The Technological Process of Obtaining Sand-Plaster Molds for Complex Thin-Walled Aluminum Castings

Abstract

The aim of the research is to develop a technology for the preparation and drying of moulds and cores based on sand-plaster mixtures, which allows obtaining exact details of a complex form of required quality. The levels of the basic properties of sand-plaster moulds and cores – strength, durability, gas permeability, friability – making up the quality of a casting have been determined in the research paper. Mathematical patterns of the properties of the moulding mixture on the basis of plaster have been developed. The composition of the mixture satisfying the requirements of the quality of castings has been determined experimentally with the use of multifactorial optimization methods. The research studies of the process of plaster mould drying have been done, and the technological process of mould drying has been developed using a microwave machine. Manufactured cores and moulds have not only possessed high strength properties but also have allowed escaping from such defects as gas holes in die castings (castings). The proposed mode of drying can reduce the drying time by 40–50% and reduce costs by 30–70% depending on the size of the core.