Following the Integration of Diamond Particles on the Lapping-Plate Surface: Towards a More Efficient Charging Process

Even when the charging of lapping plates can extensively influence their subsequent finishing performance, the subject has been scarcely treated in specialized literature. The present paper aims to help fill such a gap and gain a better insight of the charging process. A semiquantification of the diamond particles integrated into the lapping plate surface as a function of charging time was performed by Raman spectroscopy and scanning electron microscopy, together with a simple image-analysis procedure. The corresponding evolution of surface rough features was followed from atomic force micrographs with the aid of fractal-analysis tools. It was observed that charging proceeds in two stages, both with different rates of diamond particle integration. This leads to a significant waste of diamond slurry. During the first stage, the charging ring seems to preferentially promote a further flattening of the lapping-plate surface. Diamond particles are apparently more readily incorporated into such “flattened” regions during the second stage. The results suggest a specific topographic condition must be attained before the diamond can be efficiently integrated into the lapping plate surface. A lapping-plate preconditioning step could help improve this situation and reduce the amount of abrasive waste during charging.