Research on N-type silicon crystal processing by liquid-immersion wire electrical discharge machining

Abstract

Passivation at the input end of N-type silicon crystals leads to a decrease in the efficiency of wire electrical discharge machining (WEDM). In response to this problem, this paper proposes a method for the liquid-immersion WEDM of N-type silicon crystals. An equivalent circuit model for the WEDM of N-type silicon crystals was established, the volt-ampere characteristics of N-type silicon crystals immersed in different liquids at the incoming end were studied, and an experimental platform for the liquid-immersion WEDM of N-type silicon crystals was established. The experimental results demonstrate that immersion in deionized water can effectively suppress the passivation phenomenon at the input end of N-type silicon crystals, thus improving the chip removal conditions between electrodes. Compared to open-loop control machining, the machining efficiency was found to increase by 42.7 % and the surface roughness was decreased by 32.8 %. After continuous machining for 1 h, the current in the machining circuit did not significantly decrease, and the machining efficiency remained unchanged.