Impulse Welding Tool Profiled Sealing Surface for Medical Bags
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Solution Overview
Problem
Existing welding tools for medical packaging films struggle with accommodating shape and dimensional tolerances, leading to potential weaknesses in the weld seam and material displacement during the welding process.
Innovation Solution
A welding tool with a profiling sealing surface, featuring a plateau that protrudes from the surface to displace plasticized film material laterally, compensating for tolerances while maintaining weld seam strength, and a clamping area that remains cooler than the plasticization temperature to prevent material expulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sealing surface is increased to displace plasticized film material and compensate for tolerances, then the weld seam strength is improved, but the film thickness in the weld seam area is reduced
Solution Approach 1:
The sealing surface is profiled with a raised portion that creates localized high pressure only in specific areas during sealing. This concentrates the displacement action on the plasticized material without requiring uniform high pressure across the entire sealing surface, thereby compensating for tolerances while preserving film thickness in critical areas.
Solution Approach 2:
The raised portion on the sealing surface is designed to pre-position and displace the plasticized film material before the actual welding completes. This preliminary displacement action ensures that material is already in the correct position to fill tolerances, preventing material loss while achieving strong weld seams.
2Manufacturing precision
If a punching edge is used to separate films during welding, then dimensional accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent removes the punching edge component from the sealing surface, extracting the film separation function from the welding tool. Instead of using a cutting edge to separate films, the process relies on the natural separation of plasticized material through thermal softening and pressure-controlled displacement, simplifying the tool structure.
Solution Approach 2:
The mechanical punching/cutting action is replaced with a thermal-mechanical process. The heated sealing surface softens the film material, allowing it to be displaced and shaped by pressure rather than being mechanically cut. This substitution eliminates the need for complex punching mechanisms while achieving adequate dimensional accuracy.
3Reliability
If the sealing pressure is increased to compensate for tolerances, then the weld seam quality is improved, but material displacement to the sides increases
Solution Approach 1:
The raised portion on the sealing surface creates localized high pressure zones that direct material displacement vertically into the weld seam rather than laterally to the sides. This concentrated pressure application improves weld quality by filling tolerances while preventing unwanted material migration to adjacent areas.
Solution Approach 2:
The sealing surface profile redirects material displacement from a lateral direction to a vertical direction. The raised portion acts as a barrier that confines plasticized material within the weld seam area, channeling displacement upward into the seal rather than outward to the sides, thereby maintaining weld quality without excessive lateral material loss.
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 tool effectively compensates for manufacturing tolerances without significantly reducing the film thickness, resulting in a stronger and more stable weld seam that can handle pressurization.
Implementation Method 1
a welding tool with a profiling sealing surface, featuring a plateau that protrudes from the surface to displace plasticized film material laterally
Implementation Method 2
a clamping area that remains cooler than the plasticization temperature to prevent material expulsion
Data Source
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AI summary
The invention relates to a welding tool and a method for pulse welding films of plastic for medical packs formed as bags. The invention generally provides for the film material that has been plastified during welding, and is consequently free-flowing, to be specifically displaced by increasing the sealing surface area. The displaced film material can for instance compensate for dimensional and form tolerances. At the same time, however, the strength of the welded seam region, which adjoins the interior space of the bag, is not reduced.