New drilling method for damage reduction of CFRP/Ti stacks drilling

Abstract

In order to reduce the damage during drilling of CFRP/titanium alloy (Ti) stacks, a machining method of pilot hole with liquid nitrogen cooling (P_hole+LN) was proposed, and the underlying mechanisms of the new method were studied. In this paper, four kinds of drilling conditions were compared, such as P_hole+LN, pilot hole, liquid nitrogen cooling, and traditional dry drilling. The P_hole+LN condition produced the smallest thrust force in CFRP and Ti layer, formed discontinuous titanium alloy chips, and could effectively reduce the interface damage. Therefore, the method of P_hole+LN is suitable for drilling CFRP/Ti stacks.