UBC Theses and Dissertations
Experimental and numerical investigation of the effect of block-type support structure design on the thermal field within components fabricated by selective laser melting Khobzi, Arman
The successful production of overhang features in the Selective Laser Melting (SLM) process requires additional structures, known as “support structures”. These structures provide mechanical support to overhang features and alter thermal fields within the produced components. Hence, the design of support structures impacts the development of in-situ thermal stress and component deformation. The present research combines experiments and numerical modelling to quantify the contribution of the support structure to the evolution of the thermal field in a cantilevered plate and, in turn, to investigate the relative role of heat transfer on component deformation. Series of build experiments were undertaken to investigate the effect of block-type support structure design on the deformation of the cantilevered plate. Two block-type support structures were designed for the overhang platform of a cantilevered plate. The designed samples were manufactured using SLM®500 machine located at Singapore Centre for 3-D Printing. The deformation of the overhang platform was measured using the Image Analysis technique. Next, a statistical analysis was performed to evaluate the relative impact of each design parameter on component deformation. Finally, a 2-D transient heat transfer model using the “layer agglomeration” approach was developed in the commercial package “ABAQUS” to perform a sensitivity analysis to investigate the impact of design parameters on heat transfer and the evolution of the thermal field in the support structure and the cantilevered plate. Numerical results demonstrated that the total contact area of teeth and the total support base area alter thermal fields within the produced components. It was predicted that increasing the area for conducting heat to the base reduces the peak temperature in the platform. Additionally, the vertical temperature gradient within the overhang platform decreased by increasing the total contact area of teeth. Moreover, increasing the total contact area of teeth produces a more uniform temperature field within the overhang platform, while the total base area was found to have a negligible impact on it. Also, the experimental case study was analyzed with the numerical thermal model suggested that the vertical temperature gradient and the peak temperature were reduced in the sample showing a lower amount of deformation.
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