Investigation of optimum gating system design of fused deposition modeling pattern for sand casting

Abstract

Sand casting is one of the major processes in manufacturing industries today. Inappropriate sand casting mould design have led to casting defects and increased the rejection counts. Therefore, this paper examines the feasibility of producing sand casting pattern with Fused Deposition Modeling (FDM) system. FDM is one of additive manufacturing processes that enable the fast, flexible and cost-effective production of sand casting pattern. However, one of the important factors for a good casting quality is the gating system design. Hence, three concepts of gating system were CAD-designed and analysed in this research in order to obtain the optimum design of sand casting mould. The first concept was designed with sprue and riser at both opposite sides, second concept with sprue at the side while riser was placed at the middle top and third concept with sprue and riser both at the middle top. In order to select the best design concept, ANSYS software was chosen. From the simulation result, Concept 1b was selected as the optimum design of gating system design with the highest ranking score based on the criteria; static pressure, density, velocity magnitude, total temperature, internal energy, turbulent viscosity, wall shear stress and velocity streamline. Lastly, an actual sand casting process produced a hand wheel pattern and the results were validated. A comparison made was based on the highest score Concept 1b (sprue/30mm and riser/30mm opposite side) and lowest score Concept 3c (sprue inlet/30mm, sprue outlet/10mm and riser/10mm at middle top) and It showed that Concept 1b provides a better quality in terms of dimensional accuracy and surface finish compared to the other concepts.