| 摘要 |
PROBLEM TO BE SOLVED: To reduce a necessary resin amount and to upgrade transferability by using a mold having a shut-off valve installed at a position froth a flow inlet side corresponding to a volume obtained by subtracting a predicted volume of a hollow part from an overall volume of a product. SOLUTION: A switching shut-off valve 4 is installed at a position of a value obtained by subtracting a predicted volume of a hollow part from an overall volume of a product, and melted resin 3 is charged in a cavity 3a via a sprue 1 and a runner 2 in the state that the valve 4 is closed. In this state, since an internal pressure is applied to the resin 3 in the cavity 3a, it is effectively transferred to a part of a fine shape. Thereafter, high pressure gas 7 is introduced from the sprue 1, and the valve 4 is opened by a cylinder 6 simultaneously or by slightly delaying. As a result, the resin 3 of the cavity 3a is urged out forward from the valve 4 to form a hollow part 7. Thus, a desired product shape 3c is obtained by a dwelling effect due to the pressure of the gas 7. |
