The Experiment Research Of Selective Laser Melting Of Metal Powder

Selective Laser Melting (SLM) is a novel method of rapid prototyping (RP), which is to melt metal powders layer after layer by laser beam to form a metallurgical compact entity. It takes advantage of selective laser sintering and laser cladding technology. High quality alloy or single metal objects can be made with high precision and low coarseness.The principle of laser acting on metal powder material is the foundation of SLM. Fundament research of laser energy transfer in the metal powder is carried out to get the mechanics of SLM which is melting-freezing. Spheroidization is the key element for SLM.The processing parameter is the key element of SLM. Fiber laser has high quantity laser beam and focusing ability, so it is the first choice for SLM. A resonale pattern of pave powder and gas protect device is needed. The thickness must beyongd the laser beam's enengy so that so that the basement can fuse with the new layer. Furthermore, the author analyzes the processing parameters influence on SLM from the enengyr of laser, scanning velocity and the distance of laser scanning, figure out that the phe phenomenon of oxygenize is the chief vice elements in SLM.Metal powders with high laser energy will boiloff. Using this phenomenon can make high depth-to-width ratio metal thin wall. Double side scanning can improve the quality of metal thin wall. Scanning rate is very important is this process, high speed will cause the metal powder splash. From lager quantity experiment we get a critical speed wich is unlimited by laser power. Beyond this speed metal powde do not splash.Frabrication of functional gradient material with laser technology is a hot topic of laser rapid prototyping. The article contrast different technics of fabricating functional gradient material. The method of laser boil away metal powders was used to make iron-nickel sandwich structure structure.