Experimental study on improving silicon crystal discharge cutting efficiency based on laser irradiation method

The contact barrier formed between a metal and crystalline silicon during wire electrical discharge machining (wire-EDM) hinders improvements in the processing efficiency; thus, this paper proposes a workpiece pretreatment method that increases the doping concentration of the crystalline silicon surface. First, a silver layer was coated on a silicon surface by silk screen printing, then a laser marking machine was used to irradiate the coating surface. The mechanism of this method to form a heavily-doped layer was analyzed, and the current-voltage (I–V) characteristic curves under different pretreatment processes were compared. Finally, the influence of this method on the machining performance was studied by wire-EDM experiments. The results showed that the doping concentration of the silicon surface increased, and the contact resistance decreased. When the open voltage was 120 V, the cutting efficiency of the workpiece treated with laser irradiation and screen printing was 60% higher than that without pretreatment, and it was 28% higher than the workpiece with only the metal coating treatment; however, the treatment method had little effect on the kerf width or surface roughness. It is hoped that this work will provide useful guidance for improving the EDM efficiency of crystalline silicon.