Simulation and experimental study on polishing of spherical steel by non-Newtonian fluids

Abstract

Shear thickening fluid polishing (STFP) is one type of the non-Newtonian fluids which is used to polish the complex shapes. This method is applied to machine the spherical hardened steel in this study. The principle and performance of STFP was introduced. There are many parameters that significantly influence the STFP process; however, the inclination angle of the workpieces is one of the parameters that greatly affect the pressure distribution and deviation of surface roughness at different area on the workpiece surfaces. The effect of inclination angle, fluid viscosity, and polishing speed to the machining process is carried out by simulating. The inclination angle parameters of the workpieces such as 0°, 3°, 5°, 7°, 10°, 12°, and 15° are used during the simulation and experimental process. The distributed pressure area and polishing fluid flow characteristics will be presented and analyzed. Simulation results show that the inclination angle of 5° and fluid viscosity of 3 Pa.s are the best combination. The pressure area is distributed throughout all the surface of the spherical steel and maximum pressure value is achieved about 9.29 Pa in the case of 5° inclination angle. In addition, experimental results illustrated that the surface roughness achieved is the smallest when inclination angle of 5°, the fluid viscosity of 3 Pa.s, and polishing speed of 100 rpm. The best surface roughness can be reach 12 nm after 15 min polishing. The deviation of surface roughness is about 14 nm in this case. This result agrees well with simulation results. The simulation and experimental results show that STFP was a promising and feasible processing method in the polishing of workpieces with complex shape.