Processing factors of controllable die-sinking ablation processing on Ti-6Al-4V

To achieve a controllable and stable ablation process of Ti-6AL-4V that avoids the explosion induced by the violent oxidation combustion reaction that occurs between Ti-6Al-4V and the pure oxygen medium, a mixed medium composed of oxygen and argon is proposed as the discharge medium for the Ti-6Al-4V Die-sinking ablation processing. Oxygen concentration, gas pressure and discharge energy are the research objects of this study. These factors affect the high efficiency ablation process and the explosion of the Ti-6Al-4V, and we analyzed them by establishing a diffusion model of oxygen to matrix material in the ablation process, the discharge heat source model and the theoretical derivation. We then proved this theory by experiment. Experimental results indicated that the proper reduction of oxygen concentration, gas pressure, and discharge energy can achieve a stable high-efficiency ablation process for the Ti-6Al-4V and avoid the occurrence of the explosive phenomenon. The argon medium slows the oxygen diffusion velocity, improving the discharge status and reducing the micro-crack width of the recast layer. At the same experimental conditions, the machining efficiency is nearly 9 times than that of the EDM with air medium and the ablation process type-hole depth was three times that of EDM in water.