Trajectory uniformity in fixed abrasive plane lapping of BK7 glass

To improve the surface accuracy of fixed abrasive plane lapping, a reciprocating swing lapping (RSL) method combined with an irrational rotational speed ratio was proposed. The kinematic models of traditional lapping (TL) and RSL were established based on the coordinate transformation method. The effects of the rotational speed ratio on the single abrasive trajectory, sliding distance distribution, and wear distribution of the lapping pad were studied by numerical simulation. Furthermore, lapping uniformity was evaluated by regional meshing and statistical methods, and the coefficient of variation (CV) was employed as the quantitative evaluation index. Finally, a comparative experiment of TL and RSL was conducted. Results showed that the abrasive trajectories in TL were periodically distributed, and there was an obvious ring texture feature on the workpiece surface, while the abrasive trajectories in RSL were disordered, which could effectively restrain the annular kinematic characteristics of the workpiece surface. At the same rotational speed ratio, the abrasives' sliding distance distribution and the wear uniformity of the lapping pad in RSL were always better than TL, and the irrational rotational speed ratio helped ameliorate the lapping performance. The experiment results were consistent with the simulation rules, which verified the superiority of RSL combined with an irrational rotational speed ratio.