Research On Residual Stress Of Alumina Bioceramics In Micromilling

It has a wide range of applications as artificial joints and bone substitute materials because alumina bioceramics have excellent properties such as high hardness,good abrasion resistance,heat resistance and good biocompatibility.Higher requirements are put forward for miniaturization,good surface quality and service life of alumina bioceramic parts in the medical field.Alumina bioceramics have the characteristics of high brittleness and low fracture toughness.In the micro milling process,it is easy to form stress concentration and produce cracks on the surface and inside of parts due to the interaction of cutting heat and cutting force.Therefore,it is necessary to study the distribution of residual stress of the machined workpiece under the action of thermal-mechanical coupling.This subject has studied residual stress on the surface of machined workpiece,and has obtained the following research results:1.According to the characteristics of micro milling workpiece with ball end milling cutter,the analytical model of temperature field of micro milling workpiece with alumina bioceramics is established based on the theory of moving heat source and actual micro-milling heat transfer model.2.A three-dimensional micro-milling finite element model of alumina ceramics was established by ANSYS/LS-DYNA software,and the temperature distribution cloud chart and milling force change rule of workpiece in micro milling process are obtained by simulation,and the changes of workpiece temperature and milling force under different milling parameters are studied.A thermal-mechanical coupling model of alumina ceramic micro milling was established,and the residual stress distribution of the workpiece on the surface and in the depth direction was obtained.The effect of different milling parameters on the residual stress of the workpiece was analyzed.3.The experiment platform of micro milling was set up to complete the micro milling experiment of alumina ceramics.The workpiece temperature,milling force,and residual stress on the surface of machined workpiece were measured,the simulation data and experiment data are analyzed and compared by single factor analysis method,the results show that the variation trend of finite element simulation values and experimental values under machining conditions is basically consistent.