The tool wear analysis on the multilayer coated carbide inserts in turning and milling of AISI 1045 steels was performed using advanced microscope and image processing techniques. In turning process, the flank wear evolution, surface roughness and groove sizes on the coating layers were analyzed to understand the flank wear mechanism(s) involved. The dominant wear phenomenon was abrasion and, after carbide was exposed, adhesion took over. For flank wear prediction, 2-body abrasion model was used along the interface conditions from finite element (FE) model, which provides the temperature on the cutting tool. In a face milling study, multilayer cutting tools, double (TiN/TiAlN) and triple (TiN/Al2O3/TiCN) layered coated carbide, processed by physical vapor deposition (PVD) and chemical vapor deposition (CVD) respectively, were evaluated in terms of various cutting conditions. Similar to the turning case, abrasion was found to be the most dominant tool wear mechanism in milling. Edge chipping and micro-fracture were the tool failure modes. Overall, the double layer coating was superior to the triple layer coating under various cutting conditions due to the benefit coming from the coating deposition processes themselves. On the other hand, drilling of carbon fiber reinforced polymer (CFRP)/titanium (Ti) stacks has been performed using carbide and PCD drills. The dominant wear mechanism for carbide tools was the abrasion by fibers in CFRP drilling and Ti adhesion, covering entire cutting edge while the main wear behavior of PCD drill was edge chipping. The adhesion of titanium seems to be the most important factor in tool wear and micro-chipping because the adhered titanium seems to be brushed away by the fibers in CFRP when drilling the composites, which accelerates tool wear in drilling of stacks. PCD drills have more wear resistance than carbide drills only in terms of the flank wear land. However, due to the inherent brittleness of PCD drills, chipping was observed at the tool edge when drilling titanium. Finally, for a better understanding of Minimum Quantity Lubrication (MQL) and its effective use in practical industrial applications, MQL parameters such as droplet sizes, the droplet distributions and wetting angles of various types of lubricants were investigated. The measurement method of droplet size and distribution was proposed using confocal laser scanning microscopy (CLSM) and wavelet transform. In addition, the empirical droplet size estimation equation was also introduced for extremely small droplets, which are difficult to be measured. The distribution of the droplets has been also studied to determine the MQL optimal nozzle-workpiece distance and the nozzle discharge pressure. To extent the applicability of MQL to more aggressive machining conditions, a potential additive to MQL lubricant, which is a mixture of exfoliated nano-graphene particles and vegetable oil, have developed. Oil based lubricant, especially nano-enhanced vegetable oil, showed a better wettablility and tribological behavior. MQL-ball milling tests with nano-graphene enhanced lubricant were performed to show a remarkable performance improvement in reducing both central wear and flank wear as well as edge chipping.
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