Plastic Container Rim Spot Welding for Breakable Grouping
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Solution Overview
Problem
Existing methods for connecting and separating plastic containers, such as those made of polypropylene, are costly and environmentally harmful, as they require external materials like polystyrene or complex thermoforming processes, and do not easily allow for breakable connections.
Innovation Solution
A method involving thermoforming containers from a single sheet, cutting them to separate them, and forming spot welds between adjacent rims to create breakable connections, allowing for easy separation without external tools or materials, using a localized welding process that maximizes traction forces for breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If containers are thermoformed from a single sheet of plastics material with nicks or scores formed to enable separation, then manufacturing cost is reduced and containers can be grouped together, but the material must be easily breakable which limits material choices and environmental compatibility
Solution Approach 1:
The invention separates the container formation process into two stages: first thermoforming containers from a single sheet, then making precise cuts along the rims to separate them. This segmentation allows the use of any thermoformable material while enabling clean separation, resolving the contradiction between manufacturing efficiency and material versatility.
Solution Approach 2:
The invention performs preliminary cutting of the rims after thermoforming but before final separation. By pre-cutting the rims to create separation lines, the process enables easy subsequent separation without requiring the material to inherently break easily, thus expanding material choices while maintaining manufacturing efficiency.
2Ease of operation
If polystyrene is used for container formation to enable easy breaking, then containers can be easily separated after grouping, but the material is expensive and harmful to the environment due to difficulty in recycling
Solution Approach 1:
The invention extracts the separation function from the material properties and implements it through a mechanical cutting process. Instead of relying on polystyrene's inherent brittleness for easy breaking, the process makes precise cuts along the rims, allowing the use of environmentally friendly materials like polypropylene while maintaining easy separation capability.
Solution Approach 2:
The invention changes the separation mechanism from material-dependent breaking to process-dependent cutting. By controlling the cutting parameters (blade position, depth, timing) rather than relying on material brittleness, the process enables easy separation with environmentally friendly, recyclable materials.
3Ease of operation
If containers are grouped together using external elements like cases or stretch wrapping, then containers can be handled as a single unit, but the packaging is costly, creates waste, and requires demanding user handling to remove
Solution Approach 1:
The invention merges the container rims directly together through precise cutting and joining, eliminating the need for external packaging elements. The rims are cut and joined to form a unified structure that allows the containers to be handled as a single group while using minimal material, thus reducing waste while maintaining handling convenience.
Solution Approach 2:
The container rims serve multiple functions: they define the container opening, provide structural support, and enable grouping by being cut and joined together. This multi-functionality eliminates the need for separate packaging elements, reducing waste while maintaining handling convenience.
4Ease of manufacture
If containers are made by thermoforming from a single sheet with rims remaining in the initial plane, then manufacturing is simplified and cost-effective, but breaking the connection lines between rims is difficult without easy-break materials
Solution Approach 1:
The invention performs preliminary cutting of the rims after thermoforming to create defined separation lines. By pre-cutting the rims along the connection lines before final separation, the process maintains manufacturing simplicity while enabling easy subsequent separation, resolving the contradiction between these two objectives.
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
Enables the creation of grouped plastic containers that can be easily separated and reused, reducing material costs and environmental impact by using polypropylene, which is more recyclable and cost-effective than polystyrene, while maintaining the structural integrity of the containers.
Implementation Method 1
forming at least one spot weld forming a breakable connection between the facing rim segments
Implementation Method 2
thermoforming containers from the same sheet of plastics material
Data Source
AI summary
The containers are thermoformed in groups, filled, and closed. Then, the containers are separated, and placed adjacent to one another in such a manner that segments of their respective rims face each other and define between them a line of separation. On said line, at least one spot weld is formed that forms a breakable connection between the facing rim segments.