General Electric Company

Robert F Heil

John V Howard

Patrick J Bowles

Lloyd W Garrett

David S Perry

A process and apparatus for molding a plurality of articles of hardenable material such as plastic which requires each article to be maintained under heat and pressure for a cure interval. A molding press is utilized wherein there is placed a first open mold assembly having spaced die halves between supporting mold platens. At least one of the die halves has a resilient pressure pad between the die and the mold platen supporting the die half. The press is closed to maintain the mold platens in a first force applying position having a slight gap between the die halves and locking the platens in the first position. The mold assembly is removed while in its first locked position from the press and gas from the curing material is evacuated through the gap between the die halves while heating the material. The mold assembly in its first locked position is again placed in the press and the press is closed to unlock the mold assembly and apply and maintain a second molding force greater than the first molding force and sufficient to completely close the die halves to a second position for curing the material and compress the resilient pressure pad. The mold platens are locked in the second position whereby the pressure pad will apply internal forces against the dies to maintain the correct curing pressure in the event of shrinkage of the cured material. The mold assembly is removed from the press in its second locked position and the material is cured under pressure and at elevated temperatures for the correct time interval to form the article. Finally, the mold assembly is unlocked and the article is removed therefrom.

Molding process

Plastic molding apparatus including a horizontal molding press with two platens and a mold having an ejector mold half and a cover mold half that form a mold cavity, each mold half being secured to a platen with at least one platen movable horizontally relative to the other platen to and closed positions. The molding press has longitudinal rails along the top thereof parallel to the direction of relative movement of the platens. There is an elongated horizontal gantry structure supported solely by the press and movably secured to the rails with the longitudinal axis of the gantry structure being oriented normal to the rails and the gantry is movable along the rails. There are two arms, one of which depends from one end of the gantry and the other depends from the opposite end of the gantry, and these arms are movably secured to the gantry for back and forth movement along the longitudinal axis of the gantry. There is a load carrier secured to one of the arms and an unload carrier secured to the other arm, each load and unload carrier being movable with the respective arms. The two arms are movable toward each other when the mold is open to position the load carrier and unload carrier in the press simultaneously and the two arms may be moved away from each other to remove the load carrier and unload carrier from the press prior to closing the mold.

Plastic molding apparatus

An apparatus for molding a plurality of articles of hardenable material such as plastic which requires each article to be maintained under heat and pressure for a cure interval. A molding press is utilized wherein there is placed a first open mold assembly having spaced die halves between supporting mold platens. At least one of the die halves has a resilient pressure pad between the die and the mold platen supporting the die half. The press is closed to maintain the mold platens in a first force applying position having a slight gap between the die halves and locking the platens in the first position. The mold assembly is removed while in its first locked position from the press and gas from the curing material is evacuated through the gap between the die halves while heating the material. The mold assembly in its first locked position is again placed in the press and the press is closed to unlock the mold assembly and apply and maintain a second molding force greater then the first molding force and sufficient to completely close the die halves to a second position for curing the material and compress the resilient pressure pad. The mold platens are locked in the second position whereby the pressure pad will apply internal forces against the dies to maintain the correct curing pressure in the event of shrinkage of the cured material. The mold assembly is removed from the press in its second locked position and the material is cured under pressure and at elevated temperatures for the correct time interval to form the article. Finally, the mold assembly is unlocked and the article is removed therefrom.

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Louisville, KY, United States of America

Robert F Heil