| 摘要 |
PURPOSE:To prevent deformation in burning, by arranging a cylindrical core on alumina balls, and burning the core. CONSTITUTION:Almina balls 2 are placed on a burning case 3. A cylindrical core 1, which has an outer diameter of 20 mm, an inner diameter of 13 mm and a height of 18 mm, is arranged on the balls and burned. As a result, the circularity of the outer diameter of the cylindrical core can be made 0.15 mm or less. Thus the deformation of the cylindrical core in burning can be prevented. |
