Sonotrode Design for Uniform In-Plane Ultrasonic Vibration

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Solution Overview

Problem

Current ultrasonic tools are limited in their ability to generate uniform in-plane vibrations along an edge or surface, which restricts their applicability in processes like ultrasonic welding and cutting, especially for larger zones, as they typically produce maximum amplitudes only at end faces or small areas due to sinusoidal amplitude distributions in simple rod structures.

Innovation Solution

The design of a sonotrode with a standing wave configuration and strategically placed slots allows for uniform in-plane vibrations along a long edge or surface, enabling efficient transmission of vibrations to a process zone, with features such as a width corresponding to an integer multiple of the wavelength and symmetrical geometry to ensure consistent amplitude distribution and robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If simple rod structures with sinusoidal amplitude distributions are used, then the structure is simple and easy to manufacture, but the amplitude is concentrated only at end faces or small areas, limiting the process zone area

Engineering Contradiction:
Improveprocess zone areaVSAvoidsonotrode structure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The sonotrode is divided into multiple segments along its length, with each segment having a specific cross-sectional area designed to control the amplitude distribution. This segmentation allows the vibration amplitude to be distributed uniformly along a long edge or surface rather than concentrated at end faces, thereby expanding the effective process zone area while maintaining structural feasibility

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different cross-sectional areas are assigned to different locations along the sonotrode to achieve local optimization of vibration amplitude distribution. The cross-sectional area varies continuously or in steps along the length to ensure uniform amplitude along the working edge, transforming the global sinusoidal distribution into a locally controlled uniform distribution that expands the usable process zone

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If the sonotrode width is increased to cover larger zones, then the process zone coverage is improved, but the amplitude uniformity deteriorates due to transverse strain effects

Engineering Contradiction:
Improveprocess zone coverageVSAvoidamplitude uniformity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The cross-sectional area of the sonotrode is varied locally along its length to compensate for transverse strain effects. By carefully designing the cross-sectional area profile, the amplitude distribution along the wide edge or surface can be maintained uniform even when the sonotrode width is increased to cover larger process zones

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The problem of amplitude uniformity across a wide sonotrode is solved by introducing variation in the third dimension (length along the sonotrode axis). Instead of trying to maintain uniform cross-section across the width, the cross-sectional area is modulated along the length to achieve uniform amplitude distribution across the wide working face

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

3Manufacturing precision

If slots are added to the sonotrode to improve vibration distribution, then the amplitude uniformity is improved, but the device complexity increases

Engineering Contradiction:
Improveamplitude uniformityVSAvoidsonotrode structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Rather than adding slots to a simple rod structure, the sonotrode is segmented into sections with varying cross-sectional areas. This segmentation approach achieves amplitude uniformity through geometric design of the continuous structure, avoiding the need for additional slots or openings while maintaining structural integrity and reducing complexity compared to slotted designs

Inventive Principle:
Principle #1Segmentation

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 enables uniform excitation of a long process zone with in-plane vibrations, enhancing the effectiveness of ultrasonic cutting and welding by allowing larger zones to be uniformly irradiated with vibrations, improving the efficiency and applicability of these processes.

Implementation Method 1

electromechanical (e.g. piezoelectric or magnetostrictive) energy converters are usually used. They serve to transform alternating electrical voltages into alternating mechanical strains

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

electromechanical (e.g. piezoelectric or magnetostrictive) energy converters are usually used. They serve to transform alternating electrical voltages into alternating mechanical strains

Methodology Applied
Scientific EffectMagnetostrictive effect: Magnetostriction

Implementation Method 3

ultrasonic tool for ultrasonic-assisted material processing... the sonotrode (4) is subject to shear bending deformations, which cause the outer sides (15) to oscillate uniformly

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 4

The dimensions of the sonotrode (4) are chosen so that the resonance frequency of the sonotrode (4) occurs at the same frequency as the resonance frequencies of the first longitudinal oscillation of booster (3) and converter (2)

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2353737B1Device and method for ultrasound material processing
Publication Date: 2014.11.26 ATHENA TECH BERATUNG
  • EP2353737B1 patent drawingFigure 1a~2c
  • EP2353737B1 patent drawingFigure 3a~5b
  • EP2353737B1 patent drawingFigure 6~7

AI summary

The object of the present invention is to provide an improved device and method for ultrasonic processing using in-plane vibrations, wherein these vibrations occur, for example, uniformly along a long edge and can be transmitted into a process zone. The invention relates to an ultrasonic processing device with at least one converter for converting electrical vibrations into mechanical vibrations and with a sonotrode for introducing the mechanical vibrations into and/or onto a material to be processed. Furthermore, the invention relates to an ultrasonic processing method, wherein a sonotrode for introducing the mechanical vibrations into and/or onto a material to be processed is excited by a converter for converting electrical vibrations into mechanical vibrations to vibrations in a specific direction. The invention thus addresses, among other things, the following:Applications include ultrasonically assisted machining processes, e.g. joining, cutting, connecting, drilling, milling, grinding, welding, etc.