Effect of temperature and pressure on shrinkage in wax injection molding

Abstract

In precision casting, many model materials can be used to make complex, accurately sized molds. Model material is an important key for successful production. Wax models are widely used in model manufacturing because they allow economical production. In the wax injection method, some undesirable situations occur during the production of the model such as shrinkage, collapse, warpage, weld marks, surface defects, air marks, and burr formation that the manufacturer does not want. In this study, it is aimed to examine the effect of temperature and pressure parameters on shrinkage of the wax model in injection molding. The study was carried out at wax temperatures of 65 °C, 70 °C, and 75 °C and injection pressures of 0.1 MPa, 0.15 MPa, 0.2 MPa, and 0.25 MPa. In the experiments, the flow of the parts was observed during the filling of the plexiglass mold, and the shrinkage ratio of the obtained wax model was determined and evaluated. It is assigned that some of factors which affect quality of the final product produced by investment casting method are product shrinkage and surface quality of wax model.