Estimation of residual stresses in gear form grinding using finite element analysis and experimental study based on grinding force and heat flux distribution models

Form grinding is one of the most important finishing methods to produce precision gears with high surface quality; however, the generation of high temperatures in the ground zone due to very high energy density induces a complex residual stress field during this process. In the present research, temperature distributions in the workpiece were examined using the finite element method (FEM). The heat generation process was assumed as a three-dimensional distribution of moving heat flux, and different grinding factors, including nonlinear distribution of tangential grinding force, grinding parameters, heat partition ratio along the tooth profile, and triangularly distributed heat source along the contact arc, were considered for thermal analysis. The workpiece temperature field was used as thermal loading in stress calculations, and thermal stresses were determined by thermal elastic–plastic FEM with temperature-dependent material properties and a bilinear kinematic hardening model. Further, grinding forces along the tooth profile were measured using a force dynamometer; surface temperatures were estimated by thermocouples pre-embedded along tooth profile; and surface residual stresses in both grinding direction and tooth profile direction were measured by X-ray diffraction (XRD) analysis. Experimental results of temperatures and residual stresses were utilized to validate the FEM results, and the comparison between numerical and experimental results suggests that the proposed model can be adopted to estimate residual stresses in gear form grinding.