Intelligent molding environment and method of controlling applied clamp tonnage
First Claim
1. A molding machine controller responsive, in use, to sensed data indicative of clamp closure tonnage, the machine controller arranged dynamically to adjust applied clamp pressure to balance and preferably slightly exceed an injection pressure.
3 Assignments
0 Petitions
Accused Products
Abstract
Rather than developing full closure tonnage for a substantial portion of the duration of an injection cycle, closed loop control of the clamp pressure (such as through control of hydraulic pistons) permits clamp pressure to balance exactly, but preferably slightly exceed, the instantaneous injection pressure. A first approach mimics the injection pressure profile with time, whereby applied tonnage is varied with time according to sensed pressure measurements. A second approach looks to pre-stored or historically accumulated injection pressure information and, instead of varying the tonnage, applies a constant tonnage reflecting the maximum recorded or most likely injection pressure to be experienced in the mold (as recorded stored in a look-up table associated with the particular mold configuration). A machine controller (80, 82) causes the application of applied tonnage through the platen (16, 17) and tie-bars (19, 20) of an injection molding machine (10). Pressure sensors (66-74) located either on a mold surface (50), relative to stack components (58-64) and/or relative to a force closure path of permit a microprocessor (82) to control applied clamp closure tonnage. In this way, the system consumes less power and component wear is reduced.
49 Citations
20 Claims
- 1. A molding machine controller responsive, in use, to sensed data indicative of clamp closure tonnage, the machine controller arranged dynamically to adjust applied clamp pressure to balance and preferably slightly exceed an injection pressure.
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5. A method of operating a molding machine, the method comprising:
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sensing an injection pressure;
dynamically varying an applied clamp tonnage to balance and preferably slightly exceed the sensed injection pressure.
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7. The method of operating the molding machine according to claim 6, the method further comprising:
varying the applied clamp pressure to substantially mimic an injection pressure profile.
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8. The method of operating the molding machine according to claim 6, the molding machine including a mold producing molded articles, the method further comprising:
varying clamp tonnage over time based on measured physical parameters of at least one of the mold and the molded article.
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9. The method of operating the molding machine according to claim 6, further comprising:
applying an over-pressure that ensures that the applied clamp pressure exceeds an instantaneous injection pressure by no more than 50%, preferably no more than 20%, more preferably no more than 10% and most preferably no more than about 2%.
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10. The method of operating the molding machine according to claim 6, further comprising sensing at least one of:
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hydraulic pressure;
cavity pressures;
mold movement; and
tie-bar location.
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11. An injection molding machine comprising:
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a clamp assembly adapted to support, in use, mold halves that are periodically brought together under applied clamp pressure by operation of the clamp assembly;
sensors associated with the clamp assembly, the sensors arranged to provide a sensed indication of the applied clamp tonnage and an injection pressure; and
a machine controller responsive to the sensors, the machine arranged dynamically to adjust the applied clamp pressure to balance and preferably slightly exceed an injection pressure sensed by the sensors. - View Dependent Claims (12, 13, 14)
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- 15. A combination of a molding machine controller and associated memory in which is stored injection pressure information for a molding process in a mold, the machine controller configured, in use, to access the injection pressure information to determine and control an amount of applied tonnage that is to be applied to the mold during the molding process.
Specification