Experimental Research Of Laser Micro-Fabrication With Metal Powder

MEMS technology develops quickly these years, and making micro metal objects by laser acting on powder materials is a hot topic. Laser micro-fabrication with metal powder has great advantage than with the non-metal powder. High quality micro objects can be made by this technology, and the processing time between raw materials to final objects is greatly reduced. So laser micro-fabrication with powder materials has got great attention in recent years. There are many ways for laser micro-fabrication. In this dissertation, fundamental research of laser micro-fabrication is carried out by taking the selective laser sintering technology. The principle of laser acting on powder materials is studied. The quality of the final objects made by laser micro-fabrication is influenced by many factors. The change of each factor will greatly affect the experiment result. The author analyzes the influence of each factor's change on the experiment result. By taking orthogonal experiment, the degree of each factor's influence was pointed out. Furthermore , the author analyzes the processing parameters'influence on laser micro-fabrication from the change of laser wavelength scanning velocity grain size of powder and laser energy intensity. The fabrication result varies with the change of experimental powder and laser wavelength. Different powder(Ni Fe Al and Sn powder)and lasers(CO₂ laser and fibre laser) were adopted in laser micro-fabrication experiment. The experiment results were analyzed by comparing with each other. Fibre laser can have a less focusing spot size than CO₂ laser due to the shorter wavelength. Furthermore metal powders have a higher absorptivity to fibre laser than CO₂ laser. For laser micro-fabrication, a continuing laser output or high output frequency is indispensable. A low output frequency will cause the powder to be splashed, so the powder cannot be melted. By comparing the experiments carried out, we found Fe powder has a better result. For other three powders, there are fierce balling phenomena in the experiments. Sub-nano powder will burn spontaneously in the air. Even the powder fabrication was protected by gas Ar, the fabricating result is still not good due to the...