Investigation of effects of coating material and cutting conditions on machinability of Ti6Al4V alloy in micro-milling process

In this study in micro-milling; the effects of coating material, cutting parameters and different cooling/lubrication conditions on burr diameter, surface quality and tool wear were investigated. For this purpose, Ti6Al4V which has a wide application in aviation and biomedical applications was choosen as workpiece. In this work, three different coating materials (TiN, AlCrN, NCD) were used and burr formation in ducts that were formed after micro-milling was determined by using 3D profilometer. The effects of coated tools on slot surface quality and types of damages on tools were also determined. According to the results; it can be concluded that, the tools coated with TiN, AlCrN, NCD decrease burr formation. At the same time, it was observed that coated tools used in this study have a big effect on tool wear. Especially in micro-milling experiments that were done by using tools coated with TiN and AlCrN, the decrease in tool diameter due to tool wear was at minimum level. However, in experiments that were done by using NCD coated and uncoated tools, decrease in tool diameter was at higher levels. Besides, it was observed that; the use of MQL brings important advantages about tool lifetime and burr formation.