Investigation of parameters affecting on tool wear and surface roughness in turning of Ti-6Al-4V

Machining is a manufacturing method that removes the unwanted materials over the surface of workpiece by means of cutting tool to obtain the desired piece shape. Materials having different properties take the final shape with this machining method. Especially, there are some problems in the machining of materials with excellent properties such as high strength, good corrosion resistance, long service life and low weight. The leading problem appears to be the fast wear of tool and the bad machining surface. Therefore, in this study, it was investigated that parameters have effect on tool wear and surface roughness by turning under dry cutting condition of Ti-6Al-4V alloy having excellent properties with CVD (TiCN+Al2O3+TiN) and PVD (TiAlN) cementite carbide cutting tools with the combinations of the different cutting speed, feed rate, cutting long and depth of cut. In addition, depending on cutting parameters, changes in chip thickness were investigated. Increase in feed rate, depth of cut and cutting length increased wear in both CVD and PVD coated cementite carbide cutting tool. On the other hand, increase in cutting speed increased tool wear, while surface roughness reduced to the optimum a level. Especially, with increase in feed rate and cutting length, increase in cutting speed caused the surface roughness to be worsened. The wear with PVD coated cutting tools was observed to be less than that of CVD coated cutting tools. However, the surface roughness value obtained with PVD coated cutting tools was worse when compared to CVD coated cutting tools with increase in depth of cut, feed rate and cutting length. Moreover, while chip thickness reduced with increase in cutting speed, it increased with increase in depth of cut and feed rate.