2018 年 23 巻 p. 1-8
A lathe-type machine for electrochemical discharge machining (ECDM) has been developed for machining cylindrical parts made from insulating materials. In this paper, the removal mechanism of glass was experimentally investigated by measuring the machining forces with a two-axis force sensor during ECDM. The tangential force at an applied voltage of 40 V was larger than that at 0 V while the normal force was controlled. The amplitude of the tangential force was increased and the cycle lengthened during ECDM. Soluble and sticky sodium silicate was generated by the chemical reaction of silica glass with sodium ion. This removal process mainly caused dissolution of the sodium silicate into electrolyte.