Simulation Of Hybrid Additive/subtractive Manufacturing Stainless Steel

Hybrid additive and subtractive manufacturing not only solves the difficulty of subtractive manufacturing to produce complex structures,but also overcomes the limitations of poor surface quality and accuracy in additive manufacturing.However,among the factors affecting the hybrid manufacturing quality and performance due to the coupling effect between additive and subtractive manufacturing,residual stress has a significant impact on the deformation.Studies have shown that the residual stress distribution on the surface of hybrid manufactured parts is mainly related to the initial residual stress after additive and milling residual stress.So as to research the coupling effect of hybrid manufacturing that is difficult to directly explore through experiments,this study carried out.the simulation of hybrid manufacturing stainless steel.The main results are as follows :(1)Hybrid additive and subtractive manufacturing model is established.Based on the important assumptions of interaction between laser and metal powder materials,milling tools and metal parts,the thermo-mechanical model of the laser metal deposition and subtractive milling were established.Under the condition of specific cooling time of hybrid manufacturing,the temperature field,deformation and stress field after laser metal deposition are used as the initial conditions for subsequent calculation of temperature,deformation and stress field in subtractive manufacturing.The transfer of temperature and residual stress from laser metal deposition are completed,so as to establish the model of Laser additive and subtractive manufacturing.(2)The multi-dimensional evaluation index verifies the numerical model of hybrid manufacturing model.Based on the process of laser metal deposition and subtractive manufacturing,the numerical model of hybrid manufacturing are established,and laser metal deposition temperature,laser metal deposition deformation and hybrid manufacturing milling force were selected as the evaluation indexes.The proposed normalization method that eliminates the height deviation caused by the fluctuation of additive manufacturing process parameters realizes the direct comparison of deformation prediction results.Combined with the results of hybrid manufacturing experiments and numerical model,the accuracy of hybrid manufacturing numerical model is verified and quantitatively described from multiple dimensions.(3)The influence of process parameters on heat / force / deformation was analyzed.Combined with the simulation results of hybrid manufacturing model and measured results,the effects of different laser power,scanning speed and scanning strategy process parameters on laser metal deposition temperature and upper surface deformation of parts are analyzed,and the effects of back cutting,side cutting,feed speed and spindle speed milling process parameters on milling force of hybrid manufacturing are analyzed.