| 摘要 |
The present invention relates, in general, to a low pressure casting method and apparatus and, more particularly, to a low pressure casting method and apparatus intended to shorten a time period required to cast molten metal into a molding cavity of a mold and then to allow the molten metal to be solidified in order to maximize productivity, and intended to cause a solidification progress to be uniform and rapid to improve mechanical properties of molded products resulting in maximization of their commercial value.An object of the invention is achieved by a low pressure casting method and apparatus adapted to cast molten metal received in a molten-metal holding furnace (20) into a molding cavity (15) of a mold (10) through riser tubes (30) at low pressure and then to solidiy the molten metal, including the steps of: preparing a mold (10) having a molding cavity (15) communicated to runners (40) via a plurality of branch gates (42); casting molten metal received in a molten-metal holding furnace (20) into the runners (40) through riser tubes (30); and casting the molten metal cast in the runners (40) through a plurality of branch gates (42) into the molding cavity (15) of the mold (10). The present invention is capable of shortening time for production of molded products to maximize productivity by preventing overheating of casting openings owning to flow of molten metal concentrated thereto and by lowering temperature of molten metal by shortened flowing distance of molten metal. Furthermore, defects of molded products are reduced due to uniform and rapid solidification of molten metal, and reliability of molded products is maximized due to fine grain crystals thereof. |
