periodicity remains in the local region under large deformation, the microscopic deformation is precisely defined by the perturbed displacement and product of macroscopic displacement gradient and microscopic coordinates. Finally, microscopic and macroscopic equations are obtained. The above mentioned assumption of the periodicity of microstructures is experimentally validated. The computer program is also developed according to this formulation, and the large deformation is analyzed for the unidirectional fiber reinforced composite material and the knitted fabric composite material.
  • Effect of interphase properties on initial damage in embedded single fiber transverse tensile test, Kazuaki Nishiyabu, Atsushi Yokoyama, Masaru Zako, Zairyo/Journal of the Society of Materials Science, Japan, 48, 446, 453,   1999 05 01 , 10.2472/jsms.48.446, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0032662432&origin=inward
    Summary:The embedded single fiber transverse tensile test has been proposed as a new experimental evaluation method on composite interfaces. The effect of surface treatment on microscopic damage, such as the interfacial debonding and matrix cracking around a fiber was investigated by in-situ SEM observation, when the transverse tensile load to the fiber longitudinal direction was applied to an embedded single fiber composite. The experimental result revealed that the surface treatment condition of fibers has an influence on the initiation and propagation of interfacial debonding and matrix cracking around a single fiber. In addition, the effect of interfacial properties on microscopic damage was investigated by a finite element analysis. The analysis was carried out by using a three layers model, which was modeled separately, fiber, matrix and interphase into the test specimen. The property for the interphase was assumed to be orthotropic, i.e. both tensile and shear moduli of the interphase are dealt independently to express the role of interphase for stress bearing and stress transfer separately. The effect of interphase properties was investigated by changing the tensile and shear moduli of the interphase. The reasonable elastic properties of the interphase were obtained by comparing the computational results with experimental ones. The Hoffman's failure criterion was used for judging of the damage in the interphase and the matrix. The validity of this analytical method is verified by comparing the analytical results with the experimental ones.
  • Evaluation of damage behaviors on woven cloth fabric reinforced composites by in-situ SEM observation - effect of surface treatment, Kazuaki Nishiyabu, Atsushi Yokoyama, Masaru Zako, Zairyo/Journal of the Society of Materials Science, Japan, 48, 430, 437,   1999 05 01 , 10.2472/jsms.48.430, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0032662431&origin=inward
    Summary:The effect of interfacial properties on damage behaviors of woven cloth fabric reinforced composites has been investigated by the edge cross-sectional observation of laminate under the tensile load in SEM. Test specimen used is vinyl ester resin matrix laminated composite reinforced by glass woven cloth. It is obvious that the surface treatment conditions of the fiber have affected the appearance of microscopic damages, such as the interfacial debonding and matrix cracking into the fiber bundle, or the generation of AE event. In the case of the fiber treated with the silane-coupling agent suitable for the matrix resin, only a few cracks occur into the fiber bundle just prior to the maximum load, and AE events generate fewer. In the case of chemical-mismatch treated fiber or non-treated fiber, however, much more cracks occur into the fiber bundle at the lower tensile load, but the generation behavior of AE events differs with each other. It is found by in-situ SEM observation that the fiber surface treatments have affected the initiation and progression of microscopic damage under the tensile load. Thus, it can be concluded that in-situ SEM observation with measuring both tensile load and AE event count is a useful evaluation method for understanding the effect of interfacial property on microscopic damage behavior.
  • Evaluation of interphase mechanical properties by embedded single fiber transverse tensile test, K. Nishiyabu, M. Zako, Proceedings of the International Conference on Computer Methods in Composite Materials, CADCOMP, 225, 235,   1998 12 01 , http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0032293768&origin=inward
    Summary:This paper describes the modeling methodology on composite interphase, which takes the interfacial region into consideration and deals with tensile and shear moduli for the region independently. From in-situ SEM observation results by the embedded single fiber transverse tensile test, it has been revealed that the fiber surface treatment conditions have an influence on the generation and propagation of the interfacial debonding and matrix cracking around a single fiber. Damage simulation in this test is carried out by a finite element analysis. Hoffman's failure criterion is used for a judgment of damage in the interphase and the matrix. The reasonable elastic properties for the interphase are obtained by comparison of the computational with the experimental results. The effect of surface treatment conditions is investigated by changing the tensile strength of the interphase. The qualitative validity of this analytical methodology is verified by comparing tho analytical results with the experimental ones.
  • Assessment of the influence of interfacial properties on stress transfer in composites by a numerical approach, Kazuaki Nishiyabu, Atsushi Yokoyama, Hiroyuki Hamada, Composites Science and Technology, 57, 1103, 1111,   1997 12 01 , 10.1016/S0266-3538(97)00009-2, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0031213511&origin=inward
    Summary:To investigate the effect of interfacial properties on stress transfer by a numerical approach, a finite element model has been used where the fiber, the matrix and the interphase were treated separately. When the interphase was assumed to be orthotropic, an influence of the interfacial shear stiffness on stress transfer was evaluated from the axial tensile stress transferred from the matrix to the fiber by passing through the interphase. The influence of fiber breakage and interfacial debonding or matrix cracking on the stress distribution has also been studied. When the shear stiffness of the interphase is greater than that of the matrix, a high stress concentration appears near the fiber break point. However this stress concentration disappears when the fiber breakage occurs together with interfacial debonding or matrix cracking. It was therefore suggested that the fiber fracture propagation mode might be changed by altering the shear stiffness of the interphase and by the existence of interfacial debonding or matrix cracking. Thus it was obvious that the proposed FE numerical approach and the concept of material constants of the composite interphase might be appropriate for investigating the influence of the interfacial properties on stress transfer. © 1997 Elsevier Science Limited.
  • Effect of graded interphase properties on stress transfer mechanisms in single fiber composite, Kazuaki Nishiyabu, Atsushi Yokoyama, Masaru Zako, Zairyo/Journal of the Society of Materials Science, Japan, 46, 335, 342,   1997 12 01 , 10.2472/jsms.46.335, http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0031123610&origin=inward
    Summary:In order to investigate the effect of the interfacial property on stress transmissibility, the finite element analytical model in which fiber, matrix and interphase were divided independently into mesh elements has been applied. The interfacial region was assumed as orthotropy. The concept of orthotropy on the composite interphase is suitable for investigating the effects of stress bearing and stress transfer on mechanical behaviors. This paper deals with the study on the influence of the gradient interphase on the stress transfer. Either the axial tensile modulus or the shear modulus was varied gradually in the interphase. From the analytical results, it is concluded that the difference in gradient distribution of the interfacial tensile modulus or the interfacial shear modulus affected both the interfacial stress transmissibility and stress bearing in the interphase. Therefore, it is obvious that this numerical analytical modelling on composite interface is suitable for the numerical approach of fiber reinforced composites, because it is possible to represent separately stress transfer and stress bearing as the role of the interface/interphase.

Research Grants & Projects

  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Fabrication of High Aspect Micro-structured Parts by Nano-fiber Imprinting Plastic Molding, This study aims to fabricate the micro-structured parts using nano-powder via compaction process by printing. The sacrificial plastic mold (SP-mold) which is derived from melting nanofiber produced by electron spinning (ES) method which provides a simple and versatile method for generating ultra-thin fibers using variety of materials is used. The original form made of silicon has micro-sized structures with line and space patterns, circular hole or column. The material used for printing is the mixture of nano-scale Ni or TiO2 powders and water-soluble binder. It was shown from the results of surface observation that the SP-mold with micro-structures of 1 micron wide and 10 micron high in minimum size could be obtained finely, and also the sound sintered parts were obtained.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Evaluation of Transcription on Micro-structured Parts by Nano-Imprint Lithography Sacrificial Plastic Mold Insert Powder Injection Molding, This study aims to develop the manufacturing method of micro-structured parts by the metal powder injection molding (MIM) inserted micro-sacrificial plastic molds which were prepared by nano-imprint lithography (NIL) technique. In this process named NIL/μ-SPiMIM, the feedstock composed of nano-sized copper powder and polyacetal-based binder was adequately prepared and molded into polymethylmethacrylate films with fine line-scan structures, and the molded parts were sintered in a reductive gas atmosphere followed by solvent debinding of the films. The behavior in debinding and sintering was investigated by thermo-gravimetric analysis, carbon and oxygen analysis and SEM observation. The effects of sintering temperature on sintered density and shrinkage, profile accuracy were evaluated systematically. It can be concluded that the manufacturing method named NIL/μ-SPiMIM proposed in this study has great potential to produce precisely 3 dimensional complex metallic parts with fine micro-structures.