METHOD FOR MOLDING CYLINDRICAL MOLDING AND MOLD FOR INJECTION MOLDING USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a method for molding a cylindrical molding capable of eliminating a warp or a deformation with an entire accuracy even in the molding like having an undercut part like a groove on an inner peripheral surface, facilitating handling of a mold including maintenance without needing secondary working of the undercut part and being used for molding the molding having a small header size and the mold for injection molding used for the method. SOLUTION: The method for molding the cylindrical molding comprises the steps of rotating an eccentric core orbital revolution core die having a protruding stripe or a groove on the peripheral surface so that a maximum outer diameter is substantially same as or slightly smaller than a minimum inner diameter of the core die in a drawing direction around a central axis of a cavity in a state in which the core die is eccentrically deviated from the central axis of the cavity in the cavity, and molding the molding while compressing a charging resin charged in the cavity in a direction of the fixed mold.