| 摘要 |
<p>PURPOSE:To mold the packing materials of the entire part in a molding flask into a mold having uniform hardness by increasing the ventilation resistance of the packing material thereby blowing compressed air. CONSTITUTION:A packing material 9 is charged into a space formed by a pattern plate 5 and a molding flask 7 and the top surface of the flask 7 is airtightly closed by a cover member 9, thence stop valves 15, 16 are opened to supply compressed air and pressure water in a mist form. The compressed air passes through the inside of packing materials 19, 19', and is exhausted through exhaust holes 4 via vent plugs 6. The pressure water is sprayed in a mist form onto the top surface of the material 19, and percorates through the inside of the material 19', thereby forming a layer of large ventilation resistance. Following to this, by the compressed air supplied successively, the sand particles of the respective layers receive the pressure corresponding to the ventilation resistance of the layers per se and the pressure from their upper layer parts simultaneously, and since the sand particles of the lower layer receive the larger pressure, not only the material 19 on the surface of the plate 5 but also the material 19' in the intermediate and upper layers are hardened to prescribed mold hardness.</p> |
