摘要 |
A preform is supplied between a pair of molding dies, followed by heating, softening and pressing. A smallest radius of curvature in the preform is smaller than a radius of a globular member having a volume equal to that of the preform. In this fabricating method, -an abutment portion between the molding die and the preform is located at a curved surface or the center of the molding die, thereby preventing any local abutment of the preform against the molding die.
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