A review on the drilling of CFRP/Ti stacks: Machining characteristics, damage mechanisms and suppression strategies at stack interface

Carbon fiber reinforced polymer (CFRP)/titanium alloy (Ti) stacks have promising application in aerospace field due to their excellent mechanical properties. During integrated drilling of CFRP/Ti stacks, the machining process at interface between CFRP and titanium alloy is very complicated. The interaction among CFRP, titanium alloy and cutting tool leads to poor processing quality, serious tool wear and other problems. In this paper, in order to deeply analyze the influence mechanism of interface area on the machining process, the research achievements and progress of drilling CFRP/Ti stacks are reviewed. Special attention is paid to the machining characteristics and CFRP damage mechanism at stack interface during drilling and helical milling of CFRP/Ti stacks. The cutting force characteristics, temperature characteristics and tool wear characteristics of interface machining are analyzed, and the damage mechanism and evaluation method are summarized. In order to solve the existing problems in drilling CFRP/Ti stacks, the suppression strategies of interface damage in recent years are discussed from four aspects: machining parameters, machining environment, tool structure and advanced machining technology. The research trend of laminated interface machining is prospected, which provides an important reference value for the realization of precision, high efficiency and low damage integrated drilling of CFRP/Ti stacks.