Study On The Forming Process And Optical Properties Of Selective Laser Melting Co-cr Alloys

3D printing is a new manufacturing technology, which based on the digital model, stacking materials step by step into physical components. It is an important part of advanced manufacturing technology, and Selective Laser Melting(SLM) belongs to the typical metal 3D printing technology. Currently, SLM technology in foreign countries has been widely used in the aerospace, automotive, biomedical and other fields, and the domestic application of this skill in the aerospace field has reached the international advanced level. But in other areas our country, especially the biological medicine field which needs a lot of personalized implants, the technology is not mature and we are short of relevant research. Moreover, the domestic base is relatively weak in the aspect of equipment design,core components, materials and the molding software.Based on equipment design and process optimization research, we used the selfdeveloped laser melting equipment conducting systematic cobalt-chromium alloy molding process optimization study, and the study was carried out with the background of oral applications. We got the reasonable process window and the preliminary optimization parameters through the experiment of single-layer single-channel molding; Single-layer multi-channel experiment determines the effect of overlap rate on the molding quality; Finally, orthogonal experiment was adopted to interpret the influence laws of laser energy density, constituents content, layer thickness, and interlayer strategy on the properties of body molding parts, and the product performances’ inner links were expounded.Results showed that a stable fitting relationship could be obtained between laser energy density and weld width with the optimized process parameters, which provides a reasonable reference for single multi-channel and body shaping. The adjacent cladding channels can be lapped closely when the overlap rate was 35% with the surface roughness as low as 5μm because the expansion height of the remelting portion was reasonable. The influnce priority order of process parameters on surface roughness is layer thickness > laser energy density > constituents content > interlayer strategy the same as the effects on relative density, and various factors influence trend on both properties were opposite.Melting shrinkage and thickness accumulation of the powder layer were the important factors of molding quality deterioration; the smaller of the surface roughness cumulative effect, the fewer pore in the body is, which leads to a high relative density; Furthermore, macro-hardness of the part has a significant dependence on relative density. The relative density of the workpiece with the optimal process parameters is 98.04% and the macro-hardness of the workpiece with the optimal process parameters was 40 HRC, conforming to ASTM standards.