Ultrasonic Welding Tool Structured Sealing Surface for Barrier Layer Protection
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Solution Overview
Problem
Existing methods for producing sealing seams in multilayer composites often damage the barrier layer, allowing UV light to penetrate and compromising the quality of packaged products, while increasing pressure to enhance weld strength can lead to incomplete seals if product residues are present.
Innovation Solution
The method employs an ultrasonic welding tool with a structured sealing surface featuring a main and secondary processing portion, where the main seam is produced with higher pressure to ensure strong bonding and the secondary seam with lower pressure to avoid damaging the barrier layer, ensuring UV protection and complete sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pressure with which the welding tool is pressed on to the material web is increased to enhance weld strength, then the connection strength between material webs is improved, but the barrier layer is damaged allowing UV light penetration
Solution Approach 1:
The sealing surface is divided into two distinct zones: a first zone with a first surface structure that applies higher pressure for strong welding, and a second zone with a second surface structure that applies lower pressure to preserve the barrier layer. This segmentation allows different pressure levels in different regions, simultaneously achieving strong connection and UV protection.
Solution Approach 2:
Different regions of the sealing surface are given different local properties: the first zone has surface characteristics optimized for strong bonding (higher pressure application), while the second zone has surface characteristics optimized for barrier layer preservation (lower pressure application). This local differentiation resolves the contradiction between connection strength and barrier layer integrity.
2Strength
If profiled sealing surfaces are used to displace product residues and enhance welding strength, then the connection strength is improved, but the barrier layer is damaged
Solution Approach 1:
The sealing surface is segmented into functional zones: the first zone contains profiled structures for displacing product residues and creating strong welds, while the second zone has a different surface structure that provides gentler contact to preserve the barrier layer. This segmentation allows product residue management and barrier layer protection to occur simultaneously in different regions.
Solution Approach 2:
The sealing surface exhibits local quality variations where the first zone has aggressive profiled features for effective product residue displacement and strong bonding, while the second zone has milder surface characteristics that protect the barrier layer. This local differentiation resolves the conflict between effective welding and barrier layer preservation.
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 produces a strong sealing seam with a higher pressure main portion and a lower pressure secondary portion, effectively preventing UV light penetration and ensuring a complete seal without damaging the barrier layer, even when product residues are present.
Implementation Method 1
the first tool is an ultrasonic sonotrode which is excited with an ultrasonic vibration
Implementation Method 2
the two tools are moved towards each other so that the two sealing surfaces for producing the sealing seam are pressed towards each other
Data Source
AI summary
The invention relates to a welding method for material webs which each consists of a multilayer composite having a barrier layer and are connected to each other via a sealing seam. In order to provide a welding method by means of which sealing seams can be produced which, on the one hand, meet the highest demands on strength and, on the other hand, prevent light, in particular UV light, from penetrating into the product to be packaged, according to the invention, the sealing seems are produced by leading two sealing surfaces of two tools together, wherein the material webs are arranged between the sealing surfaces and the sealing seam is produced having two seams lying beside each other, a main seam and a secondary seam and, during the production of the main seam, the two sealing surfaces exert a main welding pressure on the material webs and, during the production of the secondary seam, the two sealing surfaces exert a secondary welding pressure on the material webs, wherein the secondary welding pressure is lower than the main welding pressure, at least in some sections, and, in the secondary processing step, at least one of the two sealing surfaces is structured.