Surface Generation Modeling and Experimental Analysis of the Fixed Abrasive Deterministic Lapping Process

A highly efficient, controllable fixed abrasive deterministic lapping process based on the CCOS principle was proposed. Through the line lapping experiments, results indicate that the liquid central supply mode is beneficial to the improvement of process efficiency and surface quality compared with the traditional liquid supply mode. The influence of process parameters on the surface hardness after processing and the material removal mechanism of the fixed abrasive lapping was analyzed by scanning electron microscopy, in order to observe the surface topography of the workpiece after lapping. The linear relationships between the material removal rate and tool speed, load, time were verified by line lapping experiments with different parameters. Results reveal that the material removal process of the fixed abrasive lapping process conforms to the convolution iteration principle of CCOS. A simulation model of the surface topography of the fixed abrasive lapping pad was established based on the unit cell theory and the assumption of uniform abrasive particle size. At the same time, the effect of parameters, such as the size and concentration of the abrasive particles and the shape of the lapping pad, were considered in the model. Based on the simulation data of fixed abrasive lapping pad topography, the calculation model of the contact gap between the lapping pad and the workpiece was established based on the removal mechanism of the hard and brittle material and the micro-contact model between the lapping pad and the workpiece. This process also considered the mechanical properties of the workpiece surface under certain parameters. Furthermore, the point lapping removal spot model was established. The accuracy rates of this model under different pressures, rotation speeds, durations were verified by point lapping experiments. After dispersing continuous machining trajectories, the convolution operation relationship between the total lapping removal and the point lapping removal was established by considering the shape of the lapping pad, the size and concentration of the abrasive particles, the rotational speed and the load of the lapping tool, and the trajectory parameters. The fixed abrasive lapping surface generation model was also proposed. Plane lapping experiments and surface simulations with different parameters were carried out. Results show that the fixed abrasive deterministic lapping surface generation model can predict the lapping removal depth and the residual error of the lapping surface under different parameters. The proposed model can also improve the controllability of the fixed abrasive lapping process. © 2019, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.