Sonotrode Centering Mandrel for Ultrasonic Welding Precision
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Solution Overview
Problem
Ultrasonic welding sonotrodes for connecting PDC sensors to motor vehicle components face limitations due to a physically induced peeling effect and complex centering methods, which compromise weld strength and precision.
Innovation Solution
A sonotrode design featuring a centering mandrel integrated with the pressing element allows for precise centering of workpieces without opening the contact surface, ensuring a high-strength, closed-ring weld with reduced thermal stress and simplified centering processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate centering receptacle is used to center the adapter relative to the external component, then centering precision is improved, but the device complexity and process complexity increase
Solution Approach 1:
The centering function is merged with the sonotrode itself by integrating a centering mandrel directly into the sonotrode structure. This eliminates the need for a separate centering receptacle while maintaining centering precision. The centering mandrel is positioned coaxially within the ring-shaped contact surface, allowing the adapter to be centered during the welding process without additional centering devices.
2Ease of operation
If the ring sonotrode is opened laterally to attach the centering device externally, then centering is enabled, but the weld strength is reduced
Solution Approach 1:
The centering mandrel is integrated into the sonotrode structure rather than being attached externally through an opening. This maintains the closed-ring structure of the contact surface, preserving weld strength while enabling centering functionality. The centering mandrel is positioned within the ring structure, allowing the adapter to be centered without compromising the structural integrity of the sonotrode.
3Ease of manufacture
If two rod sonotrodes are used with weld flaps to connect the adapter, then connection is achieved, but the weld strength is severely limited by peeling effect
Solution Approach 1:
The welding process is segmented into two stages: first, the adapter is centered on the centering mandrel; second, the closed-ring contact surface welds the adapter to the external component. This segmentation allows the adapter to be precisely positioned before welding, eliminating the peeling effect associated with rod sonotrodes and weld flaps. The distributed contact pressure from the ring sonotrode creates a more robust weld with significantly reduced peeling.
4Strength
If a closed ring-shaped contact surface is used, then weld strength is improved, but centering becomes more difficult
Solution Approach 1:
The centering mandrel is integrated into the sonotrode structure, allowing the adapter to be centered during the welding process itself. This eliminates the need for separate centering operations while maintaining the closed-ring contact surface structure. The centering mandrel is positioned coaxially within the ring, enabling precise centering without compromising the structural integrity or weld strength of the closed-ring configuration.
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
The solution enables precise centering and high-strength welding of components, reducing peeling effects and thermal stress while maintaining optimal contact surface design, thus enhancing the welding process efficiency and reliability.
Implementation Method 1
The heat required for melting is generated between the components due to friction effects caused by the high-frequency vibration
Implementation Method 2
This melting is caused by a high-frequency mechanical vibration of the ultrasonic sonotrode
Data Source
Figure 1a~1b
Figure 2a~2d
Figure 3a~3b
AI summary
The invention relates to a sonotrode for an ultrasound welding system for welding workpieces (20, 30), comprising a pressure element (2) which has a contact surface, which pressure element can be applied to carry out the welding process with said contact surface on one of the workpieces (20) to be welded to each other, wherein the contact surface has an annular design. A centring pin axially projecting over the contact surface is arranged inside the annular contact surface. The invention also relates to a method for welding a connection element (20), in particular an adapter for a PDC sensor, to a component (30), in particular an exterior add-on part of a motor vehicle.