Abstract: An injection molding machine for forming a multi-layer plastic article by over molding where the second layer of the article includes a portion having a different geometrical profile than the first. The injection mold machine comprises an array of one or more cores which engage arrays of one or more first cavity and arrays of one or more composite cavities. Each composite cavity is formed from the combination of a second cavity and a cavity extension which carries at least a portion of the different geometrical profile. In one embodiment, the cavity extension comprises a pair of cavity portions which are mounted adjacent the core to laterally moveable slides on a movable platen. In another embodiment, the cavity extension is a single element which is moved between a disengaged position wherein the core can be inserted into the first cavity and an engaged position wherein the core is inserted into the composite cavity.

Abstract: This invention relates to a mold design, injection molding machine and a method for forming a multi-layer plastic article by over molding where the second layer of the article includes a portion having a different geometrical profile than the first one. The novel injection mold and injection molding machine for producing over-molded articles comprises an array of one or more cores which engage arrays of one or more first cavity and arrays of one or more composite cavities. Each composite cavity is formed from the combination of a second cavity and a cavity extension which carries at least a portion of the different geometrical profile, such as a thread. In one embodiment, the cavity extension comprises a pair of cavity portions which are mounted adjacent the core to laterally moveable slides on a movable plate, that can be a stripper plate.

Abstract: A method of injection molding an over-molded article in which a cavity extension associated with a core is first moved to a disengaged position and the core is inserted into a first cavity having a defined volume in a first geometrical configuration. A first injection operation is performed into the first cavity to form a first layer of the article. The core is then removed from the first cavity with the first layer of the article on the core. The cavity extension is moved to an engagement position and the core and first layer are inserted into a second cavity. The second cavity and the cavity extension engage to form a composite cavity having a larger volume than the defined volume and define a second geometrical configuration. A second injection operation is performed into the composite cavity to over-mold the first layer to form the article. The core and cavity extension are separated from the second cavity to remove the article therefrom.