Investigation of Tool Entry Strategy when Pocket Milling Titanium Alloy, Ti-6Al-4V under Wet Condition

摘要

Tool entry strategy determines how the cutting tool enters and moves into the workpiece during pocket milling operation without collision between the tool and workpiece. Optimal selection of tool entry and its parameters settings during pocket milling are crucial in order to improve the tool life and accuracy of the machined part. Pocket milling process is performed purposely to reduce the weight of the parts as it involved high material removal and generally associated with high manufacturing costs. This work aims to investigate the effect of tool entry strategies on the tool wear of TiAlN coated carbide insert when pocket milling titanium alloy, Ti-6Al-4V under wet coolant condition. Two tool entry strategies namely circular and angular ramping were evaluated under rough machining condition. Three main cutting parameters of cutting speed (Vc), feed rate (fz) and depth of cut were used with constant values at 90m/min, 0.1 mm/tooth and 2mm respectively using fixed entry angle of 3°. Tool wear was observed and recorded for both circular and angular ramping entry modes at the end of the experiment. Experimental results showed that tool flank wear increases as the number of pass or run increases. During the first run, the recorded flank wear was at 0.016mm and 0.033mm for circular and angular entries respectively. At the fifth or the last run, the recorded flank wear was 0.028mm and 0.041mm for circular and angular entries respectively. It can be clearly concluded that the best tool entry when pocket milling Ti-6Al-4V was circular ramping as compared to angular entry due to the small immersion angle and intermittent tool engagement. These phenomena made it possible to ensure better stability during machining and prolong the tool life thus reducing the machining cost and enhance the overall performance of the pocket milling process.