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Method and apparatus for controlling a vent gap with active material elements

a technology of active material elements and vent gaps, which is applied in the direction of domestic applications, other domestic articles, domestic articles, etc., can solve the problems of reducing the vent gap, reducing the efficiency of the venting line, and reducing the defecting part size, etc., and achieves the effect of effective and efficien

Inactive Publication Date: 2007-10-25
HUSKY INJECTION MOLDING SYST LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This solution enables efficient control of the vent gap, reducing equipment downtime, preventing melt leakage or clogging, and allowing for lower manufacturing tolerances, resulting in improved part quality and reduced costs.

Problems solved by technology

On other occasions, the flash breaks off and remains in the vent and vent collector blocking them for the next molding cycle, and consequently the mold venting functions poorly and may result in a defective part being molded.
Another vent problem that may occur is when the vent gap is reduced or eliminated by hobbing of the mold.
Because the vent is positioned on the mold's parting line 490 the repeated opening, closing, and clamping of the mold, as it cycles, can cause the parting line surface to gradually collapse.
When the vent gap is reduced or eliminated, the resulting poor or no venting of the mold cavity during the injection process may cause defective parts to be molded.
While there is a need to vent the mold to exhaust the air displaced by the expanding preform, the risk of material entering the vent gap is much lower than it is in an injection mold in which the material is in a heated fluid condition.
A complicated, space-consuming mechanism is used at each vent location to preform this function.
If the actual time taken exceeds the preset period, an alarm is sounded, signaling an abnormality in operation.
A complex, space-consuming mechanism is mounted in the mold at the periphery of the mold cavity.

Method used

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  • Method and apparatus for controlling a vent gap with active material elements
  • Method and apparatus for controlling a vent gap with active material elements
  • Method and apparatus for controlling a vent gap with active material elements

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Experimental program
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first embodiment

2. The Structure of the First Embodiment

[0034] The first preferred embodiment of the present invention is shown in FIGS. 6 and 7, which depict a piezoceramic insert 450 mounted in a mold cavity block 460 in a vent location. The insert is electrically connected via conduit 451 to a controller 452. A melt sensor 453 is mounted in the cavity block 460 close to the insert 450 and in a position to detect the incoming melt before it reaches the insert 450. The sensor 453 is also connected via conduit 454 to controller 452.

[0035] According to an alternate embodiment of the present invention, a mold cavity may include multiple piezoceramic insert controlled vents at several locations. These inserts are all connected to the same controller, and their operation is synchronized and coordinated by the controller to adjust the individual vent gaps to vary the amount of venting available at each location. This in turn will influence to some degree how the melt front progresses in the filling of ...

second embodiment

4. The Structure of the Second Embodiment

[0044] A second preferred embodiment according to the present invention is shown in FIG. 8, which shows a mold cavity 474 with two gates 470 and 471 such that melt enters the cavity from two places. The respective melt fronts 472 and 473 eventually meet at some point near the middle of the mold cavity 474. Clearly air in the mold cavity is pushed by both melt fronts and can become trapped in the middle of the cavity absent a vent. To exhaust the air a vent 475 is provided at the location where the melt fronts 472 and 473 are expected to meet. A piezoceramic insert 476 is positioned at the vent 475 to control the vent gap. The insert is connected via conduit 477 to a controller 483 for controlling the vent gap as previously described. Vent collector channel 478 provides an enlarged passageway for the air to exit the vent. Arrow B indicates the air exhausting from the mold cavity as the melt fronts approach each other.

[0045] Sensors 479 and 48...

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Abstract

Method and apparatus for controlling a vent gap in a mold for an injection molding machine are provided, and include an active material insert configured to be regulate the degree of opening of the vent gap. The active material insert is configured to be actuated in response to signals from a controller, so as to selectively block the opening of the vent gap during the molding process. Wiring structure is coupled to the active material insert, and is configured to carry the actuation signals. Melt flow sensors may also be provided to aid in regulating the vent gap, and may be connected to the controller in order to provide real-time closed loop control over the operation of the vent gap. Preferably, the methods and apparatus are used as part of a system for controlling the flow of melt within a mold cavity.

Description

[0001] The present application is a divisional of U.S. patent application Ser. No. 10 / 830,438, filed Apr. 23, 2004, the entire contents of which are hereby incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method and apparatus in which active material elements are used in injection molding machine equipment (e.g., hot runner nozzle assemblies) in order to adjust a vent gap within a mold. “Active materials” are a family of shape altering materials such as piezoactuators, piezoceramics, electrostrictors, magnetostrictors, shape memory alloys, and the like. In the present invention, they are used to adjust the vent gap within an injection mold, thereby improving the quality of the molded article. The active material elements may also be used as sensors. [0004] 2. Related Art [0005] Active materials are characterized as transducers that can convert one form of energy to another. For example, a piezo a...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B29C45/30B29C45/00B29C45/17B29C45/34B29C45/76
CPCB29C45/34B29C45/76B29C2945/76257B29C2945/76381B29C2945/76458B29C2945/76762Y10S425/226B29C2945/76859Y10S425/812B29C2945/76006B29C2945/76525B29C2945/76732B29C45/00B29C45/17
Inventor NIEWELS, JOACHIM JOHANNES
Owner HUSKY INJECTION MOLDING SYST LTD