Comparative analyses of damages formation mechanisms for novel drills based on a new drill-induced damages analytical model

摘要

During CFRP drilling, exit damages such as burrs and delamination frequently occur. There is a critical thrust force below which the delamination can be avoided. But the concrete formation mechanisms of the delamination and the burrs can't be obtained based on these existing models. A novel analytical model is presented to analyze systematically the drilling performance of the novel drill structure. The result indicates that the critical thrust forces at different theta are different and reach the maximum values when theta = 0 degrees and theta = 180 degrees. Compared with the WC drills, the PCD drills have extreme advantage to reduce the damages. There are four high risk burrs occurrence zones for plain-woven CFRP. The candle stick edge of the linear structure is more suitable for the drilling of CFRP. And the increase of the 2nd counterboring edge length will be favorable for reducing the delamination.