In this study, 2D finite element modeling was applied to simulate the diamond coating tool stresses from the deposition to subsequent machining. For deposition-induced residual stresses, structural analysis with thermal strains included was conducted using linear-elastic material models. Variable thermal boundaries conditions in depositions were also considered to assess the “hot-spot” effects. For tool stresses modified by machining, first, cutting variables such as cutting forces were obtained from cutting simulations, and further used to calculate the contact loading at the tool rake. Next, transient heat conduction was carried out and a structural analysis continued, carrying final temperatures from the thermal analysis and initial stresses from the depositions. The final stress distributions were then attained and interfacial stresses around the cutting edge were analyzed.

The results can be summarized as follows. Deposition-stress concentrations are significant around the cutting edge and sensitive to the edge radius. Nanocrystalline diamond coating tools have a lower elasticity leading to smaller deposition stresses compared to conventional CVD diamond coatings. With machining loading added, stress evolutions around the tool tip are mainly caused by the thermal load, leading to stress reversals. Consequently, the cutting speed dominates the stress reversal which is possibly related to delamination wear. Increasing the edge radius will lower the deposition stress concentrations around the edge area. However, large edge radii will intensify the machining contact loads due to the size effects.