Design of Experiment for Determining Setting Parameter on Plasma Arc Machining for Stainless Steel Plate Cutting with Full Factorial Design

Plasma Arc Machining is a metal cutting where conductor metal such as sheets metal are cut with plasma arc. Problem in plasma arc machining is the result of cutting has burr which is quite large due to the heat, resulting the surface roughness on the workpiece. This research aim to minimize the surface roughness of the stainless steel plate uses a design of experiment method with full factorial design. In this research, there are three factors, that are torch height, cutting speed, and electric current. Each factor has three levels. By using full factorial design, the number of treatments are 33=27 trials. The results of the research on data processing analysis of variance show that the most influential factor on surface roughness is cutting speed with contribution value of 90.76% followed by two other factors, that is height torch with contribution value of 2.42% and electric current with contribution value of 0.23% and contribution value of noise by 6.59%. Then based on data processing robust design the optimum combination of parameters is obtained by using setting 1 mm torch height, 2400 mm/min cutting speed, and 30 A electric current. Based on the confirmation experiments, experiments with optimum parameter combinations can reach a gap noise of 2.283 dB. Therefore, the design of experiment for determining parameter setting plasma arc machining can determine the optimum combination of parameters to minimize the surface roughness.