Study Of Machanism And Craft Of Ultrasonic Vibration Aided Drilling Ti6Al4V

Ti6Al4V has been widely used in manufacturing due to their excellent strength to weight ratio and high temperature corrosion resistance.However,due to its low thermal conductivity,small elastic modulus,and severe work hardening,titanium alloy is a difficult material,which will lead to excessive tool wear and high temperature in the traditional process.Ultrasonic assisted drilling is a kind of non-traditional mixed processing technology.In the process of drilling hard materials,cutting force and temperature can be reduced,which is beneficial to chip breaking and chip removal,surface processing quality improvement,and tool life improvement.In this paper,ultrasonic vibration-assisted drilling of titanium alloy Ti6Al4 V is analyzed,which mainly includes the following aspects:(1)The theoretical and method research of relevant physical quantities in drilling and machining is introduced,and corresponding theoretical guidance is provided for the simulation process of drilling and machining.The properties of titanium alloy,the principle of ultrasonic vibration drilling,the thickening cutting characteristics of ultrasonic vibration drilling and the variable speed cutting characteristics of ultrasonic vibration drilling are introduced.A simplified mechanical model of the force exerted on chips by cutting edge,chip slot and hole wall during drilling is established.The finite element software deform-3d is used to carry out the simulation test of the traditional drilling and ultrasonic vibration assisted drilling process.The basic theory of finite element simulation and the key techniques of finite element simulation for metal cutting process are described in detail.(2)The three different point angle(140°,120°,90°)drill bits were used to analyze the effect of various drilling parameters such as feed rate,spindle speed and vibration frequency on performance characteristics such as thrust force,effective stresses,temperature,and chip morphology in conventional drilling(CD)and ultrasonic-assisted drilling(UAD)of Ti6A14 V using in order to optimize the chip breakability of Ti6A14 V.The three different point angle drill bits are utilized to establish the finite element models(FEM)to simulate the drilling process with Lagrangian approach in DEFORM-3D software.The simulations are validated by the experimental findings and analytical data of thrust forces,and the percent errors in results range approximately between 3 and 7%.The results obtained prove that UAD can produce segmental discontinuous chip,lower thrust force,lower process temperature,and lower effective stress.The point angle of 120° drill achieved the thinnest chip thickness and the excellent effects of chip breaking.The achieved results are assumed to help for the optimization of the drill tool geometries,drilling parameters and chip breakability.(3)The twist drill bit and 3-flute drill bit were used to analyze the effect of various drilling parameters such as feed rate,spindle speed on performance characteristics such as chip morphology,thrust force,temperature,and tool wear in CD and UAD of Ti6A14 V The twist and 3-flute drill bit are utilized to establish the FEM to simulate the drilling process with Lagrangian approach in DEFORM-3D software.The results of the simulations not only reveal obvious varying regular pattern of thrust force,temperature,tool wear depth,chip thickness and damage with the increasing of feed rates,spindle speeds,which confirm the capability and advantage of FEM of the drilling process,but also provide a more profound knowledge about the drilling mechanism including the effect of 3-flute drill bit in UAD on chip breakability and tool wear.