The Study Of Burr Suppression Strategy For Variable Parameter Drilling Of Aviation Stacked Materials

CFRP(Carbon Fiber Reinforced Plastics)is widely used in aviation manufacturing because of its light weight,high strength and strong impact resistance.In the process of aircraft assembly,the drilling of CFRP/metal stacked materials is often faced.Improving the drilling quality and efficiency of this stacked materials has positive significance for aircraft assembly.This paper proposes a various feed drilling method based on sinusoidal curves in order to achieve the purpose of inhibiting the surface burrs of stacked materials and improving surface quality.The drilling experiment research,analysis and optimization of CFRP material and CFRP/Al stacked materials based on sinusoidal variable feed drilling method were carried out.(1)On the basis of analyzing the damage mechanism of CFRP machining,and based on the sine curve of the mathematical curve,a variable feed drilling method is proposed.A full factorial experimental design is used to verify the method,and the effect of variable feed drilling on thrust force,exit delamination factor,hole wall roughness and surface topography is shown compared with conventional drilling.From the perspective of cutting motion,it provides a technical basis for improving the quality of one-time drilling of laminated materials.(2)The formation mechanism of drilling damage in CFRP/Al stacked materials was explained,and the effect of variable feed drilling on the surface quality of CFRP/Al stacked materials compared with conventional drilling was studied.By analyzing the surface quality evaluation indexes of the drilled-in area,the stacked area and the drilled-out area,it is found that the variable feed drilling method can effectively improve the surface damage of the CFRP/Al stacked components.(3)Because it is impossible to know the optimal process parameters for the tool to drill in and out when the variable parameters are selected.In order to obtain the optimal cutting parameters required for each stage of the laminated material to suppress the formation of burrs,the influence of different cutting parameters on the surface quality of the stacked materials was analyzed.Selecting the entrance delamination factor,exit burr height and material removal rate(MMR)as the optimization objectives,the objective function is solved by using the multi-objective genetic algorithm and Kmeans clustering algorithm.The results are verified by experiments,and the optimization of cutting process parameters for the variable feed drilling method is realized.Finally,the error source between the experimental value and the optimization result is analyzed and summarized.When the CFRP / Al stacked materials are drilled,the proposed variable feed drilling method reduces the fiber tear factor of exit by 3.28%,and the burr height of exit is reduced by 31.65%.Experimental verification,the entrance delamination factor error of the optimized process parameters is 3.6%,and the exit burr height error is up to 11.6%,and the engineering application can be accepted.Some of the research results obtained in this paper have a certain reference value for a drilling process of aircraft stacking material structure.