Finite Element Analysis And Experimental Study Of Thin-Wall Parts Processing On Selective Laser Melting

Thin-wall metal parts have been applied greatly with advantages of light weight,compact structure and saving material.However,thin-wall parts are usually complex in structure,low in rigidity,and small in wall thickness.They are easily deformed when they are manufactured using traditional techniques such as milling,turning,casting,forging,and welding,affecting the machining accuracy and quality.Selective Laser Melting(SLM)is a laser manufacturing technology that can build metal parts with near full density and excellent mechanical properties.SLM can process complex parts that are difficult to process in traditional methods,so it is very advantageous to machine thin-wall parts.However,the current research on thin-wall parts using SLM is based on experimental.The temperature distribution,stress distribution of thin-wall parts,and the difference between thin-wall parts processing and bulk processing by SLM have not been thoroughly studied.Firstly,this paper analyzes the temperature field of thin-wall parts by Finite Element Method(FEM).In the study of the temperature field,the effects of different laser powers and scanning speeds on the size of the molten pool have been analyzed.And the molten pool size of the thin-wall parts and the bulk parts under the same process parameters are compared.The study found that the thin-wall parts' molten pool have larger length/width values.Therefore,the thin-wall parts processing more likely to cause balling.The fluctuation of temperature of thin-wall parts and bulks have also been compared.It has been found that the cooling rate of thin-wall processing is slower.Therefore,the best scanning length of thin-wall part processing is greater than that of bulk processing.Secondly,based on the temperature field,the stress evolution and the stress distribution of thin-wall parts are studied.The results show that the stress of the thin-wall parts is mainly concentrated on the left and right and top of the parts.The left and right are dominated by the Z-direction stress,and the top is dominated by the X-direction stress.And in the multi-line thin-wall processing,partition scanning can effectively reduce the stress of thin-walled parts.Finally,based on the FEM,the experiment of thin-wall processing was conducted.The correctness of the FEM model is verified by measuring the thickness of the thin-wall parts and comparing it with the results of the FEM.Obtained the process parameters that can process continuous and stable thin-wall single track by observed the top view of the single track.The deformation of thin-wall parts with different partition lengths was measured,which verify that partition scanning can reduce stress and obtain better partition lengths.