Method of preparing a molded article

摘要

The method includes providing a mold apparatus (1) that includes a first mold portion (11) having a contoured and perforated interior mold surface (14), and a perimeter edge (17). The mold apparatus also includes a frame (35) that surrounds at least a portion of the perimeter edge (17) of the first mold portion (11). At least one sheet retainer (148) resides on the upper surface (38) of the frame (35). Each sheet retainer (148) includes a clamp portion (151) that faces towards (or in the direction of) the perimeter edge (17) of the first mold portion (11), and which includes a reversibly closeable clamp member (154) which defines in part a clamp interior (157). Each sheet retainer (148) is independently, reversibly and laterally attached to the upper surface (38) of the frame (35), such that each clamp portion (151) is reversibly and laterally positionable relative to the perimeter edge (17) of the first mold portion (11). In the method of the present invention, each sheet retainer, with a first portion (304) of a heated thermoplastic sheet (292) retained within the clamp portion thereof, is independently, reversibly and laterally moved towards and/or away from the perimeter edge of the first mold portion. Independent reversible and lateral positioning of each sheet retainer provides control (e.g., localized control) over the thickness of the heated thermoplastic sheet that is contacted with the interior mold surface of the first mold portion during the molding process.