The Research Of The Process And The Key Technology Of Selective Laser Sintering

At home and abroad, the research and development of the technology of Selective Laser Sintering (SLS) is always one of the most important research directions in the field of Rapid Prototyping (RP). Judging from the current situation and the existing problems of SLS, the development of the sintered materials and the study of its sintering characteristics will be core in the recent research and will last hot. While the hot research of this point, the further study of sintering technology of existing powders is neglected more or less. As to the SLS using PS powder, which is applied most widely and maturely, there are still relatively serious precision problems in the shape and size of the sintering components. So the systematic analysis of the SLS process parameters, especially the temperature control in the sintering process and the reasonable post-processing techniques, the improvement of the prototype's shape and size accuracy which can further enhance its performance will do much good to meet the SLS application requirement and extend the application scope.This paper focuses on the studies of SLS technology and a number of key technologies, including the studies of impact of the process parameters on the quality and the forming efficiency, temperature control technology, post-processing technology and its applications in the medical field.Firstly, this paper introduced the basic principles, the applications and the classification of the rapid prototyping; introduced the basic principles and the process of SLS in details. All of these introductions provided a theoretical basis to the study of the subject.Secondly, this paper analyzed the influence of SLS process parameters on the quality of the parts. The effect of certain process parameters, including the laser power, scanning speed, sintering spacing, layer thickness and scanning mode, on the quality and efficiency of molding has been studied by experiments, and the effect rules has been provided. The optimal allocation of the parameters has been given by integrating the effects of process parameters on the molding quality and efficiency.Using the basic theory of heat transfer, energy transfer process of SLS technology has been analyzed. The distribution of the laser power and the process of the sintering have been studied. And a set of PS powder laser sintering temperature control strategy has been given.Then, two post-processing techniques aimed at different application of SLS have been introduced, which include resin infiltration and wax infiltration. These two technologies respectively focus on functional prototype component and melt mold casting vanishing mold. According to the research, the paper pointed out what should be paid attention to in the process of component cleaning, infiltration process and post-infiltrating treatment of these two technologies. The partition-joint molding method for large parts has been designed and studied. The results of the experiments show that the inserting structure suits to the circle section components and the cross-split structure suits to non-circle section components.Finally, an example has been investigated to illustrate the application of the SLS technology in bone-repairing surgery. The method of treating the CT data using the software Mimics has been introduced; then, the related issues in medical model sintering has been investigated using a bone-repairing surgery, such as the technologies of the allocation of sintering parameters, the post-processing and the other technologies related.