By a rotary electrode, WC-Co cemented carbide i s machined under low voltage (not exceeding 100 volts) and the machinability is compared by using the dielectric liquid such as kerosene or service city water. The results are as follows:
(1) The maximum value of the discharge current in water is lower than the one in kerosene under the same electrical condition.
(2) In water the electrode wear rate is lower and also the stock removal rate becomes larger than in kerosene when the source voltage increases or the charging resistance decreases.
(3) The electrolytic action is recognized in water (specific resistance: 10
3-10
4Ωcm) and it influences both the removal rate and the machining accuracy.
(4) In water the surface roughness is smaller and then the machining accuracy becomes lower than in kerosene. When using the isolated electrode in water, the accuracy is remarkably improved.
View full abstract