Research on the shear thickening polishing CaF2 with textured hollow polishing tool

Due to its excellent precision and surface quality, ultra-precision polishing has become a necessary machining technology for obtaining ultra-smooth surface. Shear thickening polishing (STP) uses the non-Newtonian shear thickening mechanisms to achieve high-precision and low-cost polishing. A kind of textured hollow polishing tool for shear thickening polishing was proposed in our work to improve the renewal rate and utilization rate of STP slurry, and the high-performance polishing to achieve the STP of Calcium fluoride (CaF2). Firstly, the preparation process of STP slurry was explored, and the influence of abrasive concentration on its rheological properties was analyzed, resulting in the determination of the optimal concentration. And on this basis, combined the computational fluid dynamics (CFD) simulation analysis, the design of textured hollow polishing tool was analyzed to study the influence of different texture structures on the flow velocity field and pressure field of the STP slurry. Secondly, the experimental platform was set up and its kinematics and material removal mechanism were analyzed. The material removal mathematical model was constructed based on Preston equation, which was then experimentally validated. The relative error between the experimental and theoretical values was 8.36 %. Finally, the interactive experiment was designed and the optimal process parameters were obtained based on response surface method (RSM) analysis. The experimental results indicated that the surface roughness of CaF2 converged to 5.9 nm, which proved the potential of the proposed textured hollow polishing tool as a promising polishing method for STP.