Tailored Cutting Fluid Supply in Additively Manufactured Milling Tools for Aerospace Applications

Abstract Machining of aerospace materials such as titanium alloys requires the use of high-pressure cutting fluid supply to minimize tool wear and maximize productivity as well as process reliability. By employing the additive manufacturing (AM) technique of Laser Powder Bed Fusion (PBF-LB), indexable cutting tools can be manufactured, including complex and individualized channel and nozzle structures for the internal cutting fluid supply. Thus, flow losses are reduced and the cutting fluid efficiently and effectively guided to the contact zone. In this work, a method for the systematic design of the internal cutting fluid supply was developed for single-row indexable milling tools, taking into account possibilities and constraints of PBF-LB. Based on this method, various cutting fluid supply variants were derived, varying in nozzle geometry, size, number and orientation. The performance of these adapted supply variants was evaluated in rough milling of Ti-6Al-4V, measuring tool wear, cutting force and chip shape. For a deeper fluid-mechanical analysis of the cutting fluid supply characteristics, CFD simulations were performed. Based on the experimental and simulation results, suitable cutting fluid supply variants could be identified, which significantly increased tool life compared to the state-of-the-art conventional tool. Especially a multitude of outlet nozzles directed on the rake face proved beneficial for increased convective cooling and reduced chip size.