強制放電分散型電解放電加工の加工特性

抄録

  In this paper, we deal with the performance of electrochemical discharge machining (ECDM) with multiple electrodes. ECDM has been used to machine grooves and holes on insulated materials such as glass. However, many cracks are often observed around a machined hole because of the accumulation of discharge heat. While some holes were being machined by ECDM on glass, the discharge current was forced to disperse by switching the electrodes to decrease the number of cracks (divided power). The performance of ECDM was compared with those of multiple electrodes connected electrically in parallel (equi-potential power) and of a single electrode. Then hole shapes were observed. The hole entrance was round because of the divided power. In the cases of equi-potential power and a single electrode, cracks were frequently generated around the hole entrance by heat expansion. The cracks were the origins of protrusions by erosion. Eventually, long protrusions were formed. Because bubbles collapse during pulse intervals because of the divided power, the hole diameter was not enlarged.