| 摘要 |
PURPOSE:To prevent cracking in the molding by providing an extra cavity adjacent to the gate, the said extra cavity being cut away after molding. CONSTITUTION:A ceramic material is supplied from a gate 15 and cast into the molding cavity 13 through an extra cavity 14. Since the material once passes 13 and then returns to 14, cracks are liable to develop in the extra cavity 14 due to temperature difference, but as the area where cracks develop is in the extra cavity near the gate, the molding in the molding cavity 13 remains free of any adverse deffect. |
