Effect of feed sprue size on porosity defects in Platinum 950 centrifugal investment casting via numerical modelling

Abstract

Abstract The centrifugal investment casting process is typically used in the jewelry manufacturing industry. However, porosity defects are often found in jewelry castings made by this process. Porosity on the casting surface is a major concern for jewelry manufacturers as the defect leads to significant yield losses during the repair work. Improper feed sprue design is one of the major causes of porosity defects. The purpose of this work is to study the effect of feed sprue size on porosity defects in Platinum 950 jewelry made by the centrifugal investment casting process. Two feed sprue sizes were experimented in this study. FLOW-3D CAST software was employed for the casting process simulation. Simulation results were analysed together with experimental results quantified by an image analysis technique. The results show that the larger feed sprue provides castings with less porosity compared to the smaller feed sprue.