Effect of cementite carbide tool coating type and tool radius on cutting performance

The present study represents an experimental investigation on machinability of Ti6Al4V titanium alloy by turning method. The effects of coating type (CVD and PVD coating) and cutting tool nose radius on dynamics of machining in particular the resultant cutting force and surface roughness were explored in dry cutting conditions and constant cutting depth. Cutting parameters were selected as two different cutting speed (75, 100 m/min), three different feed rate (0.15, 0.2, 0.25 mm/rev), three different nose radius (0.8, 1.2, 1.6 mm) and two different cementite carbide tool utilized (CVD and PVD coated tools) according to the literature survey and ISO 3685 standard. The components of cutting force (F_C, F_f, F_r) on cutting cementite carbide tool were measured by piezo-piezo-electric dynamometer and surface roughness measured by profilometer. It was seen that main cutting force (FC) is the most prominent constituent of the resultant force. In addition, effects of feed rate and cutting speed to the machinability were verified experimentally. Experimental results showed that physical vapor deposition (PVD) coating causes more important resultant force values compared to chemical vapor deposition (CVD) coating for the cutting speeds 75 m/min, 100 m /min and CVD coated cutting tools causes rougher surfaces compared to PVD coated tools for the same cutting speeds. Furthermore, the resultant force decreases while the tool nose radius increases for CVD coated tools and surface roughness decreases while the tool radius increases for both CVD and PVD coated cutting tools.