METHOD FOR INCREASING FEEDING EFFECT

PURPOSE:To improve a feeding effect with the intensification of pressurizing force and to permit easy parting of a casting by disposing a riser head having an opened air chamber on the bottom surface to the upper part of the riser chamber of a casting mold and sinking the same into the molten metal in the riser thereby retarding the solidification of the riser. CONSTITUTION:The riser head 1 having the opened 3a air chamber 3 on the bottom surface is disposed in the upper part of the riser part 4 of the casting mold. The head 1 is sunk by descending of a push plate 5 and ejector pins 6 into the molten metal 4b raised and packed into the riser part 4. The pressurizing force is intensified by the expulsion of the molten metal 4b and the thermal expansion and heat insulating characteristic of the air in the air chamber 3 by which the solidification of the riser is retarded and the ascent and flocculation of impurities are improved. The parting of the casting is made easy by rising a cope 20 after the solidification of the molten metal.