Abstract: Thin-walled structures of substantially uniform wall thickness are made by rotating a heated mold surface about a horizontal axis and depositing powdered thermoplastic material onto the mold surface at a rate such that the deposited powder melts on contact with the mold surface and adheres thereto. A high degree of uniformity of the wall thickness is ensured by depositing the powder onto a relatively small portion of the overall mold surface and reciprocating the powder deposition means in the direction of the axis of rotation of the mold surface to thereby uniformly cover the entire mold surface.

Abstract: Straight walled hollow containers may be molded without taper, according to the present invention. Two mold halves, when brought together define a cavity configured to the outer wall of a hollow plastic container to be injection molded, and also an opening at one end of the cavity to enclose the stem of a core defining the inner wall of the hollow plastic container. When the core is disposed in the cavity, it is centered within the latter. Thereby a space is provided between the inner walls of the mold halves and the outer wall of the core to receive plastic material injected under high pressure through a sprue, also defined by the inner walls of the mold halves. After injection, the plastic is cooled to just below the softening point of the plastic. At this point separation of the mold halves surrounding the outer portion of the core, is commenced and a force is applied to initiate withdrawal of the core from between the mold halves.

Abstract: Straight walled hollow containers may be molded without taper, according to the present invention. Two mold halves, when brought together define a cavity configured to the outer wall of a hollow plastic container to be injection molded, and also an opening at one end of the cavity to enclose the stem of a core defining the inner wall of the hollow plastic container. When the core is disposed in the cavity, it is centered within the latter. Thereby a space is provied between the inner walls of the mold halves and the outer wall of the core to receive plastic material injected under high pressure through a sprue, also defined by the inner walls of the mold halves. After injection, the plastic is cooled to just below the softening point of the plastic. At this point separation of the mold halves surrounding the outer portion of the core, is commenced and a force is applied to initiate withdrawal of the core from between the mold halves.