Abstract:
Reinforced plastic pellets comprise thermoplastic material and reinforcement particles that are less than 15 % of a total volume of the pellets, and at least 40 % have a thickness of less than 50 nanometers. A manifold (56) has at least two spaced valve gates (64) that are independently opened and closed as directed by a controller (68) to selectively communicate the manifold to a cavity. A primary injection pressure is applied to the plasticized pellet material in the manifold (56) to fill the cavity through sequential opening and closing of the gates (64). A lower secondary injection pressure is applied to the material in the manifold to continue filling the cavity. The gates are closed to seal the manifold from the cavity when the cavity is filled. The material is held within the manifold in compression by the valves while the cavity is open to prevent expansion of the material.
Abstract:
A method for molding large parts, comprises the steps of providing a reinforced plastic melt (41) comprising at least one thermoplastic material and reinforcement particles dispersed within the at least one thermoplastic material, the reinforcement particles comprising less than 15% of a total volume of the plastic melt, at least 50% of the reinforcement particles having a thickness of less than about 20 nanomenters, and at least 99% of the reinforcement particles having a thickness of less than about 30 nanometers; communicating a tubular formation of the plastic melt to a mold assembly having a mold cavity (44) defined by mold surfaces (43), the mold surfaces (43) corresponding to a configuration of the part to be molded; applying pressurized gas to an interior of the tubular formation to expand the tubular formation into conformity with the mold surfaces (43); and solidifying the plastic melt to form the part; and removing the part from the mold assembly.