Method of compression molding thermoplastic material
AssigneeSumitomo (SHI) Demag Plastics Machinery GmbH
InventorUdo Besold
Life of this patent
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Abstract
In a method of compression molding thermoplastic material, a compression gap is set between half-molds of a mold having fixed and movable platens for respective attachment of the half-molds. After setting the compression gap, the mold is closed and the platens are locked by moving locking elements into respective receiving elements. Injection of plasticized material then commences into a cavity formed between the half-molds when the mold is closed. The mold then opens as a result of pressure generated by the injected plasticized material until a distance between the half-molds corresponds to the compression gap. Subsequently, the mold undergoes a closing movement through application of a clamping force, thereby compressing the plasticized material.
Claims14
A method of compression molding thermoplastic material with an injection molding machine having fixed and movable platens provided for respective attachment of half-molds and connected by tie rods, said method comprising the steps of:
- a) aligning locking elements on one of the fixed and movable platens with selected ones of receiving elements on the tie rods to thereby define a compression gap between the locking elements and the receiving elements;
- b) closing the mold,
- c) locking the platens by moving the locking elements into the selected ones of the receiving elements;
- d) starting injection of plasticized material into a cavity formed between the half-molds when the mold is closed;
- e) opening the mold as a result of pressure generated by injected plasticized material until the locking elements impact a confronting wall of the receiving elements to define a distance between the half-molds which distance corresponds to a width of the compression gap;
- and
- f) closing the mold through application of a clamping force, thereby compressing the plasticized material.
Dependencies are inferred from the claim text.