Parametric optimization of silicon slicing using wire electro discharge machining

Silicon covers nearly about 90% of electronic sector that has made slicing a fundamental process for the manufacturing of various components such as integrated circuit, computer chips and solid-state devices. Silicon belong to the class of semi-conductor and has high brittleness due to which slicing using conventional machining processes is difficult, and many defects are to it such as chipping, scratches and large cracks. Wire Electro Discharge Machining (WEDM) is a potential process for slicing of silicon ingots. The present experimental investigation deals with the slicing of mono-crystalline silicon using WEDM process, using brass wire electrode of diameter 250 µm. The responses considered were material removal rate, surface roughness and slicing speed which were measured with the variation of the process parameters viz. open voltage(OV-V), servo voltage(SV-V), pulse on time (Ton -µs), wire tension(WT-g) and pulse off time(Toff -µs). The experimental runs were performed using Taguchi’s L27 (35) orthogonal design. The experimental results were analyzed using Taguchi based Grey Relational Analysis (TGRA) and the optimum parametric setting for the slicing was obtained at OV (111 V), Ton (0.2 µs), Toff (21 µs), WT (600 g) and SV (38 V). ANOVA analysis of the Grey Relational Grade (GRG) shows that pulse on time, wire tension and open voltage are the main contributing factor during slicing.