High-efficiency ultrasonic assisted drilling of CFRP/Ti stacks under non-separation type and dry conditions

In this study, to address the low efficiency for conventional ultrasonic-assisted drilling (UAD) of carbon fiber-reinforced plastic and titanium alloy (CFRP/Ti) stacks, feasibility experiments of non-separation UAD, in which continuous cutting between the tool and the workpiece occurs at a high feed rate, are carried out. The experimental results indicate that, compared to conventional separation UAD, the non-separation UAD effectively reduces the cutting forces by 24.2% and 1.9% for CFRP stage and 22.1% and 2.6% for the Ti stage at the feed rates of 50 and 70 µm/r, respectively. Furthermore, the non-separation UAD significantly improves hole quality, including higher hole diameter accuracy, lower hole surface roughness, and less hole damage. In addition, the non-separation UAD can decrease adhesive tool wear. This study demonstrates that, compared to conventional drilling (CD), the non-separation UAD can effectively improve drilling quality and tool life while maintaining high efficiency.