Ultrasonic Sonotrode Lateral Mounting to Prevent Bending Under Welding Force
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Solution Overview
Problem
Existing ultrasonic sonotrodes with in-plane oscillation suffer from non-uniform welding forces due to bending and tilting during material processing, limiting their application to smaller welding forces and requiring specific installation spaces, as they rely on converters that increase the sonotrode length and cause unwanted vibration components.
Innovation Solution
The ultrasonic oscillating system is mounted via a holder acting on the outer surface of the sonotrode, using a material joint with flexible elements to decouple the machine stand, allowing separate regions for the holder and converter to absorb welding forces without bending the sonotrode, ensuring uniform in-plane oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sonotrode is mounted via a converter arranged symmetrically to the longitudinal central axis, then the sonotrode can be held and excited, but the sonotrode bends and tilts under welding forces, causing non-uniform sealing force and limiting application to small welding forces
Solution Approach 1:
The mounting position is moved from the longitudinal axis (one dimension) to the lateral surface (another dimension). The holder acts on the outer surface of the sonotrode at a location spaced apart from the converter, creating a separate support path that prevents bending while maintaining uniform sealing force during in-plane oscillation.
2Ease of operation
If the converter is arranged symmetrically to the longitudinal central axis, then the sonotrode can be excited with in-plane vibration, but the overall length of the sonotrode system increases, creating installation space requirements that cannot be met
Solution Approach 1:
The holder is positioned on the lateral surface of the sonotrode rather than extending the longitudinal axis. This lateral mounting approach maintains the compact longitudinal profile while providing the necessary support and excitation for in-plane vibration at the sealing surface.
3Manufacturing precision
If the holder and converter act on the sonotrode at separate regions, then welding forces can be absorbed without bending the sonotrode, but the holder structure becomes more complex
Solution Approach 1:
The support function is segmented into two independent components: the holder acting on the lateral surface and the converter acting on the end face. This segmentation allows each component to perform its specific function (support vs. excitation) without interfering with the other, preventing sonotrode bending while maintaining structural simplicity.
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 allows for reliable holding and reduced vibration damping, enabling the sonotrode to maintain consistent in-plane oscillation and absorb welding forces effectively, expanding its application range by preventing bending and tilting, and reducing the overall system length.
Implementation Method 1
the holder and the converter or the amplitude transformer to be designed separately from one another and therefore act on the sonotrode at regions which are spaced apart from one another. The application of a welding force therefore no longer leads to a bending or tilting of the sonotrode, so that the excitation vibration remains unaffected.
Implementation Method 2
The idea on which EP 2 353 737 B1 is based is to stimulate the sonotrode with a type of bending vibration, so that the core element and wing element move in opposite directions to one another. The core element is excited and due to the connection of the wing elements via the plurality of webs, this leads to a movement in the opposite direction of the sealing surface attached to the wing element.
Data Source
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AI summary
The present invention relates to an ultrasonic vibration system (1) comprising a sonotrode which has two sonotrode end faces (8, 8') and a circumferential lateral surface that connects said sonotrode end faces (8, 8') with each other. The sonotrode has an elongate core element (2) and at least one wing element (3, 4), each core element (2) and wing element (3, 4) longitudinally extending from the one sonotrode end face (8) to the other sonotrode end face (8'). The wing element (3, 4) has a sealing surface (7) which is designed to be in contact with a material for the purpose of processing same and which is connected to the core element (2) via a plurality of longitudinally interspaced connecting portions (5, 6). The ultrasonic vibration system further comprises a converter (9) which is optionally connected to the sonotrode via an amplitude transformer (11). According to the invention, the ultrasonic vibration system is connected to a machine frame via a mounting that is connected to the lateral surface.