High reliability model of mechanical response in drilling of CFRP/Al stacks

CFRP/Al laminate material is widely used in aerospace due to its advantages of light weight and high machinability. For assembling, crowded assembly holes need to be drilled for CFRP/Al laminate products. However, the damages of burr, delamination, and tearing appear frequently in drilling without precise guidance by mechanical response model. In order to reduce the machining damages, in this paper, a high-reliability mechanical response model is established for each stage in laminate materials drilling to ascertain the matching method between materials, tools, and cutting parameters. The theoretical expression of drilling thrust based on the thin plate theory is established considering the influence of cutting parameters, and further corrected with the cutting parameter correction terms to predict drilling thrust force, and further guiding the optimization of drilling parameters. According to the experimental results, the proposed model has a reliability greater than 97.3% and a prediction deviation lower than 13.2% in CFRP/Al laminate material drilling thrust force prediction. In the cutting with optimized parameters from the proposed model, the inlet orifice of the laminated material has no flanging burr, and the CFRP layer exit orifice has no defects as burr, delamination, or tearing.