Abstract: During the wire electrical discharge machining (WEDM) process, a large number of discharge pits and recast layers are easily generated on the surface of the workpiece, resulting in high surface roughness of the workpiece. To solve this problem, a discharge forming cutting-electrochemical combined machining (DFCEM) method of single crystalline silicon is proposed. On the same processing equipment, first, single crystal silicon is cut by using discharge forming cutting method. Second, the electrochemical anode reaction technology is used to dissolve the discharge pits and the recast layer on the single crystalline silicon surface. On the basis of analyzing the machining mechanism of the machining process, the Faraday’s law and the electric double layer model are introduced to establish a physical model of the motion velocity speed of the copper foil electrode in the electrochemical anode dissolution process, and related experiments are designed to verify the theoretical model. The experimental results show that DFCEM can effectively eliminate the electric discharge pits and recast layer on the surface of the single crystalline silicon caused by electric discharge cutting, thereby reducing the surface roughness of the workpiece.

Key words: electric discharge machining, discharge cutting machining, electrochemical machining, anodic reaction, modeling