| 摘要 |
PURPOSE:To obtain a casting method with which the cost of manufacturing a casting mold is relatively low and which can decrease casting defects and improve dimensional accuracy in the casting method which pours a molten metal into a sand mold having air permeability while evacuating and sucking the air from the outside of the mold. CONSTITUTION:A sintered metallic pattern 1 having air premeability is contained in a box body 2 and the box is hermetically closed by a cap 4 having an aperture in the position corresponding to the sprue 3 of the pattern 1. The body 2 has a duct 5 communicating with a gas evacuating section and while the inside of the body 2 is maintained under the negative pressure, the molten metal is poured into the pattern 1. Since the casting mold has high strength according to such method, the production of not only thin-walled and small-sized articles but also thick-walled articles is made possible and since the pattern 1 having an optional shape can be manufactured by molding the same by a press die and sintering the molding, the cost of manufacturing the metallic pattern is low. The improvement in the dimensional accuracy and the prevention of casting defects are attained as well. |
