| 摘要 |
<p>PURPOSE:To pack mixed sand to a high density and readily and surely produce the mold having a required strength by passing compressed air in the mixed sand. CONSTITUTION:Mixed sand 30 is charged into the spacing formed by a pattern plate 1, flask 6 and build-up flask 7 and compressed air is supplied from air feed port 13 into a cover member 8 by opening a gate valve 16. The compressed air passes through the small-diameter holes 12, 12 of a squeeze plate 11, its outside circumference and the inside surface of the cover member 8, then flows through the inside of the mixed sand 30 in the build-up flask 7 and flask 6, subsequently passes through vent plugs 5, 5, small holes 4, 4, recess 23 and through-hole 24 and is exhausted to the atmosphere. As a result of this, the mixed sand 30 is packed to a high-density state. Thence, a cylinder 9 is operated to lower the squeeze plate 11 and compress and raise the mixed sand 30, after which the gate valve 20 is opened for the specified time to supply the heated low-pressure compressed air to the inside of the cover member 8 through exhaust port 13. The moisture in the mixed sand 30 is evaporated away and the sand particles are firmly bonded by water-soluble binders. The flask 6 built therein with the mixed sand 30 is parted on a conveyor and the above operations are repeated, whereby the molds are molded continuously.</p> |
