Patent ID: 7682550
Filing Date: 2010-03-23
Classification: B29C

Abstract:
1. 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.