Improvement of PVD coated inserts cutting performance, through appropriate mechanical treatments of substrate and coating surface

The wear behavior of coated cemented carbides (HM) inserts with various substrate and coating surface mechanical treatments were investigated experimentally in milling and analytically through a finite-elements method (FEM) simulation of the cutting process. The treatments carried out were polishing and micro- and glass-blasting at various pressures. The initiation and progress of the tool failure was depicted through scanning electron microscopy (SEM) and energy-dispersive X-ray microspectral investigations of the cutting edges used. Furthermore, FEM simulation of the contact between the tool and the workpiece enabled the development of a quantitative description of the influence of the substrate and coating surface roughness on the mechanical stresses occurring, and thus on fatigue-induced coating failure and wear. The coating stress-strain curves and their fatigue endurance were determined through FEM-supported nanoindentation measurements and impact test result evaluations, respectively. In all FEM calculations conducted, multilinear constitutive laws were applied for modeling the coating and the substrate. The experimental and computational results obtained quantitatively exhibit the influence of the substrate, as well as of the coating surface treatments, on the cutting performance of the HM insert. (C) 2001 Elsevier Science B.V. All rights reserved.