The Grey Theory Combining the Taguchi Method for the Best Parameters: A Case Study of Polishing M300 Steel

M300 steel, as high-chromium alloy steel with strong wear resistance and corrosion resistance, is widely used in the manufacture of complex profile molds and aerospace military equipment such as missile parts. However, there are still some problems such as the contradiction between productivity and surface quality in the polishing process for M300 steel. Therefore, in order to solve these problems, surface polishing experiments on M300 steel, single-factor and orthogonal experiments, and parameters’ optimization were studied. In this paper, orthogonal experiments are conducted for four selected machining parameters: grain size (A), grinding speed (B), cutting depth (C), and feed rate (D) on a grinding machine. The experiment and parameters’ optimization of the ball type abrasive tool polishing M300 were investigated by a five-axis machining center, electronic analytical balance, and three-dimensional surface topographer, and the optimal process parameters and preferred intervals were optimized. The optimal parametric condition obtained for simultaneous minimization of surface roughness (Ra) and maximization of material removal rate (MRR) is as follows: grain size=#320, grinding speed=4500 r/min, cutting depth=0.4 mm, and feed rate=80 mm/s. The above parametric combination has been validated by confirmatory tests.