The Experiment Research Of Nylon Composites Powder Laser Sintering

Select laser sintering is an important branch of rapid prototyping and it becomes an important development direction of advanced manufacturing increasingly. It improves the production flexibility because of needing no any dies&tools, being unrestricted un-restricted by shape of part geometry, and higher material utilization, shorter life cycle and so on. Based on a given facility, it is an important direction of developing SLS technology to develop new high-performance materials, improve sintered parts efficiency and accuracy, amend the using properties of SLS prototyping and extend the utilization area.At present, Selective Laser Sintering of nylon composites is the focus in the world. The parts which are made in Selective Laser Sintering of nylon composites have high intensity, elasticity and endurance and suit the urgent assembly and the function test. However, domestic study on the technology of Selective Laser Sintering of nylon composites also just starts, It also remains a lot to be studied in sintering technology.The temperature field bring stress and distortions of parts which is complicated. In order to solve this problems, a finite element simulation is carried out. Temperature distribution of SLS is achieved by simulation on ANSYS.The traditional nylon powder always brings about heavy shrinking and bending in the process of sintering which can not meet the using demand. Therefore, the purpose of the article is to produce nylon composite powder with high performance which is suitable for selective laser sintering. The content and results of the article as follows:The process which sintered with nylon composites powder is simulated by ANSYS. The finite element model is built as in fact when thermal conduction, thermal convection, thermal radiation, phase-change latent heat and material nonlinearity are considered. APDL language is used to promote the movement of laser and the technique of birth/death element is introduced in multi-layers sintering simulation. Thermal distribution is investigated, the feature of multi-layers is analyzed, the best scanning interval is 0.15mm, the best powder bed depth is 0.15mm. The simulation results are contrasted with experiment results and the simulation results agree with the experimental results well.Optimum technological parameters of different proportion of high density polyethylene in nylon composites are obtained by orthogonal test. Mechanical properties of sintered parts are compared under the optimum parameters. As a result, elastic modulus and ultimate strength decreased first and then increased. The reason of shrinkage and warping is analyzed and the effect of process parameters and the causation of secondary sintering are discussed. It is analyzed that the effect of preheating, laser energy density or material properties to the secondary sintering.