The Reserach On Heat Conduction Mechanism And Bit Wear Characteristics Of Nickel-Based Alloy Deep-Hole Vibration Drilling

Nickel-based alloy materials are widely used in nuclear power,aerospace,and atomic energy industries due to its excellent comprehensive thermodynamic properties.However,the extremely poor machinability of nickel-based alloys,coupled with the inherent difficulties of deep-hole machining in cutting heat dissipation and difficulty in chip removal,making the deep-hole machining of nickel-based alloy materials a bottleneck technology that needs to be resolved.The vibration drilling is an effective improvement method in mechanical processing,and its technological effect has been widely recognized.Therefore,this paper aims at the practical problems such as high cutting temperature,low tool life,and poor surface quality of the nickelbased alloy deep-hole drilling process.Based on the analysis of the vibration drilling kinematics and drilling force model,the method of combining analytical method and finite element simulation to study the heat conduction mechanism of the deep-hole vibration drilling process,and through the nickel-based alloy deep hole vibration drilling experiment to study the wear mechanism of the drill.It provides theoretical basis and practical guidance for deep-hole processing of difficult-to-machine materials such as nickel-based alloys.The working principle of the staggered teeth BTA axial vibration drilling system was analyzed,and on the basis of that,the axial vibration drilling kinematics model was established;Analysis of the chip breaking mechanism of vibration drilling,and numerical simulation analysis of the chip shape under continuous drilling and intermittent drilling;The theoretical calculation formula of dynamic cutting thickness and dynamic cutting angle during vibration drilling was deduced.Force analysis of the staggered tooth BTA bit,and deduced the calculation formula of the bit axial force and torque;Using the orthogonal cutting force model,based on the unit shear cutting force model,the BTA drilling tooth cutting force model and the minor cutting edge force model were established.According to the principle of staggered BTA drilling,the heat conduction model of BTA deep hole drilling was established;The heat generation and transmission during the drilling process were analyzed,and the heat conduction model of the cutting tooth heat source and the heat conduction model of the guide bar extrusion friction heat source were established.Theoretical analysis of the intermittent heat transfer process of vibration drilling,based on the cutting force model of the cutter tooth,the heat flux density introduced into the rake face of the cutter tooth under the conditions of ordinary drilling and vibration drilling was calculated.Based on the basic principles of heat transfer,a heat conduction model of the tooth rake face is established,and the heat conduction control equation is numerically solved by the green function.Based on the Deform-3D finite element simulation software,the ordinary drilling and the vibratory drilling process finite element simulation models of the Inconel-718 were established respectively.Comparative analysis of the chip forming process and chip shape under the two processing methods,as well as the changing rule of the instantaneous chip contact length;The drilling force and temperature field of the drill bit were simulated and analyzed.The BTA deep-hole vibration drilling experimental platform was built to carry out ordinary drilling and vibration drilling experiments of nickel-based alloy materials.The effects of different processing parameters on chip morphology,drilling force,cutting temperature and tool wear were compared and analyzed through experiments.The machinability of nickel-based alloy materials under deep hole drilling conditions was studied.At the same time,the theoretical analysis and simulation results are verified through experiments.The results show that vibration drilling can effectively improve the cutting heat exchange environment of the drilling system,reduce the severity of tool bonding wear and reduce the formation of chip nodules.