Improvement of Machining Characteristics of EDM by Direct Observation of Gap Phenomena using Transparent SiC Electrode

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H03899
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Production engineering/Processing studies
• Research Institution: The University of Tokyo
• Principal Investigator: Kunieda Masanori 東京大学, 大学院工学系研究科(工学部), 教授 (90178012)
• Co-Investigator(Kenkyū-buntansha): 趙 永華 東京大学, 大学院工学系研究科(工学部), 助教 (90759052)
• Co-Investigator(Renkei-kenkyūsha): HOSOE HIROTARO 株式会社放電精密加工研究所, 技術開発部, 部長 ; HARADA TAKENORI 株式会社ソディック, 放電加工機事業部, 副事業部長
• Research Collaborator: KITAMURA TOMOO 東京大学, 大学院工学系研究科, 大学院生 ; Abbas Norliana Mohd 東京大学, 大学院工学系研究科, 大学院生 ; MORI AZUMI 東京大学, 大学院工学系研究科, 大学院生 ; TACHIBANA HANAMI 東京大学, 大学院工学系研究科, 大学院生 ; YANG XIAODONG ハルビン工業大学, 機電工程学院, 教授 ; YUE XIAOMING ハルビン工業大学, 機電工程学院, 大学院生 ; ISHIKAWA ATSUSHI 東京大学, 大学院工学系研究科, 大学院生
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 放電加工 / ワイヤ放電加工 / 加工現象 / 透明体電極 / 放電点 / 気泡 / 除去メカニズム

Outline of Final Research Achievements

EDM gap phenomena were observed using transparent electrodes. Observation of single pulse discharges showed that occurrence of bumping due to superheating of the molten pool is one of the removal mechanisms. Thus, a triangular current waveform with a sharp falling of current resulted in the largest material removal among the waveforms tested. It was also found that the shear force generated by the radial flow due to the collision of the metal vapour jets from the electrodes can be another removal mechanism. It was verified by the experiment results that use of zinc, which has a lower boiling boint, as the tool electrode material showed a material removal rate higher than copper or brass. About the discharge location, discharge was more likely to occur on the periphery of the bubble generated by the previous discharge. In wire EDM, vibration of the wire electrode excited by the expansion of the bubble and the wire breakage due to concentration of discharge locations were visualized.

Free Research Field

放電加工、電解加工、微細加工、金型加工