Apparatus for the injection molding of fluid-filled plastic bodies
AssigneeFerromatik Milacron Maschinenbau GmbH
InventorChristoph Jaroschek
Life of this patent
Estimating the term…
Abstract
A device for producing moldings of plastic material having a cavity therein filled with a fluid comprises a mold cavity, an injector for injecting flowable plastic into the mold cavity, an injector for injecting a pressurized fluid into an interior portion of the plastic, and a side cavity connected to the mold to receive flowable plastic melt expelled by the injected pressurized fluid. The side cavity may be randomly lockable and may comprise a closing stuffer which rests flush with respect to the mold cavity interior walls.
Claims16
An injection molding device having a mold cavity which maintains a constant mold volume throughout a molding process and is defined by mold cavity walls comprised of separable walls, the device comprising:
- means for injecting pressurized flowable plastic melt into the mold cavity to completely fill the mold cavity with flowable plastic melt;
- means for injecting pressurized gas into an interior of the plastic melt after both (1) the mold cavity has been completely filled with plastic melt, and (2) a part of the plastic melt has cooled along the walls of the mold cavity to form a set surface having a wall thickness;
- a first side cavity arranged outside of the mold cavity and in communication with the mold cavity to receive flowable plastic melt expelled by the injected pressurized gas;
- means for opening the communication between said first side cavity and the mold cavity to enable flowable plastic melt from said interior to be blown out of the interior and into said side cavity;
- and
- means for closing the communication between said first side cavity and the mold cavity to separate plastic melt in said side cavity from plastic melt remaining in said mold cavity, wherein said means for closing has a surface which lies flush with the mold cavity walls when said means for closing is in a closed state, said means for closing interrupting the communication such that a terminating outlet opening in the set surface is sealed with the flowable plastic melt in said interior to form a plastic body with a smooth and continuous outer surface and a wall thickness, where the outlet opening existed, which corresponds to the wall thickness of the set surface.
An injection molding device having a mold cavity which maintains a constant volume throughout a molding process and is defined by mold cavity walls comprised of separable walls, the device comprising:
- means for injecting pressurized flowable plastic melt into the mold cavity to completely fill the mold cavity with flowable plastic melt, said means for injecting said pressurized flowable plastic melt comprising a nozzle, an associated runner located between the nozzle and the mold cavity, and an injection unit,
- said injection unit comprising an interior portion and an extruder screw, said extruder screw being movable in an injection direction during injection of flowable plastic melt, and in a withdraw direction;
- means for injecting pressurized gas into an interior of the plastic melt after both (1) the mold cavity has been completely filled with plastic melt, and (2) a part of the plastic melt has cooled along the walls of the mold cavity to form a set surface having a wall thickness, said means for injecting pressurized gas being operably disposed within said interior of the plastic melt formed by the cooled portion along the walls;
- a first side cavity arranged outside of the mold cavity and in communication with the mold cavity to receive flowable plastic melt expelled by the injected pressurized gas, said first side cavity comprising an interior portion of said nozzle, an interior portion of said injection unit, and said associated runner;
- means to move said extruder in said withdraw direction during expulsion of the flowable plastic melt to enable said flowable plastic melt from said interior to be forced into said first side cavity by the injected pressurized gas.
An injection molding device having a mold cavity which maintains a constant volume throughout a molding process and is defined by separable walls, the device comprising:
- means for injecting pressurized flowable plastic melt into the mold cavity to completely fill the mold cavity with flowable plastic melt;
- means for injecting pressurized gas into an interior of the plastic melt after both (1) the mold cavity has been completely filled with plastic melt, and (2) a part of the plastic melt has cooled along the walls of the mold cavity to form a set surface having a wall thickness, said means for injecting pressurized gas operably disposed within said interior of the plastic melt formed by the cooled portion along the walls;
- a first side cavity arranged outside of the mold cavity and in communication with the mold cavity to receive flowable plastic melt expelled by the injected pressurized gas;
- means for opening the communication between said first side cavity and the mold cavity to enable flowable plastic melt from said interior to be blown out of the interior and into said first side cavity;
- means for closing the communication between said first side cavity and the mold cavity to separate plastic melt in said first side cavity from plastic melt remaining in said mold cavity, wherein said means for closing has a surface which lies flush with the mold cavity walls when said means for closing is in a closed state, said means for closing interrupting the communication such that a terminating outlet opening in the set surface is sealed with the flowable plastic melt in said interior to form a plastic body with a smooth and continuous outer surface and a wall thickness, where the outlet opening existed, which corresponds to the wall thickness of the set surface;
- and
- means for advancing and retracting said means for injecting pressurized gas, into and out of the mold cavity.
Dependencies are inferred from the claim text.