| 摘要 |
PURPOSE:To prevent the formation of defects such as pinholes due to frosting, by freezing the surface of a casting mold made of mixed sand, which has been compressed and tamped on a pattern, for forming a casting mold, then by covering at once the whole exposed surface of the frozen casting mold with a cover plate having the same shape as that of the exposed surface, and by keeping the inside of the cover plate airtight. CONSTITUTION:Mixed sand for forming a casting mold is compressed and tamped on a pattern to form a tamped casting mold, then a plate is placed on the exposed bottom surface of the tamped casting mold, and the casting mold is turned upside down. The surface of the casting mold is cooled to be frozen by the contact with coolant such as N2, CO2 etc. to <=-20 deg.C temp. The exposed surface of said frozen casting mold is covered at once with cover plate which is made of vinyl resin, PE etc. and has the same shape as that of the surface of said frozen casting mold, and is kept airtight thereby getting out of contact with the air. Hence, frosting is hardly caused between the cover plate and the frozen casting mold, consequently the frozen casting mold is stored easily and the productivity is improved. |
