JPS564341A - Mold molding method of screw propeller for ship - Google Patents

Abstract

PURPOSE: To make packability of flowing sand god and mold the mold without requiring any pattern retaining jig by supporting a pattern by way of extensible jigs to the top suface of a preparation mold which is formed at the circumferential edge portions to the specific shape and molding the upper mold then removing the said jigs and molding the lower mold by flowing sand.

CONSTITUTION: In order to prevent the leakage of flowing sand at the molding of the lower mold, a preparation mold 3' is beforehand molded with the contact portion 8 which becomes the supporting portion of a pattern 1 at the upper mold molding, including part (a) of the lower mold, between its outside circumferential portions (b)-(c). Next, a plurality of extensible pattern supporting jigs, for example, jacks 2' are placed by leaving a suitable spacing, on the top suface of the preparation pattern 3', and the pattern 1 is supported by these and contact porton 8. In this state, the upper mold 5' is molded on the pattern 1 surface by compaction sand and after the sand has set, the jacks 2' are contracted and removed and flowing sand is packed in the cavity between the pattern 1 and mold 3', whereby the lower mold 4' is molded. At this time, the contact portion 8 prevents the leakage of sand. Thereafter, the upper mold 5' is suspended and is stripped from the pattern and is mated and set onto the lower mold 4'.

COPYRIGHT: (C)1981,JPO&Japio