Finishing Characteristics of Magnetorheological Shear Thickening Finishing for Titanium Alloy Using Multi-pole Rotating Magnetic Field

This work aims to explore the finishing characteristics of magnetorheological shear thickening finishing for titanium alloy (Ti-6Al-4V) using multi-pole rotating magnetic field. Multi-pole rotating magnetic fields with different magnetic pole arrangements were designed. The magnetic field characteristics under three magnetic pole arrangements of N-S-N, N-S-N-S and N-S were analyzed based on simulation approaches and experimental measurements. Experimental setup for the surface finishing of titanium alloy (Ti-6Al-4V) was established to investigate the influence of the magnetic pole arrangement, spindle speed, rotary table speed and working gap on the surface roughness of the workpiece. Comparative analysis of the surface micro-topography before and after finishing was conducted based on scanning electron microscope. A large magnetic field intensity and a large number of closed loops of magnetic field lines were obtained in the finishing region under the N-S-N magnetic pole arrangement, which led to form more rigid and a large number of magnetic brushes under the employed magnetic field action. It was observed from the experimental results that the N-S-N magnetic pole arrangement exhibited a good finishing efficiency. The developed finishing media was effective for surface finishing of titanium alloy (Ti-6Al-4V). The surface roughness of 67 nm was achieved from the initial value of 1.2 μm, which improved by over 94%, under the experimental conditions of the N-S-N magnetic pole arrangement, spindle speed of 600 r/min, rotary table speed of 160 r/min, and working gap of 0.7 mm. Surface observations showed that a smooth surface without obvious scratches was obtained. The surface quality was significantly improved. The cutting marks were left on the finished surface because of the scratch of abrasive particles. Regulating the magnetic pole arrangement of multi-pole rotating magnetic field can effectively control the photofinishing processing efficiency, and with the optimization of magnetic shear-thickening photofinishing media and processing process parameters, the surface of titanium alloy can achieve nano-level photofinishing and significant improvement of surface quality. © 2021, Chongqing Wujiu Periodicals Press. All rights reserved.