Topographic imaging of tool wear in multilayer coated inserts

The present study deals with the confocal imaging of tool wear in multi-layer coated inserts using Confocal Laser Scanning Microscopy (CLSM) as a means to obtain the tool wear evolution in a local level.; Steady-state turning experiments were carried out on 1045 steel bars with multi-layer coated inserts consisting of TiN/Al2O3/TiCN deposited on a carbide substrate. Topographical images of the crater wear as well as orthogonal sections of the flank and crater wears as functions of machining time were obtained. After the Scanning electron microscope (SEM) image analysis a humped island of TiN coating material next to growing a crater of Al2O3 and steel traces were found. The maximum crater depth location was observed to move across the rake face with machining time. These unexpected features of crater wear seem to have their origin in the competition of the abrasive and dissolution mechanisms. Validations of the confocal results were performed using the SEM and the Atomic force microscope (AFM).