Experimental investigations on weak magnetization-enhanced force-rheological polishing of SiC mold

Abstract

To investigate the in uence of weak magnetization enhanced force rheological polishing (WMEFRP) parameters on the surface quality of small aspheric SiC mold, a magnetic shear thickening uid (MSTF) containing shear thickening uid (STF), Al 2 O 3 particles, and carbonyl iron powder particles was developed. Furthermore, the polishing characteristics and stability of the method were analyzed through rheological tests and magnetic eld simulation. Orthogonal experiments were carried out on a small aspheric SiC mold using a ve-axis machining center. The in uence of spindle speed, polishing clearance, abrasive particle size, and other factors on material removal rate (MRR), surface morphology, surface roughness (SR), and subsurface damage (SSD) depth was explored. The results showed that MRR and SSD depth increased with spindle speed, whereas SR rst decreased and then increased. Polishing clearance had a signi cant negative correlation effect on MRR, SR, and SSD depth, whereas abrasive particle size had a weak positive correlation effect on them. The parameter optimization method based on multi-objective matrix was used to evaluate the in uence weight of MRR, SR, and SSD depth on the orthogonal test results. The optimal scheme was determined as follows: the spindle speed was 720 rpm, the polishing gap was 0.5 mm, and the particle size was 3 µm. The veri cation test was carried out by using the optimal scheme. The results showed that the SR and SSD depths were considerably reduced, and the surface/subsurface quality was considerably improved. This evaluation method could meet the technical requirements of high e ciency and high surface/subsurface quality for the polishing of smallaperture aspheric SiC mold.