Kinematics and trajectory analysis of swinging fixed abrasive plane lapping: Effect of swinging mode on the lapping uniformity

Abstract

The relative motion between the workpiece and the fixed abrasive pad (FAP) determines the abrasive trajectories and the distribution of abrasives' sliding distance (ASD), and further affects the surface accuracy of the lapping process. To improve the surface accuracy of the swinging fixed abrasive plane lapping (SFAPL), the influence of the workpiece's swinging modes on the lapping uniformity was studied in this paper. The kinematics model of SFAPL was established by the coordinate transformation method based on the kinematical principle of the crank-rocker mechanism. The numerical simulation method was adopted to investigate the abrasive trajectories and the ASD on the workpiece surface in different swinging modes. Furthermore, the regional meshing and statistical methods were applied to visualize the simulation results, and the non-uniformity coefficient (NUC) and root mean square (rms) were employed to quantitatively evaluate the lapping uniformity. Finally, the verification experiments were carried out. Results indicated that the additional swinging could avoid the periodic distribution of material removal on the workpiece surface. The swinging mode significantly affected the lapping efficiency and lapping uniformity. Compared with the traditional lapping method, the lapping uniformity was optimal when the workpiece swung out of the FAP from the bottom and inner sides, and the lapping uniformity could be improved by 44.3 %; The lapping efficiency was the highest when the workpiece swung out of the FAP from the bottom side, and the material removal rate could be increased by 45.23 %. The appropriate swinging mode should be selected based on different processing requirements in SFAPL.