Apparatus and method for sequentially feeding quantities of sand into a mold space and subjecting the space to evacuation and then pressure increase after each feed

摘要

A first quantity of all the molding sand necessary to produce a mold is fed in the mold space, the first quantity being one of at least two parts divided from the total molding sand. The mold space is evacuated and then air is introduced into the mold space at the air- pressure rising rate of 30--to 500 kg/cm.sup.2 /sec. Another quantity of the molding sand is fed into the mold space, the mold space is evacuated and then air is introduced into the mold space at the air-pressure rising rate of 30--to 500 kg/cm.sup.2 /sec. The apparatus includes a sand passage through which each quantity of sand is fed into the mold space, and a gate for closing the sand passage thereby closing the mold space to allow the mold space to be evacuated and then subjected to a pressure increase.