1. Scope

Keywords

Rationale

In the foundry field, additive manufacturing (AM)-made sand moulds and cores contribute to improving the functionality of sand moulds and to create more complex and highly functional casting products. Having moulds and cores with appropriate gas permeability is an important factor to be considered in the casting process and in mould design to avoid gas defects and misruns in castings. In a conventionally made sand mould, gas permeability is controlled by changing the grain size distribution of the sand. Conversely, in AM-made sand moulds and cores, grain size distribution is optimized on AM machines, and it is difficult to change grain size distribution to control gas permeability. AM-made sand mould designers are required to design a structure that has sufficient strength to prevent breakage in the casting process, while allowing for appropriate gas permeability through thin wall and inner structures. This project provides a test method for the gas permeability of AM-made sand moulds and cores designed with internal structures. There is no international standard for testing gas permeability of sand moulds for metal casting, although some standardized test methods for conventionally made sand mould have been locally used in AFS (American Foundry Society) in United States of America, JACT(Japanese Association of Casting Technology) in Japan, and so on. The result of this project enhances the comparability of different machines, sands and binders. The proposed data can serve as basic data for design the AM-made sand mould and information to be shared between customer and manufacturer.