Enhanced dry machinability of honeycomb‐reinforced ablative thermal protection composites by longitudinal ultrasonic‐assisted milling

Honeycomb‐reinforced ablation thermal protection (HRATP) composites are widely used in aircraft thermal protection systems as one of the most effective thermal protection methods. The conventional milling (CM) method renders it susceptible to various processing damages, which directly affects the bonding strength of the whole component. Aiming at the poor surface quality caused by the large cutting force in the cutting process, a longitudinal ultrasonic‐assisted milling (LUAM) method was proposed, which realized the periodic separation of multi‐edge micro‐tooth milling cutter and workpiece, effectively reduced the cutting force and improved the surface quality. A motion trajectory model for a multi‐edge micro‐tooth milling cutter was developed, and an experimental study of LUAM was conducted. The effects of different tools and ultrasonic characterization parameters on cutting force, cutting temperature, and surface quality were compared and analyzed. The results of the comparison between the four different tools indicate that the multi‐edge micro‐tooth milling cutter exhibits the highest machining quality. Compared with CM, applying longitudinal ultrasonic vibration to the multi‐edge micro‐tooth milling cutter reduces the inlet burr length by 33.3%, and the chip was mainly removed in a small particle manner. Highlights A multi‐edge micro‐tooth LUAM model was established of HRATP composites. Sensitivity analysis of milling and vibration parameters on temperature. LUAM reduces the cutting temperature by 12.4% and the burr by 33.3%. LUAM significantly enhanced the surface quality compared with CM.