Optimization Of Drilling Processing Parameters For Ti-CFRP-Ti Laminated Material

With the development of aerospace industry,the laminated structures of carbon fiber reinforced plastic(CFRP)and titanium alloy are more and more widely used in aerospace structures.However,due to the great differences in mechanical processing and physical and chemical properties between carbon fiber reinforced composites and titanium alloys,the quality of holes in Ti-CFRP-Ti laminates is difficult to be guaranteed,and the tool wear is very serious in the process of drilling Ti-CFRP-Ti laminates.How to achieve "high-efficiency integrated drilling" on the premise of ensuring the quality of drilling is a major problem in the field of Aeronautics and astronautics.In this paper,the variable parameter pecking drilling method is used to study the hole drilling technology of Ti-CFRP-Ti laminated materials,and the drilling parameters are optimized.The main contents of this paper are as follows:(1)Determing the geometric parameters of drilling tools for Ti-CFRP-Ti laminated materials.Taking carbon fiber composites and titanium alloys as processing objects,the influence of the top angle and helix angle of twist drill on the drilling axial force,drilling temperature and hole exit morphology during the drilling of carbon fiber composite and titanium alloy were studied respectively by using full factor test method.And the geometric parameters of hole-making tools suitable for drilling carbon fiber composites,titanium alloys and Ti-CFRP-Ti laminated materials were determined.(2)Experimental study on variable parameter pecking drilling of Ti-CFRP-Ti laminated materials.Based on variable parameter pecking drilling technology,the effects of changing drilling parameters at different axial positions on the drilling axial force and drilling temperature during the drilling process of Ti-CFRP laminated material and CFRP-Ti laminated material were studied,and the optimum variable parameter position in the process of variable parameter pecking drilling of Ti-CFRP-Ti laminated material was determined.The influence of spindle drilling speed and feed rate on drilling axial force,drilling temperature and surface roughness of Ti-CFRP-Ti laminated material was studied by orthogonal test method.Mathematical models of drilling axial force and surface roughness of hole inner wall were established by regression analysis method,and their accuracy was tested.(3)Parameter optimization of variable parameter pecking drilling for Ti-CFRP-Ti laminated materials.Aiming at the surface roughness,drilling axial force and material removal rate of hole inner wall,the optimization model of drilling parameters of TiCFRP-Ti laminated material in pecking drilling process with variable parameters was established.The optimal parameters of spindle speed and feed rate in the drilling process of Ti-CFRP-Ti laminated materials are obtained by using the Non-dominated Sorting Genetic Algorithm with elite strategy(NSGA-II),and the optimization effect was verified by experiments.