3D Finite Element Simulation Of Selective Laser Sintering Process

Selective laser sintering (SLS) is one kind of rapid prototyping (RP) technology, which uses a laser to sinter powdery material selectively to produce three-dimensional mechanical parts. It can shorten the design and manufacturing cycle, hence reduce the production cost and increase the competitiveness of new products. SLS is a thermal process, creating layers by a scanning infrared laser beam melting powder. Each layer is drawn on the part cylinder using the laser to sinter the material then the part bed is lowered and powder-feeding cartridge rose, keeping on sinter, the end, the sintered layers form the part.The layer by layer building process introduces an error which affects the dimensional accuracy as well as the surface finish. As a thermal process, this will unavoidably be accompanied by material shrinkage. The shrinkage is the result of thermal and phase change effects. The thermal problem is dominant, the temperature field is complicated, thus, the non-uniform distribution of temperature field brings stress and distortions of parts produced. To the phenomena, at present, most of the research methods on SLS process are experimental and the fixed offset values are applied. This method can not improve the efficiently the dimensional accuracy.Based on the above-mentioned problem, a finite element simulation is carried out in order to predict the plane shrink by calculating plane stress and plane strain in the SLS process using a pulsed laser. ANSYS is the available FEM (the finite element method) commercial software. ANSYS is widely utilized in many fields. To thermal field, ANSYS can highly approach nonlinear transient heat conduction problem. A transient thermal analysis calculates the temperature distribution and related thermal quantities in a system or component. as knowing the temperature distribution ,by experimental verifying. Then, on the thermal analysis basis, simulation stress field. By ANSYS simulation, attain distortion amount, then, by optimizing scan path to improve the part precision.To achieve these, it need use ANSYS' APDL (ANSYS Parametric Design Language) to compile program to apply load of moving heat source, chooses suitable time step, and uses the method of "birth and death" method to simulate the sinter process. the article analyze some key promlems in 3-D finite element simulation of laser sinter forming based on ANSYS from the element models and models foundation,disposing and loading of laser impulse and boundary condition. Through simulation, this paper establishes a feasible dynamic simulation method on 3D SLS temperature field, stress and deformation, which can instruct improves of the part precision, accelerate the applications of rapid prototyping technology, and provide theory foundation and instruction, promotes the application of FEM (Finite Element Method) on rapid prototyping technology analysis.