Modelling, simulation and experimental validation of heat transfer in selective laser melting of the polymeric material PA12

One of the most promising additive manufacturing techniques is selective laser melting of semi-crystalline thermoplastic powders. In this process the powder is fused in defined, locally-restricted points in the current powder layer by the energy input of a laser beam and, thereby, bonded to the already fused material of previous layers. In this way geometrically complex parts are constructed layer-by-layer. The accuracy of the process and the properties of the resulting parts depend on numerous process parameters and their interactions. To improve the process strategy and to reduce, e.g. eigenstresses and warpage a thorough understanding of the influence of various process parameters is required. In the present contribution one step in this direction is done by analysing the laser energy input into a powder bulk for different process parameters by comparing temperature distributions and the size of melting pools. Experiments with single-line specimens are conducted, analysed and compared to numerical results from finite element simulations of the highly nonlinear thermal problem.