Thermoforming Apparatus Deformation Sensor and Counterweight
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Solution Overview
Problem
Thermoforming machines face challenges in handling large loads without increasing frame and linkage size, and in mitigating elastic and plastic deformation during the forming process, especially when dealing with newer plastic sheet materials and complex geometries that require higher forming pressures.
Innovation Solution
A thermoforming machine with a differential load source and deformation sensing system that adjusts the platen shut height to counteract deformation, using a pair of coacting platens, a load-bearing structural member, and deformation sensors to detect and compensate for load path deformation during the forming operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large arrays of articles are provided on die plates on a platen, then the surface area subject to pneumatic pressure increases, but very large loads are generated on the kinematic drive linkages and frame
Solution Approach 1:
A differential load source applies a counteracting force to the platen, creating a balanced force system that offsets the large loads generated during forming operations with large arrays of articles, thereby reducing the load on the frame and drive linkages
2Manufacturing precision
If greater forming pressures and loads are applied to newer plastic sheet materials and complex geometries, then manufacturing precision improves, but elastic deformation of thermoforming machine components increases
Solution Approach 1:
The differential load source applies a counteracting force that balances the high forming loads, preventing elastic deformation of frame and component members, thereby maintaining machine geometry stability while enabling high precision forming of complex geometries
Solution Approach 2:
Deformation sensors detect separation between dies caused by frame deformation and provide feedback to the control system, which adjusts the differential load source to compensate for the deformation in real-time, maintaining manufacturing precision
3Strength
If the size and strength of traditional frames and linkages are increased to handle larger loads, then load bearing capacity improves, but device complexity and size increase
Solution Approach 1:
Instead of increasing frame and linkage size to handle larger loads, a differential load source applies counteracting forces to balance the loads during operation, maintaining load bearing capacity while keeping the frame and linkage structure compact and simple
Solution Approach 2:
The system transitions from a static, over-engineered frame structure to a dynamic system where the differential load source actively adjusts counteracting forces based on real-time deformation sensor feedback, optimizing load management without increasing structural size
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for precise control and mitigation of deformation, enabling the formation of articles under high loads without the need for larger frames, ensuring accurate die plate engagement and maintaining machine geometry despite temperature changes, thus improving the efficiency and accuracy of the thermoforming process.
Implementation Method 1
The deformation sensor is configured to span a first location and a second location on the structural member to detect deformation indicative of separation between the dies resulting from deformation
Data Source
AI summary
A thermoforming apparatus is provided having a pair of coacting platens, a load bearing structural member, a force applicator, and a deformation sensor. The pair of coacting platens and respective dies are configured to mate on opposed surfaces of a heated sheet of thermoformable material to form articles. The load bearing structural member is configured to carry the coacting platens and the dies in complementary closed relationship about the sheet during an article forming operation. The force applicator is carried by the structural member and configured to impart a forming load between the pair of opposed dies and platens and across the structural member during a forming operation. The deformation sensor is configured to span a first location and a second location on the structural member to detect deformation indicative of separation between the dies resulting from deformation. A method is also provided.