Research On Support Design Of Selective Laser Melting Forming Part

Selective laser melting(SLM)is a type of laser rapid manufacturing technology which can directly form metal parts.This technology uses high energy beam laser to metal powder,and stack by layer to form arbitrarily complex shape metal parts.Due to the restriction of the SLM forming principle,for some parts with high precision,especially the complex structure,the forming defects are easily caused by support during forming parts.In order to meet the quality of SLM forming metal parts,the requirements for support design and setting are higher.Therefore,the supporting role of selective laser melting process is studied in this paper,and the support design of the forming part is put forward from the perspective of supporting role.In this paper,316 L stainless steel powder is selected as SLM molding material.In view of the forming defects of parts,the paper studies the role of support in the forming process.The paper studies on the forming mechanism of melting point lap on the support.The main contents are as follows:1.This paper designs a flake support structure as an experimental device to stabilize the single track on the support.It can control the forming span of the melted channel by changing the angle.The paper studies the effect of the laser process parameters and the support spacing on the forming continuity of single,double and multichannel monolayers.The method of controlling laser energy density and reducing the distance between support points can continuously molding single channel.The maximum span of single channel is 0.4mm,and the limit cantilever length is 0.3mm.2.For face molding problem,the paper studies the influence of different support spacing on multi-layer molding.With the increase of forming height,the forming surface has undergone a process of changing the shape of strip gap,circular holes and pit.The gap of the first layer is perpendicular to the laser scanning direction,and the Z axis compensation height of support structure is determined to be three layers.The shrinkage rate between the layer is 0.3.The paper studies on the layer thickness influence on the forming angle limit,the results show that reducing thickness can improve the ultimate shop powder forming angle.3.Based on the multi-layer forming experiment,the paper establishes the finite element model of the stress field of multilayer forming.This paper studies the influence of support distance and support XY compensation distance on the thermal deformation of the forming layer.During the SLM forming process,the function of supporting is transformed from the control of the shape of the channel and layer to control the whole thermal deformation.Combined with the supporting role in the forming process,the paper puts forward the design and optimization method of support for the typical feature structures,which improves the forming reliability of the parts.