The Research And Development Of Laser Scan Path Of Selective Laser Sintering Process

Laser is used to sinter the Selective laser sintering (SLS) parts. The scanning system needs to do plenty of scan, so scan method is very important to SLS process. Efficient scan method can minimize the SLS parts' shrinkage, increase the precision and strength of the SLS parts, improve the fabrication productivity of the SLS machine, and increase of the laser–galvanometer's service life.The character of the scan method currently used in SLS process is investigated in this dissertation. In order to solve the unreasonable grouping scan method in HRPS series, which are made by the Rapid Manufacturing Center of Huazhong University of Science and Technology, an improved grouping scan method is developed. This new method can enhance the strength of the parts, increase scanning efficiency, shorten fabrication time, increase of the laser service life and improve the smoothness of the parts' surface. But this scan method cannot meet the request of high precision, so another scan method (compound scan method) is developed.The compound scan method utilized the precision of contour scan method and the quickness of the improved grouping one. It overcomes the shortcoming of the slowness and instability in contour offset and the coarseness in improved grouping scan method. Further more, many other problems have been solved, such as laser power matching and laser rate matching in the path generation, so the compound scan method can be successfully used to the SLS machine.The results of the experiment indicate that the fabrication efficiency and strength of SLS parts fabricated with the improved grouping scan method are the highest among all the scan method researched in the dissertation. And the maximal error of the parts scanned with the compound scan method is doubled than this of the parts scanned with other scan methods. The flexual strength increase of eighty percent, and the tensile and impact strength are increased too.