Comparative evaluation of insulation cotton configurations on the investment casting quality of industrial valve parts

This study contributed to the comparison of insulation cotton configurations for the investment casting quality of industrial valve parts. Due to the complexity, parts of industrial valve bodies are usually produced by casting. However, the investment casting production process has several problems, such as shrinkage porosity. Currently, the investment casting industry uses cotton configuration to solve the problem of shrinkage porosity. Therefore, this study compared three cotton installation treatments in the mold shell to determine the optimal use of cotton. There are three schemes of the type of cotton installation on the shell that will be observed, including the triangular insulation cotton area denoted as case A installed 55-mm and case B installed 90-mm cotton on the right and left sides, and case C denoted with adding bracket arms on the upper side. In this study, we used RMM (retained melt modulus) and the finite element model to analyze the shrinkage porosity's location and to monitor the porosity that occurred during the solidification process. The result showed that cotton could reduce shrinkage porosity by 3.30%, 1.95%, and 1.47% for case A, case B, and case C, respectively. Therefore, the best alternative is case C, add the cotton and bracket arm on the upper side, which is the optimal strategy to prevent shrinkage porosity.