Investigation on the complex interaction between particle and substrate in mechanical polishing of silica glass

Abstract

Machining technology about silicate glass has been developed very fast over recent years due to the growing industrial demand of higher machining accuracy and better surface quality of optical elements while the nature of hard and brittle materials makes it difficult to acquire damage-free and ultrasmooth surface. Molecular dynamics method (MD) provides a promising approach for constructing an efficient model to describe the tool–workpiece interaction, serves as a predicting simulation tool in analyzing the complicated surface generation mechanism, and is employed in this research to study the mechanical polishing of glass and surface integrity. The results show that some particles change the substrate surface morphology by means of elastic/plastic deformation and finally being left at the top of a polished surface, and it is difficult to be removed because of the strong adhesion force. Three stages are involved in the particle adhesion process: firstly, molecular interaction force dominated the approaching stage but not contact stage; secondly, the adhesion and the resistance of deformation will gradually occupy a dominant position upon the interface adsorption and bulk deformation; and the contact area is gradually stabilized and the body deflection begins to increase and the relative stable structure is generated. A different dynamic trajectory is observed with the increasing of impacting speed and abrasive particle abruptly jumping to another point although the joint has already been generated in the initial stage.