Selective Laser Sintering: A Case Study of Tungsten Carbide and Cobalt Powder Sintering by Pulsed Nd:YAG Laser

In the present study, tungsten carbide (WC) and cobalt (Co) powder mixture was sintered through selective laser sintering process using a pulsed Nd:YAG laser. Two different compositions of the powder mixture having 85 wt% WC + 15 wt% Co and 80 wt% WC + 20 wt% Co were used in the experiments. The optimum level of parameters, such as, composition of powder, layer thickness, hatching distance, pulse energy, pulse width and distance from focal plane were obtained by using the Taguchi method for achieving higher density, higher microhardness and minimum porosity. The Taguchi design of experiments involving an L-18 orthogonal array was followed. The effects of various sintering parameters were investigated on various responses like density, microhardness and porosity. The composition of the powder mixture and the pulse energy were found to have significant role on the microhardness. Hatching distance and cobalt percentage were the main influencing parameters on density and porosity. Surface morphology and formation of intermetallic compounds were analyzed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques.