Sealing Tool Thermal Expansion Compensation
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Solution Overview
Problem
Existing sealing tools in thermoforming machines suffer from thermal stresses leading to undesirable deformations, increased weight, and the need for complete replacement when the sealing plate wears out, affecting sealing quality and handling.
Innovation Solution
A sealing tool design with a temperature-controlled carrier plate and sealing plate connected via detachable screws with an elastic component, allowing unhindered thermal expansion and easy adjustment of contact pressure, along with a one-point fixation for precise alignment, using materials with high thermal conductivity and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sandwich construction with carrier plate, sealing plate and compensating plate is used to avoid bimetallic effect, then thermal stress is reduced, but device complexity increases and manufacturing complexity increases
Solution Approach 1:
The sealing tool is divided into separate functional components: a carrier plate for mechanical support and a sealing plate for sealing function. This segmentation allows each component to be optimized independently and eliminates the complex sandwich construction while maintaining thermal stress resistance.
Solution Approach 2:
The compensating plate is extracted from the construction, and its function is replaced by a spring element that actively compensates for thermal expansion. This simplifies the structure by removing unnecessary components while maintaining the desired thermal compensation effect.
2Reliability
If three plates are tightly screwed together and ground to avoid thermal stress, then sealing quality is maintained, but manufacturing complexity increases and repairability decreases
Solution Approach 1:
The connection between carrier plate and sealing plate is made dynamic through the spring element, which allows for controlled movement and compensation of thermal expansion. This eliminates the need for tight grinding and complex assembly while maintaining sealing quality.
Solution Approach 2:
The spring constant and precompression force are optimized to provide the necessary contact pressure for sealing while allowing thermal expansion. This parameter optimization replaces complex manufacturing processes with simple adjustable parameters.
3Strength
If high amount of material is used in sealing tool construction, then strength and rigidity are improved, but weight increases and ease of operation decreases
Solution Approach 1:
Material is distributed locally where needed: the carrier plate provides structural strength with optimized thickness, while the sealing plate uses wear-resistant material only at the sealing surface. This local quality approach reduces overall weight while maintaining necessary strength properties.
Solution Approach 2:
Different materials are used for different functions: aluminum or aluminum alloy for the carrier plate (lightweight with sufficient strength) and wear-resistant steel for the sealing plate (strength and durability). This composite approach optimizes the strength-to-weight ratio.
4Stability of the object's composition
If sealing plate is rigidly connected to carrier plate, then structural stability is improved, but thermal expansion is restricted causing deformation
Solution Approach 1:
A spring element is introduced as an intermediary between the carrier plate and sealing plate. This spring acts as a mediator that maintains structural connection while allowing controlled movement for thermal expansion, thus resolving the contradiction between stability and thermal freedom.
Solution Approach 2:
The design explicitly accounts for thermal expansion by providing clearance and spring compensation. The spring element is precompressed to allow the sealing plate to expand thermally while maintaining contact pressure, thus accommodating thermal expansion without restriction.
5Strength
If multiple screws are used to connect sealing plate and carrier plate, then connection strength is improved, but ease of manufacture and ease of repair decrease
Solution Approach 1:
Multiple screws are reduced to a single central screw connection. This extraction of unnecessary fastening elements simplifies manufacturing and assembly while the spring element compensates for any reduced mechanical connection strength through elastic compliance.
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 design prevents thermal stresses, reduces tool weight, improves sealing quality, and simplifies the exchange of sealing plates, enabling easier handling and alignment, while maintaining uniform temperature control.
Implementation Method 1
the screw head being supported on the side of the carrier plate facing away from the films with the interposition of an elastic component
Implementation Method 2
the elastic component consists of a compression spring
Implementation Method 3
the elastic component consists of a compression spring and/or an elastomer
Implementation Method 4
the sealing plate is uniformly temperature-controlled by the defined contact with the carrier plate
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a sealing tool (1) for sealing films in a sealing station, in particular in a thermoforming machine, comprising a temperature-controlled carrier plate (2) and a sealing plate (3) arranged on the carrier plate (2) on the side facing the films. The contact force of the sealing plate (3) against the carrier plate (2) is necessarily determined by the connection of the sealing plate (3) to the carrier plate (2) within a predetermined interval.