Study On Characteristics And Preparation Of Porous Stainless Steel Materials Manufactured By SLM

Selective Laser Melting (SLM) is a new kind of3d printing technology. With itsadvantages such as short production cycle, high utilization ratio of the material, SLM is usedto manufacture parts directly. SLM has been developing rapidly in recent years so that it isbecoming mature for preparing dense parts, but the field of preparing for porous parts is stillin the initial stage and there are still lots of questions, especially in the field of making latticedporous material. So, in order to overcome these difficulties, the study on preparationand properties of porous stainless steel material manufactured by SLM was made. The aim ismainly to optimize the process parameters and analyze the properties and microstructure ofcompressive characteristics.The single channel scanning experiment showed that, considering the shape, height andwidth of the single channel single scan line, the range of experimental parametersoptimization was determined. With too thick laser thickness, the stainless steel powder can notbe fully penetrated, leading to balling phenomenon along the scanning direction; with thepulse width becoming larger, the energy of the laser beam becomes larger and eventuallyballing phenomenon appears; pulse frequency becoming bigger, the laser beam energy will bebigger, which leads to the balling phenomenon and then affects the forming quality.The study on forming block parts experiment showed that, with the scanning spacebecoming larger, the block surface quality became smooth and compact, and then wouldbecome loose and not smooth. When the scanning space is0.16mm, the block shape is mostregular and continuous. The density of the blocks is at the highest level of85%when thescanning space is0.16mm and at the lowest level of75%scanning space is0.25mm.Scanning space has great influence on the density as the main reason is that too big scanning space will make the overlap rate become lower, leading to blocks not continuous whenmanufacturing parts.Through the analysis of compressive properties and microstructure, the optimumtechnological parameters of preparation of SLM double channel multi grid shaped porous316L stainless steel material has been obtained. Finally, multi grid shaped porous316Lstainless steel material was manufactured successfully. Along with the increase of scanninglayers, the quality of multi-channel multi grid316L stainless steel skeleton, either the surfaceof the side or the front, becomes worse. When the number of the layers gets70, theexperiment cannot continue. When the grid shaped porous surface was pressed, the placearound the nodes began to crack firstly. Fracture location along the direction of the porosity of thesquare hole, especially near the edge of the frame node, are more likely to occur in the direction of thesquare hole on the fracture.