Optimization in thermal friction drilling for SUS 304 stainless steel

The main purpose of this research is to develop a new type of thermal friction drill made of sintered carbide. In addition, to optimize the machining process of the thermal friction drilling using Taguchi method is explored. The experiments were conducted on a 30 x 30 x 2 mm SUS 304 stainless steel plate. The effects of friction angles (FA), friction contact area ratio (FCAR), feed rate (FR), and spindle speed (SS) on the two quality characteristics, surface roughness (SR) and bushing length (BL), were also investigated. After conducting all the experimental trials, the analysis procedure followed. Firstly, the significance of the four parameters on the two quality characteristics was examined by ANOVA. Then the optimal combination levels of parameters for SR and BL were determined based on the S/N ratios. Finally, confirmation experiments were conducted to verify the experimental findings. Results showed that FA and SS were the significant machining parameters that most intensively affect SR while FCAR was the only significant parameter for BL. Specially, the SR and BL were greatly improved when used in the optimized parameters settings. More importantly, the performance of the friction drill was conducted 60 runs. The thermal friction drill demonstrated a smoother, mirror-like surface and showed less wear. This proved that thermal friction drilling provided the better machining performance and longer tool life.