Study on Serrated Chip Formation of Aluminum Alloy 7050-T7451 in Ultra-high-Speed Cutting

In this paper, aluminum alloy (AA) 7050-T7451 was taken as the research object and the high-speed right-angle cutting simulation model was adopted to simulate the cutting process under different cutting speeds (1000-4000 m/min) and feed rates. Besides, the chip formation law was analyzed under different cutting parameters. The simulation results were validated by experiments and it showed that simulation had high reliability. Moreover, the chip formation was predicted by ultra-high-speed (4000-6000 m/min) cutting simulation. It was discovered that the sawtooth degree and sawtooth frequency increased with the increase of cutting speed. When cutting speed was 1000-4000 m/min, the sawtooth degree increased with the increase of feed rate. However, when cutting speed exceeded 2513 m/min, the sawtooth degree was affected by cutting thickness, which made the sawtooth degree decrease with the increase of feed rate. The critical cutting speed of serrated chip formation was 1257 m/min. When the critical speed reached 6000 m/min, the sawtooth degree was close to 1. The chip shape changed from serrated to cracked, it implied that the chip transformed from plastic to brittle under this speed.