Thermoformed Sheet Crimping for Added Element Attachment
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Solution Overview
Problem
Thermoformed plastic parts with added elements, such as self-gripping hooks, face issues with unreliable attachment due to material affinity problems, leading to detachment and reduced durability, and existing attachment methods are complex and costly.
Innovation Solution
The method involves crimping the added element, like a self-gripping hook, onto the thermoformed sheet by positioning it at a distance from the mold surface during thermoforming, allowing the sheet to be formed around it without adhesives or holes, ensuring a strong and long-lasting attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If added elements are attached to thermoformed parts using traditional methods (gluing or welding), then the attachment process is simple, but the attachment reliability is poor and elements detach during use
Solution Approach 1:
The added element is positioned on the mold surface before thermoforming begins, allowing the sheet to be formed around it during the molding process itself. This preliminary positioning eliminates the need for separate attachment operations while ensuring reliable integration of the element into the final part structure.
Solution Approach 2:
The attachment of the added element is merged with the thermoforming process itself. By positioning the element on the mold and forming the sheet around it during molding, the attachment operation is combined with the primary manufacturing process, eliminating the need for separate gluing or welding steps.
2Reliability
If holes are created in the sheet for attachment, then added elements can be securely fastened, but the rigidity and sealing of the part are compromised
Solution Approach 1:
The attachment method extracts the need for holes from the process. By positioning the added element on the mold surface and forming the sheet around it, the sheet material flows around the element base without requiring penetrations, thus maintaining structural integrity while achieving secure attachment through the formed recess.
3Ease of manufacture
If traditional attachment methods are used, then the process is simpler, but the manufacturing cost increases due to sophisticated control measures required
Solution Approach 1:
The attachment operation is merged with the thermoforming cycle itself. By positioning elements on the mold and forming the sheet around them during the same manufacturing cycle, separate attachment operations are eliminated, reducing overall process time and complexity while maintaining ease of manufacture.
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 approach provides a reliable and long-lasting attachment of added elements to thermoformed parts without compromising the rigidity or sealing, reducing the risk of breakage and improving the durability of the final assembly.
Implementation Method 1
The outer surface of the mold and the heated sheet are brought into contact to give the sheet its final shape
Implementation Method 2
the sheet, upon contact, is inserted between the part of the added element located away from the outer surface of the mold and the outer surface of the mold to achieve the crimping of the added element to the sheet after returning to a temperature lower than the deflection temperature under load
Data Source
Figure 1A~1C
Figure 1D~1G
Figure 2~4
AI summary
The invention relates to a workpiece having a shape produced by thermoforming from at least one sheet (3) of plastic material, such as polycarbonate, and at least one applied element (6, 8; 7, 9) that is applied to the at least one sheet and secured there, characterised in that the securing of the at least one applied element to the at least one sheet takes place at least partially by means of crimping.