Abstract

Metal additive manufacturing (AM), also known as metal 3D printing, is a challenging process to be controlled for desirable outcome due to its many process parameters. Residual stresses or deformations may occur in an AM manufactured part because of rapid heating and cooling cycles in the layers. The effect of process-controlled parameters in laser powder bed fusion (L-PBF) on deformations of a manufactured part has not been well examined and reported only sparely in literature. The objectives of this paper are: to study deformation behavior of a L-PBF printed part using finite element method, to perform parametric study of process input variables by changing few selected process parameters in the simulations, and to attempt identifying optimal values within the studied range of selected parameters to minimize part distortion. In this study, the material used for the heat sink finite element model was Inconel 718 which is commonly found in AM manufactured parts. ANSYS finite element program was employed to simulate a heat sink fabrication. The finished dimensions of the heat sink model were 12 mm in height, 26 mm in width, and 26 mm in depth. Thermal-mechanical sequential coupling approach was employed to simulate layer-by-layer built up process. The resulting deformations was evaluated by varying laser travel speed, base plate temperature, and initial layer angle. The maximum deformation (distortion) was observed at the corners of the heat sink model upon release from the base plate and found to be approximately 0.115 mm. Based on this study, the relative optimal simulation results for minimum distortion for selected parameters were 600 °K base plate temperature, 600 mm/sec speed of laser, and 0° initial layer angle. These results can be served as foundation for further study of varying other L-PBF process parameters.

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