GYPSUM MOLD FOR VACUUM CASTING

摘要

PURPOSE:To obtain good run and a defectless product without casting defects by providing a filter made of a refractory material having better air permeability than gypsum from the part near the final filling part of the molten metal in the product cavity to the outside surface of a gypsum mold for casting. CONSTITUTION:A filter 5 formed of a refractory material is directly communicated with and provided to the neighborhood of the part in a product cavity 3 where a molten metal is finally filled. The filter 5 is required to have better air permeability than gypsum and is formed preferably of a refractory material. A sand mold or porous zirconia sintered body or the like is usable as the filter 5 meeting such requirements.