HF Welding Tool With Segmented Electrode Lamellae

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Solution Overview

Problem

Existing HF welding technologies face challenges in efficiently welding long tubes and full-profile objects without mandrels, as they often require multiple steps and may not achieve a stable, tight seal, especially when using stray fields for cable welding.

Innovation Solution

A tool with an upper and lower tool consisting of electrode lamellae with alternating polarity along and perpendicular to the axial direction, combined with a dielectric for electrical separation, enables cross field welding, allowing for a single-step welding process that produces a stable and tight seal for various insert parts, including those without mandrels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional HF welding technologies are used for welding long tubes and full-profile objects without mandrels, then the welding process becomes complex requiring multiple steps, but the welding efficiency and productivity decrease

Engineering Contradiction:
Improvewelding process simplicityVSAvoidwelding efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The electrode tools are divided into multiple electrode lamellae arranged adjacently, where each lamella can be independently polarized. This segmentation allows the creation of complex electric field patterns (main fields and stray fields) that can weld different sections of long tubes and profile objects simultaneously in a single step, eliminating the need for multiple welding steps while maintaining process simplicity.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If stray fields are used for cable welding, then the welding process can be simplified, but the seal stability and tightness deteriorate

Engineering Contradiction:
Improvewelding process simplicityVSAvoidseal stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention merges both main fields and stray fields into a single welding process. The adjacently arranged electrode lamellae are polarized such that main fields are generated between opposing lamellae while stray fields are generated at the edges. This combination allows the process to maintain simplicity (like stray field welding) while achieving stable, tight seals (like main field welding), resolving the contradiction between process simplicity and seal reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple welding steps are used to achieve stable seals, then the seal quality improves, but the manufacturing time and energy consumption increase

Engineering Contradiction:
Improveseal qualityVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention enables continuous welding action by using multiple electrode lamellae that can be simultaneously activated. The adjacently arranged lamellae create overlapping welding zones that cover the entire circumference of the insert part, allowing a single continuous welding step to produce stable seals around the entire object, eliminating the need for multiple sequential welding steps and reducing manufacturing time.

Inventive Principle:
Principle #20Continuity of useful action

4Device complexity

If conventional electrode arrangements are used, then the device structure remains simple, but the energy consumption increases

Engineering Contradiction:
Improveelectrode structure simplicityVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The invention applies local quality by polarizing different electrode lamellae differently based on their position and function. Some lamellae are polarized to generate main fields for strong welding, while adjacent lamellae are polarized to generate stray fields for edge welding. This localized polarization optimization ensures that energy is efficiently distributed across different welding zones, reducing overall energy consumption while maintaining simple electrode structure.

Inventive Principle:
Principle #3Local quality

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 the welding of almost any insert part in a single process, achieving a particularly stable and tight weld, reducing energy requirements, and allowing for a defined geometric design of the bag for medical applications.

Implementation Method 1

High-frequency welding is a welding technique in which high-frequency electrical energy is introduced into the area to be welded. The resulting mechanical vibrations cause molecular and interfacial friction, which in turn heats the materials being joined.

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 2

the electrodes can be separated from each other along the axial direction of the insert part by a dielectric material comprising a solid

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Data Source

PatentEP3414077B1Tool for hf welding, installation for producing a bag for medical purposes and method for operating such an installation
Publication Date: 2020.12.16 KIEFEL GMBH
  • EP3414077B1 patent drawingFigure 1~2
  • EP3414077B1 patent drawingFigure 3
  • EP3414077B1 patent drawingFigure 4~5

AI summary

The invention relates to various aspects of HF welding methods and HF welding devices. When welding in insert parts comprising two films extending in the same axial direction to form a bag, it is proposed that the upper tool (2) and the lower tool (3) each consist of a plurality of electrode lamellae arranged next to one another, wherein the electrode lamellae are oppositely poled alternately along the axial direction of the insert part and perpendicularly to the axial direction. This makes it possible in just one operation for insert parts of almost any desired geometry extending in the same axial direction to be welded in without a central electrode being required. With respect to tools (1) for the HF welding, it is proposed that the electrode lamellae are separated from one another along the axial direction of the insert piece by a dielectric (40), which comprises a solid body. This makes it possible for the method to be carried out with a lower energy consumption. With respect to installations for producing a bag for medical purposes, comprising a film feed, a welding station and preferably a filling station, it is proposed that the installation has a device such as that disclosed here and also a multiplicity of holding bars for holding the insert parts, wherein the holding bars are electrically separated from the HF circuit. This makes it possible for complex components to be produced efficiently.