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Method for injection molding of high quality parts

  • US 6,287,488 B1
  • Filed: 02/02/1999
  • Issued: 09/11/2001
  • Est. Priority Date: 02/02/1998
  • Status: Expired due to Term
First Claim
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1. A method of injection molding thermoplastic parts, said method comprising the steps of:

  • providing a movable mold half to be mounted on a movable platen of an injection molding machine, said movable mold half including a B-half parting line plate and at least one movable mold insert surface thereon;

    providing a stationary mold half to be mounted on a stationary platen of the injection molding machine, said stationary mold half including a hydraulic cylinder plate which is configured to be fixedly attached to the stationary platen, at least one stationary mold insert fixedly attached to the hydraulic cylinder plate, and an A-half parting line plate movable with respect to said hydraulic cylinder plate by a moving device, said moving device linearly varying a distance between the A-half parting line plate and the hydraulic cylinder plate, wherein a movement of the A-half parting line plate is controlled by a control circuit;

    attaching the movable mold half to the movable platen of the injection molding machine;

    attaching the hydraulic cylinder plate of the stationary mold half to the stationary platen of the injection molding machine;

    extending the moving device of the stationary mold half so that the A-half parting line plate is extended by a predetermined distance away from the hydraulic cylinder plate;

    moving the movable platen of the injection molding machine toward the stationary mold half until the B-half parting line plate contacts the A-half parting line plate, thereby creating an expanded mold cavity between the at least one movable mold insert surface and a surface of the at least one stationary mold insert;

    injecting a predetermined percentage of an injection shot of molten material into a runner system formed by the movable mold half and stationary mold half, said predetermined percentage of the injection shot traveling through the runner system and into the expanded mold cavity, further moving the movable mold half in such a way as to decrease the predetermined distance between the A-half parting line plate and the hydraulic cylinder plate; and

    injecting a remaining percentage of the injection shot into the injection cavity, wherein upon completion of the movement of the movable mold half the injection cavity has reached a final cavity size, and the mold insert surfaces have reached a final clamp position;

    cooling the molten material in the mold cavity; and

    removing a molded part from the injection cavity.

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