Modeling And Experimental Investigation On Temperature Field For Micro-Milling Of Ti6Al4V Thin-Walled

With the rapid development of micro-milling technology,monolithic and complex thin-walled components have been widely used in the aerospace field.In order to achieve weight reduction and increase specific strength,titanium alloy Ti6Al4V has become the main material for thin-wall processing.However,its poor thermal conductivity,small elastic modulus and lively chemical properties lead to high cutting temperature of thin-wall Ti6Al4V during machining,which affects the quality of the thin-walled surface machining and shorten tool life and reduces the processing efficiency.Based on the above problems,this paper studies the temperature field of micro-milling Ti6Al4V thin-wall milling.This paper analyzes the generation and division mechanism of heat sources in micromilling,and divides the micromilling temperature field into four heat source temperature zones.Combined with the mechanism of microcutting and heat source theory,an instantaneous finite-length moving belt-shaped heat source model is eatablished.The micro-milling heat transfer model under the influence of four heat sources is given,and a comprehensive heat source of four heat sources is established.The temperature analytical model of the thin wall,micro-milling cutter and chip of Ti6Al4V is determined,and the parameters of the micro-milling temperature model are determined.The numerical iterative algorithm for the thin-walled Ti6Al4V thin wall is established,and the thin-walled temperature change surface map is obtained.The theory of crack propagation energy is used,and a radial return stress updating algorithm is used to compile the sub-program for the TANH constitutive model of Ti6Al4V material.The two-dimensional cutting simulation was used to verify the VHMAT subroutine of the TANH constitutive equation.The stress-strain curve of Ti6Al4V is shown,which proves the correctness of VUMAT subroutine programming.The TANH constitutive model is used to simulate the thin-wall three-dimensional micro-milling process of Ti6Al4V.The stress-strain curves of Ti6Al4V under three-dimensional micro-milling conditions are studied.The temperature field curve of thin-wall,micro-milling cutter and chip of Ti6Al4V is obtained.The temperature variation curves of four heat source regions are given and the variation of milling force is studied.A thin-wall temperature measurement program for Ti6Al4V is developed,and a Ti6Al4V-constantan thermocouple is calibrated.The thermoelectric characteristics of Ti6Al4V-constantan are obtained.A thin-walled temperature measurement platform for Ti6Al4V is built,and a semi-artificial thermocouple temperature measurement experiment is designed.The temperature variation curve of the thin wall of Ti6Al4V is obtained,and the theoretical,simulated and experimental values are compared and analyzed and analyzed to prove the correctness of the theoretical model of micro-milling temperature.