Design and Optimization of gating and feeding system through simulation technique of Steel Impeller to avoid existing casting defects

Abstract

Casting is a manufacturing process to make complex shapes of metal materials; during mass production, we may experience many defects, such as gas porosity, pin holes, blow holes, shrinkages and incomplete filling that may occur in sand casting. Porosity is one of the defects most frequently encountered in Steel casting. Porosity impacts cost by scrap loss and limits the use of cast parts in critical high strength applications. The amount of porosity is closely related to the parameter of sand casting process. The gating/riser system design plays a very important role for improving casting quality. The main objectives were to study the existing design of gating and feeding system using ESI Pro-CAST casting simulation software, to prepare the sand mold and cast the part, to compare the simulated result and experimental results, and to reduce rejection rate and to enable the company to again start the mass production. Using L9 array method certain experimental parameters were define and casting has been done. Each experiment was repeated thrice to get the parameters accurate. After getting all these results we have finalized the ideal parameters to get impeller without any Shrinkage porosity, Misrun and minute blowhole. The results that were received by simulation software precisely matches with the results at hand. Most problematic issue was the rejection of casted part and the reduction of foundry production. The problem was highlighted because neither a single part would comply for the machining without any rework that includes welding, grinding etc. The rejection percentage of this part was around 60%. Effort has been made and we have successfully identified the basic and precise amount of attribute that were considered during the experimentation process.