Study Of Stress And Deformation For Multilayer Of PA6Powder In Selective Laser Sintering

The Selective Laser Sintering is one of Rapid Prototyping which based on manufacturing layer by layer. It has many advantages compared to other RP technologies, such as a large variety of molding materials, no special support for cavities and cantilever structures, can fabricate complex parts. After twenty years of research, it has been gradually used in the automotive industry, mold manufacturing, biomedical and other fields, which make this technology receives a lot of attention and development at home and abroad.The forming process of selective laser sintering is the laser scan the surface of powder in computer-controlled path, and sintered powders melted into lines, lines agglutinate together to form layers, and the stacked layers build the3D parts. The uneven temperature field and the high shrinkage of polymer materials such as PA6lead to a big stress and deformation of the molding process. Deformation will affect the molding precision and a large stress will lead to crack initiation, which seriously affect performance of parts.Therefore, it is necessary to study the stress and deformation of PA6powder sintered parts in-depth and enhance the practicality of sintered parts, In this paper, a new volume heat source is proposed by analyzing the laser thermal effect between the laser and the powder bed, developed the temperature and stress field for multilayer of PA6powder in selective laser sintering and the influence of process parameters on stress and deformation combined with numerical finite element method. And then study and optimize the process by theoretical and experimental methods.First, the temperature field of the multilayer sintering process has been researched. Simulating the additional material manufacturing process by way of birth-death element in ANSYS to obtain the temperature field changes in the sintering process and analyze the impact of preheating temperature forming part of a three-dimensional solid condition.Second, the stress field of multilayer sintering process has been studied based on the temperature field analysis. By the basic principles of thermoelasticity, turn the influence of temperature in sintering process to strain and stress of the sintered pares, and get the evolution of stress field.Third, perform the experiment of multilayer sintering and measure the stress of sintered parts. The stress is obtained by elastic deformation of the sintered parts occur in the stress release effection based on the method of elastic deformation. And then Optimization of process to get a better part with small deformation combined with the results of simulation calculations,.Through a series of work in this paper, studied the evolution of the stress and deformation in sintering process and optimized the sintering process parameters, get a good three-dimensional solid structures. The measurement and research PA6material sintered parts can also play a consideration for the other polymer powder materials in SLS.