Experimental investigation of the microhardness and surface roughness of a pressure-die-casted A413 alloy on milling using the desirability approach

Abstract

This research, focused on a newly casted A413 diesel-engine-head aluminium alloy produced under optimal casting conditions by pressure die casting, is also used for a machinability characteristics study. The experiments were methodically conducted based on a central composite face-centred design of the response surface methodology to understand the influence of milling process parameters such as cutting speed (m/min), feed rate (mm/tooth) and depth of cut (mm) on the microhardness (HV) and surface roughness (μm). The significance of the responses was validated using the analysis of variance. Multi-objective optimization using the desirability function was adopted to optimize the process parameters that simultaneously maximize the microhardness and minimize the surface roughness. The scanning electron microscopy (SEM) of the machined surface results shows that there is certain surface damage that reduces the quality of final surface components, such as scratches, feed line damage and inclusion of the tool material. Corresponding to the highest desirability, the optimal values of the process parameters were found to be 215.644 m/min for the cutting speed, 0.230 mm/tooth for the feed rate and 1.043 mm for the depth of cut.