Plastic Bag Zipper Sealing Projections Ultrasonic Welding
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Solution Overview
Problem
Plastic storage bags with zipper-type closures often leak at the intersection of the zipper profiles and side edges due to insufficient sealing capacity of heat welding alone, necessitating additional methods like ultrasonic welding to enhance sealing.
Innovation Solution
A plastic bag design featuring interlocking male and female profiles with sealing projections that are ultrasonically welded at the edges, creating a liquid-tight seal by melting the projections to bond with the bag's edges, thereby preventing leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heat welding alone is used for side sealing, then the sealing process is simple, but the sealing capacity is insufficient to seal the thicker zipper profiles
Solution Approach 1:
The patent combines heat welding with ultrasonic welding to create a composite sealing system. The heat welding provides baseline sealing while ultrasonic welding adds enhanced sealing capacity specifically at the zipper profile intersections with side edges, resolving the contradiction between process simplicity and sealing reliability
Solution Approach 2:
The ultrasonic welding is applied selectively only at the critical locations where zipper profiles intersect with side edges, rather than throughout the entire sealing perimeter. This localized approach enhances sealing capacity where most needed while maintaining overall process efficiency
2Reliability
If ultrasonic welding is added to seal zipper profiles, then the sealing capacity is improved, but the device complexity increases
Solution Approach 1:
The zipper profiles are pre-formed with specific geometric features (protrusions and recesses) during manufacturing that are designed to work with ultrasonic welding. This preliminary preparation enables the ultrasonic welding process to be more effective and simpler to implement, as the profiles are already optimized for the sealing operation
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
The described solution effectively prevents leaks at the zipper profiles' intersection with the side edges, ensuring a secure and reliable closure for liquid storage by forming a strong, melted bond between the sealing projections and the bag's edges.
Implementation Method 1
The ultrasonic welding of the zipper profiles at the bag edges involves pressing the profiles together and vibrating with ultrasonic energy. The resulting vibration friction generates heat which melts the plastic so that it welds together.
Implementation Method 2
The resulting vibration friction generates heat which melts the plastic so that it welds together.
Implementation Method 3
The resulting vibration friction generates heat which melts the plastic so that it welds together.
Data Source
AI summary
A plastic bag comprising a welded segment at its closure which comprises sealing projections and interlocking projections to form a high integrity seal at the closure edges.