Clarification of electrical machining phenomena by direct observation of working gap through transparent electrodes

2015 Fiscal Year Final Research Report

• Project/Area Number: 25630020
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Production engineering/Processing studies
• Research Institution: The University of Tokyo
• Principal Investigator: Kunieda Masanori 東京大学, 工学(系)研究科(研究院), 教授 (90178012)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 放電加工 / 電解加工 / 透明体電極 / 可視化 / 高速度ビデオカメラ / 加工現象 / 加工液 / 気泡

Outline of Final Research Achievements

Using optically transparent and electrically conductive electrodes made of SiC or Ga2O3 single crystals as the electrode material, the working gap phenomena of electrical discharge machining (EDM) and electrochemical machining (ECM) were observed directly. The probabilities of discharge occurrence in bubble and dielectric liquid, and at their boundaries were investigated. Relationship between the locations of discharges which occur successively was obtained to elucidate its influence on the machining stability. Furthermore, it was found that the limit of pulse duration within which machining can be performed without boiling of the electrolyte is around 5ms. Jetting the electrolyte into the gap from the hollow space of the pipe electrode may cause cabitation, resulting in deteriorated machining accuracy. Rotation of the electrode may cause concentration of bubbles at the center of rotation due to centrifugal force, thereby workpiece is left unmachined at the center.

Free Research Field

電気加工