Experimental Study On Milling Of Additive Forming Part Of TC4 Titanium Alloy

TC4 titanium alloy aerospace parts have gradually begun to develop towards the direction of "structural lightweight" and "structural and functional integration".Selective Laser Melting can manufacture complex titanium alloy structure parts which can't be made by traditional process.But the precision and surface quality of parts manufactured by Selective Laser Melting technology can't meet the requirements of use.So the parts need to be milling.Therefore,in order to improve the surface quality and milling process of additive forming parts,finite element simulation and milling test were conducted based on the metal cutting theory to study the influence of various milling process parameters on the milling performance of TC4 additive forming parts.The main research contents are as follows:Firstly,based on the deformation principle of metal cutting,the orthogonal cutting theory and bevel cutting theory are analyzed and studied,and the relation formula of bevel cutting and orthogonal cutting is obtained,and the mathematical model of cutting force prediction is established based on the bevel cutting model.Then,the finite element simulation technology and Advantedge FEM simulation software are described,and the implementation criteria and key technologies of finite element technology are introduced.The material constitutive model of TC4 additive was defined by finite element simulation software,and the milling simulation test was carried out.The changes of residual stress,milling force,milling temperature field and chip shape were analyzed.What's more,according to the principle and characteristics of Selective Laser Melting additive forming technology,SLM additive forming parameters were selected in combination with test equipment and reference to a large number of literature to prepare TC4 additive forming parts.The surface morphology,density and microhardness of TC4 additive forming samples were measured by ultra depth of field microscope and scanning electron microscope to ensure the rationality of the forming parts.The orthogonal milling test scheme was designed.The milling force and surface roughness were taken as the indexes to compare and analyze the machability of TC4 additive forming parts and TC4 forgings with the same element,and the relationship between the milling parameters and the milling performance indexes was analyzed.Furthermore,the mathematical models of milling force and surface roughness of TC4 additive forming parts were established by multiple regression analysis,and the significance and fitting of the models were verified.Finally,in order to achieve high efficiency and quality of TC4 additive forming parts milling,the minimum milling force,the minimum surface roughness and the maximum processing efficiency(represented by the maximum material removal rate)were taken as objective functions,and the multi-objective optimization solution method of genetic algorithm was adopted to obtain the optimal milling parameter combination.the best milling parameters optimized combination of spindle speed is 2411.562 r/min,the feed speed is136.885 mm/min,turning back to 0.456 mm,lateral turning is 2.369 mm.