| Carbon Fiber Reinforced Plastics(CFRP)are widely used in aerospace manufacturing because of their excellent properties such as high specific strength,high specific stiffness,and corrosion resistance.However,due to its anisotropy,it is easy to have damage defects such as fiber pulling out and delamination tearing in the process of hole making.Therefore,the high efficiency precision hole making technology is facing new challenges.As a new hole making technology,the inclination milling technology can effectively reduce the axial force of hole making and improve the surface quality of hole making.Therefore,based on the basic principles of inclination milling,this paper designed an inclination spiral milling verification device,and carried out experimental research on CFRP inclination milling hole making by focusing on milling axial force,tool wear and hole surface quality.The main contents are as follows:Firstly,through the kinematic analysis of the tool end edge in the process of dip milling,the boundary conditions to avoid zero velocity cutting points in dip milling were deduced.The simulation model of CFRP in dip milling was established by using the finite element method,and the distribution of axial force and boundary stress at the entrance and exit of the hole were predicted and analyzed.Based on the basic principle of dip milling,the structure of the dip milling verification device is designed.Secondly,the research on the cutting performance of CFRP under the oblique-milling process is carried out.The results show that the cutting force increases slowly in the entry stage of oblique-milling,and the average axial force decreases by 60% when it reaches the stable cutting stage compared with that in helical milling.The effects of different cutting parameters on the axial force in dip milling are as follows: feed speed,rotation speed,revolution speed;It is found that the surface quality is better when the dip Angle is 3° by analyzing the test data of dip Angle in the range of 1°～5°.Then,the influence of the number of holes on the tool wear and the surface quality of the hole in the process of Angle milling and spiral milling is studied.It is found that the wear value of the back tool surface in dip milling is less than that in spiral milling,and the layered damage defects in dip milling are less than that in spiral milling.In addition,acoustic emission detection technology is used to monitor the defects in the process of dip milling hole on-line,and finally the damage defects are tested and identified.Finally,in order to reduce the chip accumulation and cutting temperature in the inclination milling process,the chip removal and cooling system of CFRP inclination milling hole is designed,which mainly includes cold air dust collecting cover,vortex tube,dust collecting bag and vacuum generator.In addition,Fluent fluid simulation software was used to optimize the structure of the spiral flow channel,the Angle and height of the dust suction outlet of the cold air dust collector. |
