无黏结相碳化钨激光氧化辅助微细铣削工艺

Binderless tungsten carbide (BTC) is an ideal material for high-temperature resistant molds, but the high hardness and low toughness characteristics lead to a poor machinability, making efficient and precise machining difficult with existing cutting methods. In order to improve the machinability of binderless tungsten carbide and achieve high-efficiency and high-quality machining of binderless tungsten carbide, a laser-oxidation-assisted micro-milling process for tungsten carbide was proposed in this study. The oxidation ablation experiments were carried out on the surface of BTC using a 1 065 nm fiber continuous laser. The effects of different laser power levels, scanning speeds, and the number of scans on the morphology of the ablation grooves were studied to analyze the oxidation mechanism of BTC. Then micro milling experiments on the oxidation grooves were carried out. Meanwhile, a control group without laser-induced oxidation process was set up for comparison with the micro milling experiments. The advantages of the laser-oxidation-assisted micro-milling process in the machining of high-hard, brittle tungsten carbide were explored. The results show that the surface of BTC showed obvious oxidation and ablation traces when the laser power was greater than 7 W. Higher power levels and the slower scanning speed lead to more intense oxidation ablation. Under the high-temperature effects of the laser, thermal cracks generated at the bottom of the grooves, and the length of the thermal cracks was reduced by multiple laser scans. The tungsten carbide grains were oxidized at high temperatures, and the oxidation product was mainly the loose WO₃. The laser oxidation process can lower the tool wear and improve the machinability of BTC.