| 摘要 |
PROBLEM TO BE SOLVED: To manufacture products having uniform thickness, eliminate trace of a runner on the surface of the product and take out the product while being separated from the runner. SOLUTION: A tubular molded form, having no top surface, is manufactured through injection molding employing a molding tool having at least a center core 13. In this case, the center core 13 is provided with at least two or more tunnel gate units 20, 20 while the gate points of the tunnel gate units 20, 20 are arranged uniformly near the opening ends of the tubular molded form so as to be faced to parts, which become the inner wall surface of the tubular molded form. |
