Plastic Container Rim Grooves for Burr-Free Heat Sealing
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Solution Overview
Problem
The existing heat-sealing process for thermoplastic containers, such as drinking glasses, faces challenges in achieving a perfect seal without forming sharp burrs due to the difficulty in controlling the flow of the thermoplastic material, which can lead to leaks and safety hazards.
Innovation Solution
The introduction of annular grooves on the rim of the thermoplastic container, which guide the flow of the thermoplastic material during sealing, preventing the formation of sharp burrs by containing the bulge within the grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heat-sealing process is continued to allow the bulge to spread over the collection surfaces, then a perfect seal is achieved, but the bulge overflows beyond the collection surfaces forming sharp burrs
Solution Approach 1:
The rim is segmented into distinct functional zones: the annular rib for sealing, the collection surfaces for receiving excess material, and the annular grooves recessed from the collection surfaces to contain the bulge. This segmentation allows the sealing process to proceed without burr formation by providing designated containment areas.
Solution Approach 2:
The annular grooves are pre-formed recesses that anticipate and prevent the formation of sharp burrs by providing a containment zone for the extruding thermoplastic material before it can form harmful protrusions.
2Object-generated harmful factors
If the flow process is stopped early to avoid burrs, then sharp burr formation is prevented, but protrusions remain that can cut lips or fingers
Solution Approach 1:
The annular grooves are designed to receive and contain the protrusions during the sealing process, preventing them from forming sharp cutting hazards while allowing the flow process to proceed sufficiently to eliminate protrusions.
Solution Approach 2:
The protrusions that would normally be harmful are redirected into the annular grooves, where they are contained and eventually smoothed out, converting a potential hazard into a controlled part of the sealing process.
3Manufacturing precision
If a silicone layer is placed between the heating head and lid to slow down melting, then the time interval for perfect sealing is increased, but the heating head temperature must be increased
Solution Approach 1:
The silicone layer intermediary is removed from the system. Instead, the annular grooves in the rim itself provide the necessary flow control, eliminating the need for additional materials and simplifying the heating process.
Solution Approach 2:
The rim structure itself, with its integrated annular grooves, performs the flow control function that would otherwise require a silicone layer. The grooves self-regulate the thermoplastic material flow during sealing without external intervention.
4Object-affected harmful factors
If the sealing process time is extended to eliminate protrusions, then cutting hazards are removed, but the risk of burr formation increases
Solution Approach 1:
The rim structure is divided into functional zones with annular grooves that provide a containment boundary, allowing the sealing process to extend long enough to eliminate protrusions without exceeding the point where burrs form.
Solution Approach 2:
The annular grooves add a depth dimension to the rim structure, creating a three-dimensional containment zone that allows extended flow time while preventing lateral overflow that would create burrs.
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 a more precise control of the sealing process, reducing the risk of burrs, improving manufacturing efficiency, and enabling energy savings by eliminating the need for a silicone layer, thus optimizing the heat transfer and reducing the sealing time.
Implementation Method 1
the upper center part 14 of rib 13 begins to melt under the heat and pressure exerted by the heating head 60
Implementation Method 2
heat and pressure exerted by the heating head 60
Data Source
AI summary
A method for heat sealing a lid on a thermoplastic drinking glass comprising a wall with an upper end having a rim comprising an annular rib and two collecting surfaces extending on either side of the annular rib. According to the invention, the rim also comprises first and second annular grooves extending between the annular rib and the collecting surfaces. The method comprises, during the heat sealing of the lid, a step of making all or part of the annular rib flow into the grooves.