Research On Optimization Of Milling Tools And Cutting Process For Low-damage Milling CFRP

Carbon fiber reinforced ploymers are widely used in aerospace field due to their high specific strength,specific modulus and strong designability.However,anisotropy and low interlaminar bonding strength lead to burr,tear,lamination and other damages in CFRP machining.Restraining CFRP machining damage and improving machining efficiency have become difficult problems in the field of aviation material processing.In order to reduce the machining damage of CFRP,the structure,coating and cutting technology of CFRP milling tool were studied.The main research contents are as follows:Based on the theory of interlaminar and intralaminar damage,a dynamic simulation model of CFRP 3d milling was established.Based on CFRP threedimensional Hashin failure criterion,the damage evolution model of interlaminar elements was established.The layers are connected by cohesive element to simulate the generation and expansion of interlaminar damage.The accuracy of the model is verified by cutting experiments,which can effectively predict the size of cutting force and the variation rule of interlaminar damage.Based on the established CFRP 3D milling simulation model,the structure optimization design of CFRP special tool was carried out for the purpose of reducing interlaminar stress and interlaminar damage.It is found that compared with ordinary milling cutter,the cutter with herringbone tooth structure and multi-edge micro-tooth structure can effectively reduce the interlayer stress and damage.The influence of key structural parameters such as left and right helical angle combination,rake and clearance angle,shape of micro-tooth,shape of left-lateral chip slot section on cutting force,interlayer stress and interlayer damage of double-helix and multi-tooth cutters was analyzed,and the structure optimization of cutters was completed.The optimization of CFRP milling process was studied based on the optimized CFRP milling tool.The variation of cutting force and machining quality of two kinds of cutting tools at different cutting speed,feed speed and cutting depth were analyzed respectively.It is found that the cutting force and machining quality are affected the most by the feed speed,and the cutting speed is too large or too small to reduce the machining quality,The greater the cutting depth,the better the machining quality of double-helix cutter.In order to reduce cutting stress,restrain burr,delamination,tear and other machining damage,two kinds of cutting technology optimization were completed.Diamond-like Carbon coatings and diamond-coated tools were prepared.Through cutting experiments,the wear evolution of different tools and the evolution law of CFRP machining damage were revealed,and the cutting performance of different CFRP was verified and evaluated.In this paper,the CFRP 3D milling simulation model is established,and the optimization and verification of special milling tool structure and machining process are completed.The research results will provide a good technical and theoretical reference for low damage and high efficiency processing of CFRP.