| 摘要 |
<p>PURPOSE: To generate hardly cavities, and the surface roughening in a product and to improve the manufacturing technology for a mold by forming an intermediate room with an expanded path crosssection on the midway of a sprue. CONSTITUTION: A conically recessed port 30 is formed on one end of a mold 3 formed in a mold ring 4. A sprue 31 constituted of an intermediate room 311 and a straight part 312 following this is continued to the outlet part 301 of this port 30 and the intermediate room 311 is formed by expanding the diameter of the sprue 31. In addition, the intermediate room 311 is formed into a semi-spherical shape being projected downward and the top wall 315 of the intermediate room 311 is made to be horizontal. In addition, a mold part 32 coinciding with the shape of an repaired article of a crown of tooth such as a crown is formed on the apex part of the straight part 312 following the intermediate room 311. As air admixed in a molten liq. is removed thereby in the intermediate room 311, air is hardly mixed in the molten liq. flowing into a casting part 32 to generate hardly cavities or surface roughening in an repaired article of a crown as a product.</p> |
