Abstract: A method and apparatus for thermoplastic multigated single cavity or multicavity injection molding. A plasticated melt flows along a melt distributing passageway (3), (15), (8), and enters through a plurality of gates (35) associated with and enters through a plurality of gates (35) associated with one or more mold cavity (18). Melt temperature is maintained by means of manifold heaters (26), bushing heater band (20) and, most preferably, heated probe (16). A unique melt conditioning element placed just upstream of gate (35) forces the melt to enter a plurality of inlet melt channels (51) and flow through a region of constricted cross section and/or angular change of flow direction formed by the geometric relationship of a bushing wall (13) to said element. The result is to provide, by design, various degrees of melt heating, melt filtration, and melt homogenization.

Abstract: Method and apparatus for injection compression molding of thermoplastic parts. A preferred apparatus (100) includes a platen assembly 106, a toggle clamp assembly 102, a screw injection assembly 101, a hydraulic system suitable for providing power to the toggle clamp assembly 102 and the screw injection assembly 101, and a control system 88 for operatively controlling the various hydraulic devices associated with the molding apparatus. The platen assembly 106 provides for a plurality of variable-volume mold cavities 7. In one embodiment, enlarged mold cavities 7 receive plasticized resin from the screw injection assembly 101, and compression of the injected resin is provided by the toggle clamp assembly 102. In another embodiment, the platen assembly 106 includes a floating die assembly wherein pressure created by injected resin causes die inserts 5 and support pillars 15 to slide relative to a molding plate 74. Compression in this embodiment is also preferably provided by the main toggle clamp assembly 102.

Abstract: An improved method and apparatus for high-pressure injection or compression molding of optical thermoplastic parts such as lenses or optical disks, wherein the optical surfaces of a molded part are formed by intimate contact with suitably contoured or profiled and lapped surfaces of one or more optical mold insert elements. The optical surface of such mold element is of a different composition metallurgically than is the bulk composition of the rest of the mold element, thus allowing for optimum selection for materials-of-construction parameters (such as heat transfer, load-bearing quality, and ease of fabrication) in the bulk properties of the substrate metal, without necessarily trading off against optimum optical surface characteristics (such as imperviousness to chemical oxidation or attack, resistance to scratching and abrasion, ease of generating optical surface therein).