Molding die drive unit, molding unit and molding method
AssigneeIdemitsu Petrochemical Co., Ltd.
InventorsYoshiaki Saito, Tomokazu Abe, Shigeki Tamura, Tsuneo Matsui
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Abstract
A molding die drive unit capable of both of compressing and expanding (volume enlargement) molten resin in molding die and having thin shape and superior mechanical efficiency, molding unit and molding process are provided. A molding die drive unit 20 for advancing and retracting a movable die 10B relative to a cavity 10C has a large-diameter main cylinder unit 21, and a plurality of small-diameter sub cylinder unit 22 disposed around the main cylinder unit 21. After loading the molten resin, the cylinder units 21 and 22 are driven to advance and retract the movable die 10B to the cavity 10C to compress or expand the molten resin in the cavity to conduct molding process.
Claims19
An injection molding method using a molding die drive unit to compress or expand volume of a mold closed by a stationary die and a movable die adjacent a movable platen, comprising the steps of:
- applying a force to move the movable platen, the movable platen forcing the movable die to move toward the stationary die and close the mold;
- injecting molten resin into the closed mold via an opening;
- during or after injection of the molten resin, applying a force with a main cylinder unit and a plurality of sub-cylinder units to move at least a portion of one of the movable die or stationary die without movement of the movable platen;
- after forming of a molded product, applying a retracting force only with the plurality of sub-cylinder units to retract the at least a portion of one of the movable die or stationary die without opening the closed mold;
- applying a force to move the movable platen away from the stationary die to open the mold;
- and
- removing the molded product from the mold.
A molding die drive unit for changing the dimensions of a closed cavity formed by a stationary die and a movable die for receiving molten resin, the molding die drive unit being detachably attached to either the stationary die or the movable die for moving a part of or entirety of at least one of the stationary die and the movable die to be advanced and retracted relative to the closed cavity, the molding die drive unit comprising:
- a large-diameter main cylinder unit having an opening formed along a center axis;
- and
- a plurality of small-diameter sub cylinder units disposed around the main cylinder unit and spaced apart with respect to each other.
A molding die drive unit for compressing and expanding volume of a mold in a mold device formed by a stationary die and a movable die, the mold device including an advancement device for applying a force to move a movable platen, said movable platen moving said movable die to close the mold, said molding die drive unit being positioned between said movable platen and said movable die, or between said stationary die and a stationary platen, said molding die drive unit comprising:
- a main cylinder unit having a main piston member for applying a force to move at least a part of one of said movable die and said stationary die, and
- a plurality of sub-cylinder units disposed about said main cylinder unit and having sub-piston members for applying a force to move at least a part of one of said movable die and said stationary die,
- wherein said main cylinder unit and said plurality of sub-cylinder units apply force to at least a part of one of said movable die and said stationary die, separately from said advancement device.
Dependencies are inferred from the claim text.