Comparative study between wear of uncoated and TiAlN-coated carbide tools in milling of Ti6Al4V

As is recognized widely, tool wear is a major problem in the machining of difficult-to-cut titanium alloys. Therefore, it is of significant interest and importance to understand and determine quantitatively and qualitatively tool wear evolution and the underlying wear mechanisms. The main aim of this paper is to investigate and analyse wear, wear mechanisms and surface and chip generation of uncoated and TiAlN-coated carbide tools in a dry milling of Ti6Al4V alloys. The quantitative flank wear and roughness were measured and recorded. Optical and scanning electron microscopy (SEM) observations of the tool cutting edge, machined surface and chips were conducted. The results show that the TiAlN-coated tool exhibits an approximately 44% longer tool life than the uncoated tool at a cutting distance of 16 m. A more regular progressive abrasion between the flank face of the tool and the workpiece is found to be the underlying wear mechanism. The TiAlN-coated tool generates a smooth machined surface with 31% lower roughness than the uncoated tool. As is expected, both tools generate serrated chips. However, the burnt chips with blue color are noticed for the uncoated tool as the cutting continues further. The results are shown to be consistent with observation of other researchers, and further imply that coated tools with appropriate combinations of cutting parameters would be able to increase the tool life in cutting of titanium alloys

High-pressure water-jet-assisted machining of Ti555-3 titanium alloy: investigation of tool wear mechanisms

The main objective of this study is to investigate uncoated tungsten carbide tool wear mechanisms for high-pressure waterjet machining of the Ti555-3 titanium alloy. A comparative study has been undertaken (i.e. conventional versus assisted machining) based on numerous experimental tests. These tests have been accompanied by the measurement of the cutting forces and flank wear. It is concluded that the high-pressure water-jet assistance can greatly increase tool life compared to conventional machining, for all cutting conditions. The gain in tool life depends on the severity of the cutting condition. The analyses performed for each test (i.e. SEM, EDS and 3D profilometer) made it possible to monitor the tool wear and to investigate the main wear mechanisms. Based on these analyses, adhesion wear appears to be the most influential mechanism and it is accelerated by an increase in water-jet pressure. Monitoring of the wear profile made it possible to study the evolution of crater wear and material chipping during machining