| 摘要 |
PURPOSE:To prevent dislodging of a core and formation of a flash and to improve efficiency with the decreased man-hour for molding with a vacuum casting mold provided with a core by disposing the core having the side formed to the specific grade expanded upward, disposing such core in the prescribed position of a pattern plate and forming the mold including the core under the reduced pressure. CONSTITUTION:The side faces of a core 13 are formed to 0-1/10 upwardly expanded grade and such core is fitted and disposed onto the positioning projection 14 of a pattern plate 7. The pattern plate 7 is placed on a suction box 5 and a PVC sheet 2 is put on the pattern and air is sucked from the inside to adhere tightly the sheet 2 to the pattern. If the side face grade of the core is <=1/10, there is no failure of the sheet 2 by the suction. A metallic flask 8 is put on the pattern and sand grains 3 are put therein. The PVC sheet 2 is put on the flask and the air is sucked 9 to mold the sand. Even if a casting mold 10 is taken out of the plate 7, the core is not dislodged and when a molten metal is case 13, on flash is formed at the boundary of the core. Since the need for separate insertion and fastening of the core is eliminated, the man-hour is decreased and the working efficiency is improved. |
