Research On The Equipmentand Fabrication Process Of Selective Laser Melting

Selective laser melting(SLM) techinqe was developed on the base of Selectivelaser sintering(SLS). The techinque fabricated metal parts direct using metal powder.SLM possessed the convenience of the SLS. Compare to the SLS technique, in theprocess of fabrication, SLM could get the metal parts with a metallurgical bond,compact structure and very high precison. This techinque could avoid thepost-treatment process of low melting point metal infiltration and this is the hugeadvantage in the process of melt parts fabrication. Although SLM fabrication has thecompetitive advantage in the materials selection, design free degree and research costand so on, the strict requirements to the equipment and the unstability of keytechniques confine the application and extension of SLM. The research on the SLMnow is focused on the fabrication process experiments, application fields explorationand hardware development. Many problems have to be solved on hardware structure,fabrication process optimization and forming mechanism. According to the presentresearch, we focused on the fabrication equipment and forming process research.According to the present SLM equipments material, one SLM fabricationequipment was designed by ourselves. The powder feeding and preparation deviceswere optimized and modified. Powder box structure was adopted. This structureunited the powder preparation and feeding structures to one mechanical structure. Thepowder preparation action was completed at the same time of feeding the powder tothe fabrication space. The scanning precision of the scanning galvanometer, movingprecision of Z axis and the protect effect of fabrication room was tested. The resultsshows that the scanning galvanometer could get the precision within50μm and Z axiswithin10μm. The equipment could satisfy the fabrication precision requirment.On the base of SLM equipment,316L stainless powder was used to research thefabrication process. Fisrt, research on single track fabrication was done in order to fixa reasonable fabrication parameters window. On that foundation, a group oforthogonal experiment was designed and the surface roughness of samples was tested.After analysing the effect of every factors to the surface roughness, the suitableprocessing parameters could be acquired. The compact metal parts could be fabricatedwith the optimizational parameters. Macroscopic hardness of the samples was testedand the average hardness of samples are370HV, higher than the ordinary316L parts.