Study On Temperature Field And The Design Of Cooling System In Helical Milling Of Titanium Alloy/CFRP Stack

Carbon fiber reinforced composite material(CFRP)has been widely used in many aviation manufacturing industries.Drilling integrated hole with laminated member(Ti/CFRP)has become one of the difficult problems in aircraft manufacturing.High Cutting temperature in the process of integrated hole making of laminated components is an important factor causing serious tool wear,interfacial damage.Based on the helical milling hole principal,this paper analyzes the generation,conduction and interface transfer behavior of the cutting heat of the Ti/CFRP laminated members.The analytic model of the cutting temperature field is established.The auxiliary heat dissipation system is designed.The main contents of this paper include the following aspects:Based on the kinematics of helical milling hole,the interfacial heat transfer mechanism of Ti/CFRP laminated members is analyzed.The heat transfer coefficient of cutting and the interface temperature conduction coefficient of workpiece are solved,and the analytical model of cutting heat transfer is established.Through the comparison of the experiments results,it is found that the analytic model has high accuracy and can provide a theoretical basis for the optimization of the machining process of Ti/CFRP helical milling hole.The auxiliary heat dissipation system of helical milling hole is designed,including chip extractor,vacuum cleaner and tool internal cooling device.Taking into account the heat dissipation and chip-collecting of dust collector,the optimization model of cover structure is established based on fluid dynamics,and it is found that the effect of inlet angle 40°,outlet angle 20°,inlet height 24 mm,outlet height 38 mm and Gap distance 15 mm is the best.The distribution of cutting temperature field under auxiliary heat dissipation system is analyzed.It is found that the heat dissipation system can effectively promote heat dissipation and reduce cutting temperature.In this paper,the cutting force,cutting temperature,tool wear and hole quality in the experiments of helical milling hole under different heat dissipation conditions are compared and analyzed,and it is found that the heat dissipation system has effective chip collecting and chip removal ability.Compared with dry cutting condition,cutting temperature decreases 33%~50%,cutting force decreases 25%~34.3%,which can effectively reduces tool wear and improve the quality of processing.The above research can provide theoretical support for the process optimization and cutting temperature control of titanium alloy/CFRP helical milling hole,and it also has important reference value for the damage suppression of helical milling hole making process.