Research on chip mechanism of Inconel 718 with ultrasonic assisted drilling by step drill

Nickel-based high-temperature alloys (Inconel 718) are considered to be difficult-to-machine materials with high yield strength and properties widely used in the aerospace industry. Due low thermal conductivity of Inconel 718 material, it leads severe machining hardening easy cause tool wear. In this paper, three step drills different second point angles proposed, thrust force torque models twist drill bits established, then critical burr generating states analyzed. The experimental finite element simulation analyses four showed that force, torque, burr, effective stress, chip flow rate generated by under conventional drilling conditions were less than those drill. decrease as angle decreases. smaller drill, higher rate, lower maximum stress better quality. addition, is compared (CD) ultrasonic-assisted (UAD) analyze differences temperature morphology, results show breaking performance drilling.