Numerical and experimental investigation on flow field during fixed abrasive lapping for structural optimization of lapping tool

Owing to its superior machining efficiency and precision, fixed abrasive lapping is considered as a promising technology in ultra-precision machining, with demonstrated success across diverse material systems including metals, ceramics, semiconductors, and beyond. The flow characteristics of slurry in contact area between workpiece and tool play an important role in maintaining stability of workpiece temperature and promoting rapid removal of debris. To enhance material removal performance and surface quality of 4H-SiC lapping process, computational fluid dynamics simulations and experimental studies of flow field on fixed abrasive pad surface were conducted with aim of designing a novel structure. The effects of groove structure and size parameters on flow field and velocity distribution were investigated through a series of simulation analyses. Furthermore, the distributed scatter point methods were applied to simulation results, and the flow velocity uniformity was employed to quantitatively evaluate flow field characteristics. The liquid phase and flow velocity distribution under different groove structures and different groove widths are compared and discussed. Relevant experiments were designed to verify simulation results, and lapping effect of fixed abrasive pad was analyzed. The results show that hexagonal structure fixed abrasive pad has better flow characteristics than concentric radial and circular. In this experiment, when fixed abrasive pad speed is 60 r/min, the surface roughness of SiC machined by hexagonal structure fixed abrasive pad reaches 2.4 nm, which corresponds to the flow velocity uniformity value predicted by the simulation results at 60 r/min. The surface accuracy of workpiece machined by fixed abrasive pad can reach submicron level.