Effect of Bottom Gating Filling System Design on the Initial Stage of Mold Filling: A Parametric Study.

While the filling stage has the least time during the metal casting process, its influence on the casting quality can be remarkable. In gravity casting, the design and dimensions of the filling system determine the filling rate, metal velocity, and the possibility of surface turbulence, where the reliability of casting is mainly impressed by these parameters. In this study, finding an appropriate filling system for a hollow cylinder is examined by investigating the effect of the ingate size, shape, and geometry on the flow characteristics of the molten metal. Simulations are performed investigating the initial filling stages and their repercussions. Three different bottom-gating filling systems are proposed with rectangular, fan, and ring ingate shapes. To compare the filling pattern, metal velocity, and air entrainment of three different filling systems, ProCAST, a CFD simulation software, is used. Results indicated that fan ingate shape successfully introduced less turbulent flow than rectangular ingate shape, causing a reduction in air entrainment. Moreover, results showed that using ring ingate, with sufficient total ingate cross section and taking advantage of the uphill metal flow, can reduce metal velocity entering the cavity as well as eliminate air entrainment. [ABSTRACT FROM AUTHOR]