Ultrasonic Welding Pattern for Nonwoven Hygiene Articles
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Solution Overview
Problem
High-speed production machines face challenges in achieving reliable ultrasonic welding of nonwoven and film components in hygiene articles, such as incontinence diapers, due to varying weld patterns, leading to inconsistent weld strength, damage to components, and reduced device lifespan.
Innovation Solution
The ultrasonic welding pattern is designed to maintain a consistent area coverage by varying the number and distance of welds, with an index of variation in the weld area of no more than 40%, ensuring stable connections and extended device lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the joining pattern has arc-shaped areas with narrow curvature to the machine direction, then the weld pattern can follow the contour of components, but the proportion of welded area varies greatly causing unreliable welding
Solution Approach 1:
The patent applies local quality by varying the spacing between ultrasonic welding points based on the local curvature of the joining pattern. In regions with narrow curvature (high arc-shaped areas), the spacing between welding points is reduced to maintain adequate welded area proportion, while in straight sections the spacing can be larger. This local adjustment of welding point distribution ensures reliable welding throughout the entire joining pattern regardless of contour variations.
2Productivity
If high-speed production machines are used to increase productivity, then production speed increases, but the control of welding device becomes extremely problematic due to high-frequency variation
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-setting the spacing between ultrasonic welding points according to the known joining pattern geometry before production begins. The welding program is prepared in advance with optimized point distribution that accounts for all contour variations. This eliminates the need for real-time control adjustments during high-speed operation, allowing the welding device to run at full speed without control instability.
3Reliability
If the sonotrode and contour roller are brought into direct contact to prevent unwelded areas, then welding coverage is improved, but the device components suffer damage and service life is reduced
Solution Approach 1:
The patent uses the optimized distribution of ultrasonic welding points as an intermediary solution. Instead of bringing the sonotrode and contour roller into direct contact (which causes mechanical damage), the welding points are strategically positioned and spaced to ensure complete welding coverage through proper energy distribution. This intermediary approach achieves reliable welding coverage while maintaining a gap between the sonotrode and contour roller, preserving device components and extending service life.
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 approach enables reliable welding of nonwoven and film components, preventing defects and extending the service life of the ultrasonic welding device, even at high production speeds, by maintaining a controlled and consistent weld pattern.
Implementation Method 1
by welding using ultrasound or fixed by gluing
Implementation Method 2
an anvil called a sonotrode that is set into vibrations in the ultrasonic range
Data Source
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Figure 2
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AI summary
The invention relates to a disposable hygiene article (2), surgical covering item, or surgical garment, such as an incontinence diaper, incontinence pad, surgical drape, or surgical coat, comprising a composite nonwoven fabric (38) that is provided with at least one nonwoven fabric component (16) and another nonwoven fabric or foil component (10, 12). The first nonwoven fabric component (14) is attached to the other nonwoven fabric or foil component (10, 12) in at least some areas by means of a joining pattern (36) encompassing discrete ultrasonic welding points (30) in order to form the composite nonwoven fabric (38). The joining pattern (36) extends in a first direction (32) and a second direction (34) that runs perpendicular thereto, the distance in the first direction (32) being longer than the distance in the second direction (34). At least some sections of the joining pattern (36) are not rectilinear. In order to make the formation of the welded joint a secure process, the joining pattern is embodied such that the maximum index (I) of variation of the area seized by the ultrasonic welding points is 40 percent. The invention further relates to a method for producing such a hygiene article.