Research On Macro-quality Of Stainless Steel Parts By Selective Laser Melting

Selective Laser Melting (SLM) is a new kind of rapid processing technology which is simple molding and can directly produce the terminal metal productions. Because of the recent development of SLM technology, the reports about the macro-quality of molding parts are few, which retard the further study of the technology. As a result, the developing research based on SLM of molding parts'macro-quality is very important.Firstly, this thesis studies the regulation of the height and width of single cladding, which are affected by the laser power, the laser scan velocity and the energy density. Based on the former theory, a further experiment analyses the changing regulation of the measurement precision by fabricating a wall of 10mm height. The research finds out that the parameter range is laser power 170W, scan velocity is from 36m/min to 48 m/min and the thickness of slice is from 0.2mm to 0.35mm when the molding precisions are±0.1mm. In the scope of technique parameters, the researchers successfully select the proper parameters to produce a complex structure with the size of 27×12×10mm3 in high precision, whose average error reaches±0.172mm and the deviation concentrates at 0.002mm.Then, based on the method of the design of the orthogonal experiment, the thesis investigates the roughness of the surface of molding parts and finds that the laser power is the main factor. By optimizing parameters the researchers finds out that when laser power reaches 143 W, the scan velocity is 12m/min and the overlap is 0.5 would be the best. Furthermore, through the method of changing the thickness of the slice and tilt angleα, the thesis researches the roughness of the side face of the molding parts. From the research, the roughness of the side face is direct proportional to the height of the slice and is inversely proportional to tilt angle. When the thickness of the slice reaches to 0.2mm and the tilt angle is 90°, the roughness of the side face achieves the minimum.Moreover, a 10×10×10mm3 metal cubic is made by technique parameter optimization. Through measurement and calculation, the density of the metal cube reaches more than 96.8%.Finally, the thesis research the ultimate tilt angle of the thin-sheets in different thickness of slice, and finds out that when the thickness of the slice is 0.2mm, the tilt angle can reach 30~35°. When the change of the tilt angle of the side face stays in this scope, it is not necessary to add a sustentation, but molding directly.