Generating precise non-flat grinding wheel surfaces via CO2 laser ablation: Understanding the relationship between overlap rate and feed rate on composite materials

Abstract

Non-flat structures are essential features in key mechanical functional surfaces such as aero-space engine blade tenons, screw rods and machine tool guide rails etc., which usually require profile grinding as the finishing process to meet demanding working requirements. However, the precise manufacturing of profile grinding wheels remains challenging as it is hard to remove the superhard materials within the grinding wheel in a controllable way. Dressing the target wheel by laser ablation appears promising, however, the interactions between the laser energy beam and target composite materials are quite complex, especially the combined behaviours among a serial of adjacent ablation tracks are hard to understand when concerning the ever-changing Overlap Rates (ORs) and feed rates in the ablation process. In this study, the nature of the laser beam and the characteristics of the beam energy distribution are analysed. The shapes for the laser ablation under various ORs and feed rates are theoretically analysed and experimentally validated. Based on the results, empirical prediction models regarding ablation depth, width, and topography changing with ORs and feed rates are established. Finally, the possibility of manufacturing profiled grinding wheels by controlling overlap and feed rates is studied. An attempt to generate precise non-flat structures (including stepped and curved surfaces) via ablation with a CO2 laser using the developed strategies is performed, and a smooth profile with a relative error of 2.2 % is achieved without any extra focal plane change manipulations. The work provides a novel strategy for the manufacturing of complex-profile grinding wheels.