Ultrasonic Sealing Groove Geometry for Gathered Material Threads
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Solution Overview
Problem
Existing methods for producing gathered or gatherable materials face issues such as thread damage, misplacement, and unintentional welding due to sharp edges in grooves, leading to impaired gathering properties and reduced product quality.
Innovation Solution
The device and method feature grooves with sloping, convexly curved flanks and concavely curved groove bases, eliminating sharp edges and ensuring smooth thread guidance, while the thread is fixed to the material web sections through localized welding, preventing thread movement and enhancing gathering precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If grooves with sharp edges are used to guide threads, then thread positioning is achieved, but thread damage and misplacement occur
Solution Approach 1:
The groove edges are rounded with a radius of curvature of 0.1-0.5mm instead of being sharp, creating convexly curved flanks that guide threads smoothly without causing damage. This curvature eliminates the harmful sharp edges while maintaining effective thread positioning and guidance throughout the welding process.
2Ease of operation
If grooves with sharp edges are used, then thread guidance is provided, but unintentional welding of threads occurs
Solution Approach 1:
The rounded groove edges with convex flanks provide smooth thread guidance without creating concentration points for heat and pressure that would cause unintentional welding. The curved geometry ensures threads remain properly positioned within grooves throughout the ultrasonic welding process, preventing them from contacting partial sealing surfaces where unwanted welding would occur.
3Ease of manufacture
If grooves are designed with vertical sides, then manufacturing is simplified, but thread placement precision deteriorates
Solution Approach 1:
The grooves feature convexly curved flanks with a controlled radius of 0.1-0.5mm that gradually taper toward the groove base. This curved geometry is more easily achieved through standard machining processes like grinding or polishing compared to attempting perfectly vertical sides, while simultaneously providing superior thread placement precision through the self-guiding curvature that naturally centers threads.
4Ease of manufacture
If the groove base is flat, then manufacturing is easier, but thread clamping effectiveness is reduced
Solution Approach 1:
The groove base is formed with a concave curvature that creates a cup-like receptacle for the thread. This concave shape at the groove bottom enhances thread clamping effectiveness by providing a conforming surface that distributes clamping forces more evenly and securely holds the thread in position during ultrasonic welding, while remaining manufacturable through standard finishing processes.
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 design reduces thread damage, improves thread positioning, and ensures consistent gathering by fixing the thread in place, resulting in high-quality, accurately gathered materials with improved reproducibility.
Implementation Method 1
the tool, i.e. the sonotrode of the device, is set into ultrasonic vibration
Implementation Method 2
This results in localised heating of the material located in the gap between the sealing surface and the counter-sealing surface
Implementation Method 3
The localised heating, in turn, causes the different layers of material arranged in the gap to fuse together and thus form a strong bond
Implementation Method 4
The transition between the partial sealing surfaces and the groove is designed in such a way that there are no longer any sharp edges which could make it difficult to change the threads between the grooves
Implementation Method 5
at least one of the partial sealing surfaces has, in a sectional view perpendicular to the feed direction, at least one flank sloping down towards the bottom of the groove
Data Source
AI summary
An apparatus for producing a gatherable material, wherein the material consists of at least two material web sections and one thread positioned between the material web sections, wherein the apparatus has a tool with a sealing surface and a counter-tool with a counter-sealing surface, wherein the tool and the counter-tool are arranged relative to one another such that the material web sections and the thread are guided through a gap formed by the tool and counter-tool, wherein the tool and/or the counter-tool has a groove for receiving the thread, wherein the groove is orientated in a feed direction divides the sealing or counter-sealing surface into partial sealing surfaces, and has a groove base and two side walls, wherein the side walls connect the groove base to the partial sealing surfaces, and at least one of the partial sealing surfaces has a flank which slopes down towards the groove base.