Wet Micro-blasting Post-processing On TiN/Al₂O₃/TiCN And Al₂O₃/TiCN Coated Tools

Chemical Vapor Deposition(CVD)coated tool has the advantages of high hardness,good wear and heat resistance,which is a promising area of advanced cutting tool technology.With the increasing demands of machining difficult-to-machine materials efficiently,cutting performance of coated tools still need to be improved.As a surface modification method,micro-blasting post-process has the advantages of high efficiency and low cost,which can improve the surface morphology and increase the wear resistance of coated tools.In this paper,the CVD TiN/Al2O3/TiCN and Al2O3/TiCN coated tools have been post-processed by wet micro-blasting,with various operating parameters including blasting time,types of abrasives and diameter of abrasives.The influence of wet micro-blasting on the geometry morphology,mechanical properties and tool life.Based on the Elastic/plastic indentation damage theory,the response of coatings to the micro-blasting operating parameters has been analyzed.Face milling tests was conducted on the coated tools before and after wet micro-blast,which can be used to comprehensively evaluate the effect of the wet micro-blasting post-process.Firstly,a micro-blasting post-process device was set up.The blasting time,types and diameter of abrasives were chosen as operating parameter variables,and typical CVD coatings including TiN/Al2O3/TiCN and Al2O3/TiCN were selected.After observing the surface and geometry morphology of the CVD coated tools before and after micro-blasting,it was found that the wet micro-blasting post-process can reduce the surface roughness and remove the large particle defects on the surface of Al2O3/TiCN coatings.After Al2O3/TiCN tool coatings micro-blasted by coarse corundum abrasives for 60 s,the surface roughness decreased from 0.178 ?m to 0.082?m.When TiN/Al2O3/TiCN tool coating treated by corundum abrasives,the outermost TiN coating was prone to cracking and even peeling off,which was not suitable for strengthening after micro-blasting.The surface of Al2O3/TiCN tool coating is smoother after micro-blasting treatment,with no defects such as cracks generated.Then,three types of mechanical properties including residual stress,tribological properties and repeated impact resistance were chosen to analyze the influence of different micro blasting operating.After wet micro-blast treatment,the residual stress of TiN/Al2O3/TiCN and Al2O3/TiCN coatings are effectively increased,and the wear rates of Al2O3/TiCN tool coatings are reduced.Micro-blasting has no obvious influence on the repeated impact resistance of coatings.The mechanical property test is more convenient than the cutting test,which is useful to further understand the influence of wet micro-blasting post-process on the coated tool and provide guidance on optimizing micro-blasting operating parameters.Finally,based on the study above,tool life tests by milling was conducted to analyze the wear resistance of Al2O3/TiCN coated tools before and after wet micro-blasting.The wet micro-blasting post-process can effectively increase the tool life of Al2O3/TiCN coated tools.In particular,the operating parameter combination of zirconia abrasives with longer blasting time is most beneficial for improving the tool life.The average tool life of the Al2O3/TiCN coated tools was increased by 27.5%after micro-blasted for 60 s by zirconia abrasive.The residual stress has a positive correlation with the trend of tool life after micro-blasting.