| 摘要 |
PURPOSE:To spread silica sand to all the narrow parts of a prototype and to cast a product having high quality by charging the expendable prototype and silica sand into a molding flask body and supplying high-pressure air into the molding flask body while oscillating said body, then reducing the pressure therein. CONSTITUTION:The silica sand 13 is supplied and packed into the prototype body 7 while the expendable prototype 14 and the prototype 15 for a riser and held in the prescribed position in the molding flask body 7. A sand stopping flask 8 is then fixed onto the molding flask body 7 and chorus motors 24 are started to oscillated the entire part of the molding flask 1; at the same time, the high-pressure air is blown into a wind box 5 by using a stop valve 20. The high-pressure air enters the inside of the silica sand 13 by passing the holes 19a, 17a of upper and lower perforated plates 19, 17 and the spaces among the fibers of a compressed wool board 18 to form the fluidized layer of the silica sand 13 by which the silica sand 13 is spread to the narrow parts of the prototype 14. The stop valve 20 is then closed and a stop valve 22 is opened to suck the air through a partition plate 16 by which the pressure in the molding flask body 7 is reduced. The silica sand 13 is thoroughly spread to the narrow parts of the prototype 14 by the oscillation and pressure reduction to fix the prototype 14 in the prescribed position. The pressure reduction is further continued and the oscillation is stopped, then the molten metal is poured into the prototype 14.
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