| 摘要 |
Method, and apparatus, for producing a disc having a central aperture comprises (a) defining a cavity by a pair of mould halves, the cavity being provided with a stamper on the face of one of the mould halves; (b) injecting molten resin in the cavity to form a moulded disc; (c) punching an aperture in the moulded disc by advancing a punch into a cavity aligned with respect to a sprue bushing after the injection of molten resin is completed; and (d) withdrawing the sprue bushing while allowing the sprue bushing to apply a resisting force to the punch when the punch advances.
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