Modelling of Temperature Field and Stress–Strain State of the Workpiece with Plasma Coatings during Surface Grinding

Abstract

Plasma coatings play a key role in surface tailoring through providing important advantages for tools during their further application. However, grinding these coatings may cause different defects such as grinding burns and cracks, structural changes to the coating material, and the destruction of adhesive contacts between the coating layer and the substrate. The reason for that is the high heat flux generated in the process of abrasive material removal due to the high friction and stresses. In order to define the optimal conditions for grinding plasma coatings, the mathematical model of the temperature thermal field and the stress–strain state during the grinding process is developed. Based on the temperature, strength, and fracture criteria, this mathematical model makes it possible to define the functional relationship between the technological characteristics of the grinding process and the conditions that provide the required quality of surface processing. The role of the structural defects that are generated while coatings are being sprayed, as well as during coating adhesion, is also considered. An algorithm developed to present the results of the modelling process enables checking if the input parameters meet the condition of zero-defect grinding of a workpiece, and determining an expected surface roughness. Input parameters include the grinding wheel geometry, its abrasive properties, the wheel speed, longitudinal and transverse motion, grinding depth, and the use of the cutting fluid. Experimental testing of this study shows the way in which the regime of the grinding process and different grinding wheel parameters influence the physical and mechanical properties of the surface layer.