Model establishment of surface roughness and experimental investigation on magnetorheological finishing for polishing the internal surface of titanium alloy tubes

A novel magnetorheological polishing process is devised to polish the internal surface of titanium alloy tubes. Under the magnetic field in polishing area between the internal surface of tube and polishing head, magnetorheological polishing fluid gets stiffened and acts as the polishing tool. In this process, rotation motion of tube and reciprocating linear motion of polishing head are carried out simultaneously resulting in helical motion trajectory of abrasive particles on workpiece surface. The finishing forces during magnetorheological polishing process including normal indentation force and shear force are analyzed and modeled. Based on the proposed model, final surface roughness Ra model is proposed to predict the polishing performance. Experiments are carried out to investigate the effect of polishing time and initial surface roughness Ra on polishing performance. The experimental results are compared with the model results, which are highly consistent. The results show a gradual growth of surface precision with polishing time and an augment of polishing efficiency with increasing initial surface roughness Ra.