Injection molding machine employing a flow path gear pump and method of use

Abstract

An innovative method and apparatus for synchronizing the flows of molten polymer or similar materials in molding systems which utilize manifolds to direct flow into one or more cavities of an injection mold. The apparatus utilizes intermeshing positive displacement, interconnected gearing systems similar to positive displacement gear pumps in hydraulic systems. These positive displacement gear mechanisms are placed in each parallel flow channel such that all flow in each channel passes through a gear mechanism. Each of the parallel pumps are connected together directly via a shaft or indirectly using hydraulic motors, stepper motors, or other motors to synchronize the parallel flows. Each flow can be different to allow the directing of flows in complex tools or when molding parts in family molds. This is accomplished either by varying the volume of each positive displacement gear mechanism by varying the thickness of the gears or by varying the speed of rotation of each of the gear mechanisms in a synchronized way. The alternative apparatus which is indirectly connected can also be utilized to allow each mold cavity to be filled as an entity by sequentially allowing a flow in any desired combination to each of the plurality of flow channels. Thus, the indirectly connected apparatus can be used in a non-synchronous manner. After a mold cavity is filled, the gear mechanisms can be utilized as melt pumps to continue packing or holding plastic in the mold cavity. By reversing the pump mechanisms, precise decompression of the flow channels to eliminate gate stringing and other adverse effects can be accomplished.

Dependencies are inferred from the claim text.