| CFRP has excellent mechanical properties and is widely used in various fields.However,due to material anisotropy,high hardness,poor thermal conductivity and other characteristics,in the drilling process of CFRP,it is easily caused CFRP to delamination,tear and burr in the hole entrance,tool life reduction and other defects.To solve the above problems,this paper will study the following aspects:First of all,the cutting mechanism and defects of CFRP were studied,and the microscopic morphology of single-layer CFRP plate and hole wall after drilling was observed and analyzed,can get the conclusion:Different forms of CFRP formed in different 0 angles are different;Carbon fiber fracture surface and the resin substrate coated surface composed of two parts of the CFRP pore wall micro-surface;In the range of 0°to 360 °,the roughness of the surface is symmetrical.According to the force model of CFRP,the axial force F_of the tool is affected by the angle of ?,the machining parameters of the tool and the geometric parameters,It is theoretical support for the optimization design of the rotary cutter tool.Then,the feasibility of CFRP rotary cutter experiment at different feed speed vf and speed n of rotary cutter tool,twist drill,trepanning drill,comparative analysis on three kinds of cutting tool of the axial force of the size of the Fz.And using MATLAB to fit the data,the binary quadratic empirical formulas of three kinds of tools Fz are obtained.The analysis can be obtained:When n is certain,Fz increases with the increase of vf,and the variation trend is almost linear;When vf is certain,Fz decreases with the increase of n,and the smaller the vf,the change is more obvious;When the three kinds of tools in n = 5000r/min and vf = 150mm/min,the axial force of the rotary cutter is minimum,the processing quality is better.It can verify the feasibility of the rotary cutter tool.Secondly,design the structure of the rotary cutter tool,based on HASHIN criterion,using ABAQUS to simulate CFRP 3D drilling,by changing the geometric parameters of the tool,after getting an optimized angle value,then do orthogonal drilling experiment,By measuring the axial force of Fz and CFRP to determine the processing quality of entrance,thus obtains the optimal combination of geometric angle of the cutter the rake angle ?0 =15° degrees angle ?0 = 10° the main deflection angle kr?75° side angle kr'?5°.According to the influence degree of Fz is as follows:the main deflection angle>rake angle>side angle>degrees angle.Consistent with the simulation results,the deviation is within acceptable limits.The curve and the expression of the average tear length L,about Fz are obtained by MATLAB,and the results show that there is a positive correlation between them.Finally,the ultrasonic flaw analysis of CFRP was carried out by using ultrasonic C-scan,and the result showed that the delamination factor was positively correlated with Fz.At the same time,the tool wear experiment was carried out on the rotary cutter with optimized geometrical angle,and the distribution of VB value was almost linear with Fz.Therefore,Fz can be used to predict the degree of stratification defects and the general wear of the tool.The main failure form of rotary cutter tool is flank wear and tool chipping failure. |
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