An optimization method of gating system for impeller by RSM and simulation in investment casting

The design of gating system occupies a very important proportion in the design of the entire casting process. Casting solidification simulation is being a deterministic approach replacing the iterative trial and error method to design gating system in investment casting. However, the experience and knowledge of the engineer have an important impact on the effectiveness to achieving an optimal solution. The purpose of this paper is to get an optimized gating system to decreasing the size of the riser with a safety margin design with no shrinkage cavities and porosities in the impeller. The Box-Behnken Design (BBD) was prepared with three experimental factors and two optimal targets. The experimental factors involved gating system diameter, gating system height, and pouring temperature for open impeller. The targets included volume of shrinkage porosity and distance from shrinkage porosity to casting. The results indicated that the diameter of the riser has the most obvious impact on the volume and position of the shrinkage porosity. Compared with the riser obtained by the modulus method, the results show that the effect of riser optimization is more obvious, the volume of gating system is reduced by 47.85%, and the casting yield is increased by 15.02%. The physical experiments were performed to verify the simulation results, and good agreement between experimental values.