Parameter Optimization Design of Plasma Arc Machining SS 304 Alloy by Means of Probabilistic Multi – objective Optimization

Abstract

Plasma arc machining is an unconventional machining process, which is widely used to machine intricate part profiles of alloys with difficulty in general machine. In general, the surface roughness, kerf ratio, and material removal rate (MRR) are used as evaluation targets of the production process and quality of the machining samples; the plasma arc cutting parameters, such as arc voltage, standoff distance, cutting speed, and plasma offset, are employed as the input parameters for the cutting of SS 304 alloy machined at two different types of nozzles (130 A and 200 A). The parameter optimization design of plasma arc machining is a typical of optimal problem with multiple objectives. The employment of a rational multi – objective approach is quite important to the designers for the parameter optimization design of plasma arc machining. In this article, the probabilistic multi – objective optimization is utilized to conduct the parameter optimization design of plasma arc machining SS 304 alloy of thickness 6 mm, which is designed according to a mixed Taguchi design of L18 orthogonal array. The optimal parameters of plasma arc machining SS 304 alloy from the designed experiment for Nozzle 1 (130 A) are arc voltage at 136V, cutting speed of 2000mm/min, standoff distance of 2mm, and plasma offset of 2.25mm; the optimized parameters of plasma arc in machining SS 304 alloy from the designed experiment for Nozzle 2 (200 A) are arc voltage at 133V, cutting speed of 2000 mm/min, standoff distance of 2 mm, and plasma offset of 1.25mm. The results indicate the reasonability of the approach.