| With the rapid development of the aviation manufacturing industry,the requirements for the quality of assembly holes have become more stringent.Therefore,the low damage drilling of carbon fiber reinforced matrix composites(CFRP)needs to be further studied.In this thesis,a new type of plane rake faced twist drill is used as the research object to explore the feasibility of CFRP drilling.And to study the low damage behavior of aviation carbon fiber composite materials,the main research contents are as follows:1.A model was proposed to predict the thrust force generated during CFRP drilling with plane rake faced twist drill.In this model,the theory of contact mechanics is applied to the chisel edge cutting area of the plane rake faced twist drill,and the thrust force model of the main cutting edge with three different deformation regions is established.The model contains the geometric parameters of the tool,the parameters of the material and the processing parameters.The thrust force predicted by the model and the experimental results are satisfactory under different feeds per revolution.Therefore,it is concluded that the model can be used to optimize the processing parameters of plane rake face twist drilling for CFRP.2.A comparison experiment was conducted between plane rake faced twist drill and common twist drills with the same reference rake angle at the outer corner of lip.Through the comparison and analysis of the thrust force change process and drilling damage of the two kinds of tools,it is studied whether the plane rake faced twist drill has the characteristics of low drilling damage compared with the common twist drill.Then,the effect of plane rake faced twist drill with different reference rake angles on burrs and delamination at the entrance and exit was studied,and the formation mechanism of burrs was explained in detail.Finally,the inhibitory effect of the thin woven glass fiber surface layer on the CFRP laminate was verified.3.The plane rake faced twist drill with different helix angles,apex angles and clearance angles are used for drilling experiments.What kind of geometric structure of the plane rake faced twist drill tip structure has drilling quality.The influence of plane rake faced twist drill with different geometric angles on the thrust force and the drilling quality at entrance and exit is analyzed,and the geometric structure of plane rake faced twist drills is optimized. |
