Investigation of Selected Cooling Techniques for Milling of Ti-6Al-4V

Weight and space limitations in aerospace industries have led to an interest in the application of titanium in aircraft structures and aircraft engines. Titanium’s low thermal conductivity, segmentation of the chips and extreme reactivity at high temperatures cause a focused heat load on the cutting edge. These properties give titanium its characteristic of being difficult to machine, particularly when high performance machining parameters dictate elevated cutting speeds. This leaves the need to investigate cooling strategies to maintain or improve tool life. The reduction of chip/tool contact area and time leads to a decreased heat transfer and tool wear. In this work the application of external compressed air jet cooling (dry cutting), flood cooling and focused high pressure internal cooling strategies are studied. An investigation of the benefits under finishing operations, typically used for thin wall components, is conducted to determine the advantages of the cooling techniques under each respective cooling strategy. The main evaluating parameter is the flank face wear, which is measured optically. The measurements give an indication of the performance of the respective cooling technique. In the presented paper the experimental results are analysed and discussed.