Faculty Profiles - NARAHARA Hiroyuki

Papers - NARAHARA Hiroyuki

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金属光造形機を用いたダイカスト金型用鋳抜きピンの熱疲労評価

西田拓人, 楢原弘之, 中村克昭

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2019 ( 0 ) 17 - 18 2019.01

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>ダイカスト金型には，成形サイクルでの急激な加熱と冷却の繰り返しが原因の熱疲労によってクラックが生じることがある．穴のあいた鋳物を成形するために金型に組み込む鋳抜きピンは，特に熱疲労による不良が起きやすい．本研究では，金属光造形機により鋳抜きピンを作成し，成形サイクルの中でピンに発生するクラックの位置や大きさを観察するために熱疲労評価を行う．</p>

DOI： 10.11522/pscjspe.2019S.0_17

Other Link： https://ci.nii.ac.jp/naid/130007702467

金属光造形法を用いた金型内部のメッシュ化による反り低減効果の評価

龍野嘉基, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2019 ( 0 ) 500 - 501 2019.01

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>金属光造形法では溶融した金属が凝固する際に収縮することで，造形物に反りが発生する問題がある．反りが発生すると金型としてそのまま使用できず後処理が必要となるため，金属光造形法において反りの低減は重要課題となっている．本研究では，造形物の内部構造や内部の造形条件に着目した反り低減手法の構築を目的としている．本報では，金型を模した造形物内部のメッシュ化を行い，反り低減効果の検証を行ったため報告する．</p>

DOI： 10.11522/pscjspe.2019S.0_500

Other Link： https://ci.nii.ac.jp/naid/130007702688

The Effect of Atmospheric Pressure Plasma on Inter-Laminar Adhesion Strength of FDM Parts Manufactured with Different Functional Polymers

コペッチ・ロドリゲズシーロ, 楢原弘之, 是澤宏之, 中谷久之

精密工学会学術講演会講演論文集 ( The Japan Society for Precision Engineering ) 2019 ( 0 ) 519 - 520 2019.01

Authorship：Corresponding author Language：English Publishing type：Research paper (conference, symposium, etc.)

<p>Atmospheric Pressure Plasma (APP) is widely used as a surface treatment method and is capable of increasing the Surface Free Energy of a range of polymers. In this research, the effect of APP treatment on the resulting tensile strength (TS) of functional FDM polymers was analyzed. Multi-material samples of functional polymers were manufactured using mainly polyamide and conductive PLA as objects of study. The interface between those materials were treated with APP in different conditions and the TS data compared.</p>

DOI： 10.11522/pscjspe.2019S.0_519

Other Link： https://ci.nii.ac.jp/naid/130007702705

FDM造形物を用いた接触分布検出センサの電極形成手法の研究

竹下未来, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2019 ( 0 ) 524 - 525 2019.01

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>熱溶解積層法（FDM）は，熱可塑性樹脂材料を加熱し，ノズルから材料を吐出，積層する造形手法であり，ノズルを増やすことで容易に材料を変更できるという利点がある．著者らは非導電性材料と導電性材料を用いてFDM造形物内部に電極や配線回路を形成することで，接触分布検出センサの製作を目指している．本報では，FDM造形物の内部に電極を形成するために必要な条件について検討した．</p>

DOI： 10.11522/pscjspe.2019S.0_524

Other Link： https://ci.nii.ac.jp/naid/130007702698

Evaluation of Melt Pool in Metal SLS Simulation

Tankasem Warot, 百田和矢, 楢原弘之, 是澤宏之, 村松壽晴, 青栁裕治

精密工学会学術講演会講演論文集 ( The Japan Society for Precision Engineering ) 2019 ( 0 ) 502 - 503 2019.01

Authorship：Corresponding author Language：English Publishing type：Research paper (conference, symposium, etc.)

<p>In this research, in order to evaluate the applicability of metal SLS analytical software to the reality, we compared the melt pool values obtained by the software with the melt pool of manufactured objects. Secondly, the effect of laser output parameter on melt pool dimension was investigated and the results reported.</p>

DOI： 10.11522/pscjspe.2019S.0_502

Other Link： https://ci.nii.ac.jp/naid/130007702690

CADを用いた歯面修整のための歯車と工具の相対位置制御シミュレーション

下坂隆昭, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2019 ( 0 ) 718 - 718 2019.01

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>自動車用トランスミッションには伝達歯車が組み込まれている．これらを高速度・高負荷で回転する際の振動・騒音は自動車の快適性を損なう原因となる．抑制する方法として剛性の高い素材の使用やより高精度の歯車の使用があげられる．本研究では，今後のトータルコスト低減と高精度化のために歯研工程における歯車と工具の相対位置制御のシミュレーションを行う．</p>

DOI： 10.11522/pscjspe.2019S.0_718

Other Link： https://ci.nii.ac.jp/naid/130007702750

Wear observation for end-mill tool by machine learning through Acoustic Emission

INOUE Kento, KORESAWA Hiroshi, NARAHARA Hiroyuki, ISHIDA Syuichi, MOTOMURA Taisei, TABARU Tatsuo

The Proceedings of The Manufacturing & Machine Tool Conference ( The Japan Society of Mechanical Engineers ) 2019 ( 0 ) D22 2019.01

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

This paper deals with realizing proper usage for cutting tool under condition-based maintenance. In this maintenance, it is important to change cutting tool before breakage of tool. For instance, improper change for tool before tool life will be incurred machining cost beyond necessity. In other words, the change requires to estimate precise time and/or condition of tool life. We assumed the wear of tool should be tool life in experiments. In general, it is hard to evaluate condition and/or amount of tool wear during metal cutting. In this paper, tool state is evaluated, using signal from thin AE (Acoustic Emission) sensor set up on machine tool. When the tool is worn, it is well-know that anomaly vibration will be occurred from rotating cutting tool and reduction of cutting performance will be caused. Anomaly vibration is detected by using machine learning and auto encoder with reconstruction error. As a result of experiments, we confirmed that there is high regression between amount of wear of tool and reconstruction error.

DOI： 10.1299/jsmemmt.2019.13.D22

Other Link： https://ci.nii.ac.jp/naid/130007836434

Work navigation using image recognition in metal laser additive manufacturingaiming attechnologyinheritance

Yamanaka Kohei, Narahara Hiroyuki, Koresawa Hiroshi

Proceedings of JSPE Semestrial Meeting ( The Japan Society for Precision Engineering ) 2018S ( 0 ) 255 - 256 2018.03

Intermittent Monitoring of FDM Parts′ Surface Conditions During the Manufacturing Process: A Newly Designed Automated Test Platform

Copetti Rodriguez Ciro, Narahara Hiroyuki, Koresawa Hiroshi, Nakatani Hisayuki, Shimizu Akimitsu

Proceedings of JSPE Semestrial Meeting ( The Japan Society for Precision Engineering ) 2018S ( 0 ) 399 - 400 2018.03

Authorship：Corresponding author Language：English Publishing type：Research paper (conference, symposium, etc.)

<p>Multi-material printing has been an important research field for the past years. Through the fabrication of multi-material parts, the capabilities and complexity of parts obtained through additive manufacturing increases yet again. However, improving the interface strength between different material is a challenge that needs to be overcome and several kinds of treatment can be used to investigate this matter. This paper presents the development of a test platform capable of performing surface treatments as well as part measurements concurrent to the print process, without human manipulation.</p>

DOI： 10.11522/pscjspe.2018s.0_399

FDM法における特殊雰囲気下での3Dプリンティングの検討

田坂明大, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2018S ( 0 ) 395 - 396 2018.03

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>FDM法（熱溶解積層法）とは，付加製造法を用いる3Dプリンティングの方法の一つである．溶解した熱可塑性樹脂を堆積・固化させ，それを繰り返すことにより，任意の三次元形状を造形する手法である．本研究では，FDM法における3Dプリンティングを特殊雰囲気下で行うことのできる機構を作製し，成形実験により．特殊雰囲気における造形物への影響を評価する．</p>

DOI： 10.11522/pscjspe.2018s.0_395

金属光造形法の造形条件が余剰硬化現象に与える影響の評価

龍野嘉基, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2018S ( 0 ) 407 - 408 2018.03

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>金属光造形複合加工法では過剰なレーザー出力によって必要以上の金属粉末まで焼結する余剰硬化現象が発生する．この現象によって焼結後の表面が荒れ，切削加工時間の長時間化に繋がっている．焼結条件を適切に設定することで高い金属充填率を保ったまま余剰硬化の発生を抑えることができると期待される．本研究ではレーザーや造形物形状を変えて造形実験を行い，各種造形条件が余剰硬化に与える影響を定量的に評価する．</p>

DOI： 10.11522/pscjspe.2018s.0_407

金属光造形における残留応力による造形ひずみの低減を目的とした条件因子の調査

又吉ジョナサン, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2018S ( 0 ) 405 - 406 2018.03

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>金属光造形はレーザーで金属粉末を溶融凝固しているため熱が発生してしまう。それが原因となってベースプレート(母材)に残留応力という形で現れ、造形後にひずみを引き起こしたり破断する原因となる。そこで本研究では造形におけるどの因子がひずみに影響を及ぼすのかを調査すると同時に造形物の精度の検証も行うことを目的とする。</p>

DOI： 10.11522/pscjspe.2018s.0_405

通気性射出成形金型の低エネルギー成形に関する研究

吉岡亮祐, 楢原弘之, 是澤宏之

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2018S ( 0 ) 239 - 240 2018.03

Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>通気性金型は，射出成形中に金型内で残留するガスを起因とした成形不良の低減対策として有効である．また，複雑形状部や薄肉部へ対して，低射出圧での溶融樹脂の充填が可能となり，成形サイクル中の射出成形機の消費電力削減が期待できる．本研究では，成形条件や通気特性，成形品形状を変化させた際の成形品の樹脂充填量と成形機の各種消費電力，金型内圧力を測定することで，通気性金型による電力削減効果を調査する．</p>

DOI： 10.11522/pscjspe.2018s.0_239

樹脂3Dプリンタによる異種材料接合の接合強度向上に関する研究

清水章充, 楢原弘之, 是澤宏之, 中谷久之, コペッチ・ロドリゲズシーロ

精密工学会学術講演会講演論文集 ( 公益社団法人精密工学会 ) 2018S ( 0 ) 397 - 398 2018.03

Authorship：Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>熱溶解積層法を用いた3Dプリンタは試作品の迅速な造形と切削法では不可能な複雑な内部形状の造形が可能である．しかし，層を積み重ねるという造形手法から積層方向への引張強度が低い問題を抱えている．特に，異なる特性を持つ材料同士の接合強度の低さが問題となっている．本研究では，異種材料を用いた3次元モデルの造形工程に機器による接合面への表面処理を含む造形実験を実施し，引張強度への影響を定量的に評価する．</p>

DOI： 10.11522/pscjspe.2018s.0_397

One Action Press Forming of Helix Bevel Gear by Using Multi-Cylinder Press and Die Heating System Reviewed

Nakamura Katsuaki, Koresawa Hiroshi, Narahara Hiroyuki

International Journal of Automation Technology ( Fuji Technology Press Ltd. ) 12 ( 5 ) 767 - 774 2018.01

Language：English Publishing type：Research paper (scientific journal)

<p>In the case of a complex shaped helix bevel gear, the forging of complete gear tips is very difficult to achieve. In almost all cases, tooth profile is finished by cutting machine from simple shaped forged parts, therefore requiring considerable machining time and cost. However, there are many approaches to forging. Forging is mainly classified as hot and cold forging, and uses a single motion press. In the case of hot forging takeoff of products from die is difficult by the cooling shrinkage from die and accuracy of products is lower level than cold forging. In addition, in the case of cold forging, a complicated shape is difficult to achieve based on the lack of ductility of the materials. To realize a helix bevel gear using a single forging operation, we applied a tool heating system and three-axis forging press. The tool heating system is applied to prevent a temperature decrease in the material by contact between the tool and forging material during the forging process. Further, to optimize the forging direction and timing, we used a three-axis forging press. We confirmed good forging capability of this special forging process, as well as the high precision of the forged parts. Moreover, through the thermo-mechanical control of steel and the tool temperature, the forged parts showed good mechanical properties, such as high hardness.</p>

DOI： 10.20965/ijat.2018.p0767

Other Link： https://ci.nii.ac.jp/naid/130007472300

３次元金属積層造形におけるレーザ焼結プロセスの可視化と高機能金型製造への応用

楢原弘之

天田財団助成研究成果報告書 ( 公益財団法人天田財団 ) 31 ( 0 ) 69 - 74 2018.01

金属光造形複合加工法による金型製造 : 産業用金属3Dプリンターの産業応用への課題

楢原弘之

光アライアンス 28 ( 12 ) 48 - 52 2017.12

産業用3Dプリンタと電子ビーム表面処理によるモールドデポジット抑制とガス排出機構の研究

是澤宏之, 楢原弘之

型技術 32 ( 5 ) 44 - 47 2017.05

W-12 Developing a Kit for Experiential Understanding of Elastic and Plastic Properties of Materials in Class Reviewed

ARIMOTO Kyozo, FREDRIKSSON Claes, SILVA Arlindo, NARAHARA Hiroyuki

JSEE Annual Conference International Session Proceedings ( Japanese Society for Engineering Education ) 2017 ( 0 ) 71 - 76 2017.01

Language：English Publishing type：Research paper (scientific journal)

Elastic and plastic properties of various materials, generally measured by dedicated testing machines, constitute an important area of engineering education. It is therefore desirable that students understand this topic, not only numerically, but also experientially. Classic research has shown that the ratio of Young’s modulus and yield strength relates to so called springback phenomena in long and thin objects. This topic is the basis for the development of a kit for classroom activities, including different metal wires and bending templates, a card and two arbores. Students bend wires by hand, using the templates, and use individual moments applied to the wires to investigate springback. In this paper, the result of a collaboration involving experimental equipment design, engineering educators and software developers is described. It outlines the theoretical background, experimental procedure and equipment needed as well as how to compare lab results to data in visual Ashby charts for increased understanding.

DOI： 10.20549/jseeen.2017.0_71

Other Link： https://ci.nii.ac.jp/naid/130006318391

Enhancement of Electrically Conductive FDM Parts Adhesion Strength to Different Polymers through Atmospheric Pressure Plasma Treatment

Copetti Rodriguez Ciro, Narahara Hiroyuki, Koresawa Hiroshi, Nakatani Hisayuki, Shimizu Akimitsu

Proceedings of JSPE Semestrial Meeting ( The Japan Society for Precision Engineering ) 2017 ( 0 ) 1025 - 1026 2017.01

Authorship：Corresponding author Language：English Publishing type：Research paper (conference, symposium, etc.)

Multi-material 3D printing has been a hot topic among many papers and the final goal for many manufacturers and developers. However, one of the main issues holding multi-material printing back is the affinity between different materials and consequently the low strength of the resulting parts. This proceeding discusses the results of atmospheric-pressure plasma incidence on adhesion strength between different polymers commonly used in FDM applications and electrically conductive PLA. Strength test samples were manufactured with the aid of an adapted Delta printer set-up, capable of executing multiple activities in tandem with the print job. Surface free-energy analysis and strength tests were carried out for untreated and treated parts with alternating deposition orders and the results analyzed. Finally, the results were compared with observations already present in the literature and future steps for the completion of this work discussed.

DOI： 10.11522/pscjspe.2017S.0_1025

Other Link： https://ci.nii.ac.jp/naid/130006043553

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