Overmolding Plastic Collar on Thin-Walled Container Rim
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Solution Overview
Problem
Thin-walled disposable containers, such as plastic cups and bowls, face issues with dimensional stability, temperature sensitivity, and inadequate sealing due to their material properties, making it difficult to attach a stable and airtight plastic collar using conventional methods.
Innovation Solution
A method involving an injection mold with a movable insert that receives plastic webs at the edge, allowing for overmolding of a collar from all sides, providing stability and enabling precise formation of a stable rim through sequential plastic injections, with the option to use different plastics for enhanced strength and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If thin-walled disposable containers are used to reduce cost and improve ecology, then material consumption and cost are reduced, but dimensional stability and temperature resistance deteriorate
Solution Approach 1:
The invention uses composite construction by combining the thin-walled container (made from deep-drawn film material) with an overmolded plastic collar. The collar is integrated directly onto the container rim through injection molding, creating a composite structure that provides the dimensional stability and strength needed for handling and sealing, while the thin-walled body maintains low material consumption and cost.
2Stability of the object's composition
If the container wall is thickened or beaded to improve dimensional stability, then dimensional stability improves, but manufacturing complexity increases and deep-drawn film containers cannot be produced
Solution Approach 1:
The invention segments the container structure into two functional parts: the thin-walled deep-drawn body (produced by film forming) and the reinforced collar (produced by injection molding). This segmentation allows each part to be manufactured using the most suitable process for its function, avoiding the need to complicate the deep-drawing process while still achieving dimensional stability.
Solution Approach 2:
The invention merges the container and collar into a single integrated component through overmolding. The collar is injection-molded directly onto the container rim in one operation, creating a permanent bond. This combining eliminates the need for separate manufacturing and assembly steps, simplifying the overall manufacturing process while providing structural reinforcement.
3Ease of manufacture
If conventional attachment methods are used to attach a plastic collar, then manufacturing simplicity is maintained, but sealing performance and holding strength deteriorate
Solution Approach 1:
The invention merges the attachment process with the collar formation process through integrated injection molding. The collar is not separately attached but is molded directly onto the container rim, creating a monolithic structure. This eliminates potential failure points from separate attachment methods (mechanical joining, welding, or gluing) while ensuring excellent sealing performance and holding strength.
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 method enhances the stability and structural integrity of thin-walled containers by creating a robust rim and achieving an airtight seal, addressing the challenges of handling and temperature sensitivity, while allowing for various plastic combinations for optimal performance.
Implementation Method 1
these still plastic webs now already have sufficient load-bearing capacity to hold the extremely light insert in position
Implementation Method 2
achieve an airtight seal
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A method and an injection mold for carrying out the method are proposed. The method allows a plastic collar (22) to be injection-molded onto an insert (20) with a circumferential rim (21). For this purpose, the insert (20) is placed in a receiving cavity (7) of an injection mold (1). In a first step, radially outwardly directed plastic ribs are formed, and then means (5) of the injection mold (1) are lowered, the lower part of the collar is completely formed, and finally, in a third injection step, an upper plastic layer of the collar is formed on top of the rim (21).