Non-sand core for casting or moulding - used in prodn. of metal, plastic or ceramic article with cavity and undercut or recessed section

摘要

A core, for use in a mould for producing an article with one or more cavities and an undercut or recessed cross-section, is made of material other than sand. Suitable core materials include thermoplastic resins (polyfluoroethylene, polyimide, polyamideimide, polysulphone, polyamide, polypropylene, poly-ethylene or polyester), silicone resin and rubbers (natural or synthetic rubber, silicone rubber or fluorine-contg. rubber). USE/ADVANTAGE - In the prodn. of metal articles by pressure die casting, gravity casting, low pressure casting precision casting etc. and for prodn. of plastic or ceramic articles by injection moulding. Compared with a sand core, the new core can be produced easily, rapidly and inexpensively, is easy to handle, contains no contaminating constituents, has high strength facilitating prodn. of cavities or undercut or recessed sections, has a combination of compressive strength during casting and breakdown properties after casting, contains no difficultly disposable constituents (e.g. binder) and can easily be reused without expensive treatment.