Nylon Sls Rapid Prototyping Technology Research

Rapid Prototyping (RP) is an advanced manufacturing technology that has been drawing attention of researchers and manufactures in recent years. RP is a integrated process of many technologies, such as information technology, computer science, CAD/CAM, laser technology, material science and so on. One of the most widely used methods of RP in the world is Selective Laser Sintering (SLS). Based on a given SLS system, it is an important subject for developing SLS technology to develop new high-performance materials and it's SLS technology, improve prototyping efficiency and accuracy, amending the using properties of SLS prototyping, and extend the utilization area of SLS prototyping. In this dissertation, using AFS320-MZ/Q SLS system as the main experiment equipment, aiming to develop new high-performance polyamide (PA) for SLS which has reach international level, the SLS technology of indigenous PA material of PA1212 has been studied in detail.Firstly, the interactions between laser and PA during the SLS process are analyzed. The prototyping mechanism of rapid prototyping of PA during the SLS process is studied by combining with traditional powder sintering mechanism and SLS fabrication characterization of thermoplastic. The mechanisms of shrinkage and distortion during SLS of PA are also discussed. Composition of SLS shrinkage, computation, and the relationships between shrinkage and process parameters are discussed. After the prime cause and developing trend of distortion are illustrated, its solving measurements are proposed. All factors affecting SLS quality and their levels are intensively analyzed.Secondly, considering the advantages and disadvantages of SLS fabrication of thermoplastic and PA, materials and schemes to experiment are designed. Experimental materials are comprised of matrix materials and additional materials. Homemade PA 1212 is used as matrix materials and talcum powder, calcium carbonate (lightweight calcium carbonate), activated lightweight calcium carbonate, activated wollastonite, crystallite and PA 66 are selected as additional materials. Experimental materials are confected through the methods of physical blending and chemical modification, and a primary study on modified materials is carried ·out. Schemes to experiment are designed by choosing the primary affecting factors.Lastly, the prototyping performances of designed materials are studied through a lot of SLS experiments according to the designed schemes to experiment. Differences of SLSperformances of before and after modification are analyzed and compared, and modification mechanism of fillers is discussed. For the materials of physical blending, effects of modification materials aren't obvious except 3-5# composite filling with talcum powder, and the strengths of materials fall down with the addition of fillers. The best modification effect is gained by chemical method called as co-polymerization. Detailed analyses are carried out on process parameters affecting SLS quality, which include preheat temperature, laser power and scanning speed. The single and synthesized rules of effect of those parameters on SLS quality are studied, and the SLS parameters criterions of co-polymerized PA are elementally optimized through the orthogonal experiments.