Ultrasonic Welding Anvil Geometry for Stable Compact Fixation

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Solution Overview

Problem

Miniaturized ultrasonic welding devices face challenges in maintaining a sufficient prestressing force between the anvil and anvil carrier, leading to unstable fixation and unwanted relative movements during the welding process, especially in compact designs.

Innovation Solution

The anvil is designed with a bearing surface featuring two sections that enclose an angle of less than 180°, allowing self-fixation on the anvil carrier, which generates restoring forces to counteract relative movements, reducing the need for additional fasteners and enabling reliable welding in small spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the ultrasonic welding device is miniaturized to reduce size, then the device becomes more compact and space-efficient, but the prestressing force between the anvil and anvil carrier becomes insufficient, leading to unstable fixation

Engineering Contradiction:
Improvedevice sizeVSAvoidfixation stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The bearing surface of the anvil is designed with a curved contour instead of a flat surface. The curvature radius is specifically chosen to match the curvature of the anvil carrier's support surface, creating a self-centering effect that maintains stable fixation even in miniaturized devices where prestressing force is limited.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The solution moves from a one-dimensional flat contact surface to a two-dimensional curved surface contact. This dimensional change allows the bearing surface to engage with the support surface over a curved area, providing radial constraint and preventing displacement in multiple directions simultaneously, thereby achieving stable fixation in compact dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the screw connection is reduced in size to accommodate miniaturization, then the device becomes more compact, but the prestressing force generated is insufficient to prevent relative movements during welding

Engineering Contradiction:
Improvescrew connection sizeVSAvoidprestressing force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The curved bearing surface distributes the prestressing force generated by the miniaturized screw connection over a curved contact area. The curvature geometry converts the axial prestressing force into radial constraint forces that prevent relative movement between the anvil and anvil carrier during ultrasonic welding.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The curved bearing surface geometry automatically generates stabilizing forces through its interaction with the curved support surface. The system uses its own geometric configuration to self-regulate and maintain stable fixation without requiring additional fastening elements or increased prestressing force from larger screws.

Inventive Principle:
Principle #25Self-service

3Reliability

If additional fasteners are added to improve fixation stability, then the anvil becomes more securely fixed, but the device complexity increases and space requirements grow

Engineering Contradiction:
Improveanvil fixationVSAvoidfastening system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The anvil's bearing surface is designed to self-fixate on the anvil carrier through its curved geometry. The curved surface automatically engages with the corresponding curved support surface, creating a self-centering and self-stabilizing mechanism that eliminates the need for additional fasteners or complex locking mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The curved bearing surface serves multiple functions simultaneously: it provides the primary load-bearing contact surface, generates self-centering forces to prevent misalignment, creates radial constraint to prevent displacement, and distributes prestressing forces evenly. This multi-functionality replaces what would otherwise require multiple separate fastening components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration ensures stable anvil fixation during ultrasonic welding, even at high energy transfer conditions, reducing relative movements and allowing for reliable ultrasonic welding in compact setups without the need for additional fasteners.

Implementation Method 1

the two sections at least partially enclose an angle (a) of less than 180° in an intermediate space (4) located between the two sections (3a, 3b)... this configuration ensures stable anvil fixation during ultrasonic welding... generating restoring forces to counteract relative movements

Methodology Applied
Scientific EffectRestoring force: Elasticity

Implementation Method 2

an ultrasonic horn and an anvil with first, second, and third plate sections... The first plate section has a first knurled area on a first side located near the ultrasonic horn

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP3925725B1Anvil, anvil support and ultrasonic welding device
Publication Date: 2023.05.17 NOVATEC GMBH INNOVATIVE TECH
  • EP3925725B1 patent drawingFigure 1
  • EP3925725B1 patent drawingFigure 2~3
  • EP3925725B1 patent drawingFigure 4~5

AI summary

The invention described herein relates to an anvil (1) for an ultrasonic welding device (100), the anvil (1) comprising: a working surface (2) formed on the anvil (1) for resting an object to be welded by means of ultrasonic vibrations; and a support surface (3) formed on the anvil (1); wherein the support surface has two sections for resting the anvil (1) on a support surface formed on an anvil carrier (10), the two sections enclosing at least partially an angle of less than 180° in a space between the two sections. The invention also relates to a corresponding anvil carrier (10) and an ultrasonic welding device (100).