Local tool wear profiles prediction using physics-based models

A semi-empirical model based on the physics of the wear mechanisms is developed to predict crater profiles of multilayer coated tools after turning. The averaged dissolution and abrasion relationships are recast into local versions to predict directly based on the temperature and pressure profiles from Finite Element (FE) simulations. The approach is reasonable to explain the crater profiles observed in multilayer coated carbides. However, the model deviates from the real profiles due to the kappa-to-alpha-Al2O 3 phase transformation in the middle layer, the change in interfacial conditions with the exposure of subsequent layers, the combined wear resistance of multi-layers of the cutting tool, and the deformation of the cutting tool.;In addition to the modeling effort, AlSI 1045 steel bars were dry-turned with multilayer coated carbide tools. The worn cutting tool tips were analyzed by means of Secondary Electrons (SE) imaging, Back-scattered Electrons(BSE) imaging, Energy Dispersive x-ray Spectroscopy (EDS), X-ray Diffractometry (XRD), Profilometry, and Confocal Laser Scanning Microscopy (CSLM).;The existence of two layers made of different Al2O3 polymorphs (kappa and alpha) in the fresh inserts was demonstrated with XRD analysis and SE imaging. SP and CSLM were extensively used to characterize the surface topography of the worn rake faces. In doing so, the tool tip deformation was observed taking place and influencing the crater patterns measurements. On the other hand, the work material microstructure showed a clear influence in the amount of wear obtained. Two nominally equal AlSI1045 steels with normalized and grain-refined microstructures gave very different wear losses under the same machining conditions.;The multi-resolution wavelet analysis was successfully tailored to postprocess the surface data. Very clear wear trends, not available with traditional Fourier-based filters, were identified. The latter aided in the determination of wear coefficients and in the unambiguous detection of the maximum crater depth location. Additionally, the feasibility of roughness separation from waviness and form in the crater zone was proven, which opens a promising path for future micro-mechanisms analysis.