Abstract:
Disclosed, amongst other things, is a molding apparatus and an injection molding process. The molding apparatus includes a positioner that is configured to regulate, in use, a relative position between a gate member and a nozzle of a melt distribution apparatus between a retracted position and an extended position for adjusting a volume of a nozzle melt reservoir that is definable between the gate member and the nozzle between a reduced volume and an expanded volume, respectively. The injection molding process includes regulating a relative position between a gate member and a nozzle of a melt distribution apparatus, with a positioner, into one of a retracted position and an extended position for adjusting a volume of a nozzle melt reservoir that is definable between the gate member and the nozzle between a reduced volume and an expanded volume, respectively.
Abstract:
There is provided a method ( 100, 200) of controlling an injection unit (20) for use in an injection molding system. The method ( 100, 200) includes releasing ( 1 10) a rotation control signal to a first actuator (40) to execute rotation of an injection screw (22) to extrude a shot of a molding material within a melt channel (38) therein and cause a retraction of the injection screw (22), along an axis thereof, to a resultant injection start position with accumulation of the molding material in front of the injection screw (22). In the method ( 100) the rotation control signal causes the first actuator (40) to execute rotation of the injection screw (22) through a pre-determined number of screw rotations to extrude the shot of the molding material. The method ( 100, 200) further includes releasing (220) an injection control signal to a second actuator (44) to execute advancing of the injection screw (22), along the axis thereof, to inject the shot of the molding material. In the method (200) the injection control signal transitions from a first injection control regime to a second injection control regime at a pre-determined injection transition distance from the resultant injection start position.
Abstract:
According to embodiments of the present invention, there is provided a method of operating a molding system. More specifically the method of operating a melt distribution network within a molding system, the melt distribution network including a first melt flow control device at an upstream location and a second melt flow control device at a downstream location, is provided. The method comprises actuating the first melt flow control device to its open configuration and actuating the second melt flow control device to its open configuration to connect a source of molding material with a molding cavity via the melt distribution network; actuating the second melt flow control device to its blocked configuration; actuating the first melt flow control device to its blocked configuration; said actuating the second melt flow control device and said actuating the first melt flow control device to their respective blocked configurations resulting in molding material being trapped therebetween at a trapped pressure that substantially equals to a last pressurized portion of a molding cycle pressure, said trapped pressure being maintained until a beginning of a next injection cycle.
Abstract:
A method and apparatus for extrusion of an article is provided. A die assembly can apply flows of thermoplastic material to an array of reinforcing cables to form a composite extrusion. A slider fabric can be bonded to one side of the composite extrusion. After exiting the die assembly, the slider fabric can act to support the extrudate as it passes along an elongate mandrel, which can cause the base of the slider fabric to change shape from a flat profile to the final internal profile of the article. The extruded article can then be cooled to solidify the material. The die can include cooling for the slider fabric and means for promoting penetration of the thermoplastic into reinforcing cables.