Research On Structure Improvement Design And Forming Quality Of Metal Powder SLS Printer

Selective laser sintering(SLS)printing technology is an advanced rapid manufacturing technology,The SLS printing technology of metal powder has been studied both at home and abroad.However,there are still some gaps between domestic and foreign research.The structure of metal SLS printer and the influence factors of forming quality were studied in this paper.The goal of the research is to improve the structure of metal SLS printer and improve the quality of the molded parts.The overall structure of the printer is designed,in view of the present situation that the existing powder delivery device can't overcome the influence of “spheroidization and splashing” in the forming process,the powder delivery device was improved,a layer of hard rubber was added on the surface of the powder roller and a certain thickness scraper was arranged before the powder roller.The parts were machined and the prototype of the printer was assembled,the test was carried out on the prototype printer by using the unimproved and improved powder delivery device respectively,the results show that the improved device can ease the phenomenon of “spheroidization and splashing” and improve the forming quality.The dimensional accuracy of the test sample was analyzed,the actual size and theoretical size have some deviations,so it is necessary to study the influencing factors of the forming quality so as to improve the forming quality.The effects of geometric data processing,powder material properties,forming process parameters and scanning mode on the forming quality were discussed,suggestions on the selection of parameters were given.The evaluation of the forming quality was studied,in view of the fact that there is no test piece to reflect the quality of molded parts comprehensively,a kind of test piece which can evaluate the forming quality of the molded parts more comprehensively was designed,the design of the test piece provide a reference for the formulation of a reasonable quality evaluation model and lay the foundation for a comprehensive and systematic evaluation of forming quality.In view of the present situation that the research on three-dimensional sintering temperature field of metal powder is not much,the numerical simulation of the three-dimensional transient temperature field of metal powder was carried out by using water atomized iron powder as the research object,the analysis of the result was helpful to master the dynamic distribution of temperature field during sintering process,the technological factors influencing the forming quality were analyzed by changing the sintering parameters which can make theoretical guidance to the actual experiment and provide the theoretical basis.In summary,the development of this topic on the metal SLS printing technology laid a certain theoretical and technical basis for its further study.