Packaging Recess Design for Cold Welding Prevention
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Solution Overview
Problem
Existing packaging designs, particularly thermoformed ones, face difficulties in easy gripping of the opening tab due to cold welding issues, making it hard or impossible to separate the lid from the shell part as the cutting blades wear out.
Innovation Solution
A packaging design with a recess in the shell part below the opening tab, featuring a material connection with tearing corners at a predetermined angle, allowing the opening tab to be easily grasped by pressing it into the recess, and using hard-elastic or flexible plastic materials for the shell part to facilitate separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the opening tab rests freely on the shell part to enable easy opening, then the opening operation becomes simpler, but cold welding occurs between the opening tab and shell part making gripping difficult
Solution Approach 1:
The recess is pre-formed in the shell part at the location where the opening tab will rest. This preliminary structural preparation allows the opening tab to be pressed into the recess, creating immediate mechanical separation from the shell part surface and preventing cold welding before gripping occurs.
Solution Approach 2:
The recess acts as an intermediary structure between the opening tab and the shell part surface. By providing this intermediate depression, the opening tab can be inserted and mechanically separated from direct contact with the shell part, eliminating the cold welding issue while maintaining easy gripping.
2Reliability
If the material connection is strong to prevent accidental opening, then packaging security improves, but the tearing process becomes more difficult
Solution Approach 1:
The material connection is designed with different properties in different locations: in the region of the opening tab, the material connection forms tearing corners with reduced strength to facilitate easy tearing, while in other regions the material connection maintains sufficient strength to prevent accidental opening. This local differentiation resolves the contradiction between security and ease of opening.
Data Source
Figure 1~2
Figure 3~4
AI summary
The package (1) has a shell part (2) with a receiving area (3) for consumer goods, and a cover (4) for locking the receiving area. The cover is connected with a bearing region of the shell part in a material-fit manner. An opening flap is formed in an edge region of the package using the cover. A recess (9) is formed in an edge region of the shell part as a spherical segment, where the recess is arranged below the opening-flap. The opening flap is detachably rests against the shell part. The shell part is made of plastic, and the cover is made of a plastic foil.