Ultrasonic Welding Sonotrode Gap Control via Digital Feedback
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Solution Overview
Problem
Existing ultrasonic welding devices struggle to react quickly and flexibly to changes in operating conditions, such as varying material thickness and web speed, leading to inconsistent welding quality due to the sonotrode giving way under reaction forces, especially with uneven circumferential contours.
Innovation Solution
An ultrasonic processing device with an integrated digital controlling/regulating module within the ultrasonic generator, which processes generator data like electric voltage, current, and actual power to adjust the gap and amplitude of the sonotrode relative to the counter tool, allowing for real-time adjustments to maintain optimal power and amplitude reference values, thereby controlling the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the ultrasonic oscillating unit is fixedly positioned against a mechanical stop, then the gap between sonotrode and counter tool is stable, but the device cannot react to variations in material thickness
Solution Approach 1:
The patent applies dynamics by replacing the fixed mechanical stop with an active positioning system that can dynamically adjust the sonotrode position. The system uses sensors to detect material thickness variations and continuously adjusts the gap between sonotrode and counter tool, transforming a static configuration into a dynamic one that adapts to changing conditions while maintaining stable welding parameters.
Solution Approach 2:
The patent implements feedback control by using sensors to detect the actual gap position and material thickness, then feeding this information back to the positioning system. The controller adjusts the sonotrode position based on this feedback to maintain the optimal gap despite material variations, resolving the contradiction between stability and adaptability.
2Manufacturing precision
If the sonotrode is blocked via electromotive drive, then the position control is improved, but the reaction time to operating condition changes is delayed
Solution Approach 1:
The patent replaces the electromotive drive system with a positioning mechanism that responds more quickly to control signals. By substituting the slower mechanical-electrical conversion system with a more responsive positioning approach, the system maintains precise gap control while reducing the reaction time to operating condition changes, addressing both position precision and speed requirements.
Solution Approach 2:
The system performs preliminary actions by continuously monitoring operating conditions and pre-adjusting the sonotrode position before welding parameters deteriorate. This proactive adjustment reduces the effective reaction time by anticipating and compensating for changes before they impact welding quality.
3Reliability
If external controlling and regulating devices are used, then the welding process can be monitored, but the system complexity and response time are increased
Solution Approach 1:
The patent merges the controlling and regulating functions directly into the ultrasonic generator, eliminating the need for separate external control devices. This integration reduces system complexity by consolidating multiple functions into a single unit while maintaining comprehensive welding process monitoring and control capabilities, thus resolving the contradiction between reliability and complexity.
Solution Approach 2:
The ultrasonic generator is designed with multi-functionality, serving both as the power source and the control system. By incorporating sensing, processing, and actuation functions within the generator itself, the system achieves comprehensive monitoring and control without requiring additional external devices, reducing overall system complexity while maintaining reliability.
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 solution enables the ultrasonic processing device to react swiftly to changes in operating conditions, ensuring consistent and high-quality welding by adjusting the gap and amplitude of the sonotrode, reducing reaction times to less than 50 ms and improving the precision of data processing and welding results.
Implementation Method 1
a piezoelectric transducer (converter 22, 22') which transforms an electric oscillation into a mechanical oscillation
Implementation Method 2
an amplitude transformation part, also called booster 24, which amplifies the oscillation amplitude
Data Source
AI summary
An ultrasonic processing method and an ultrasonic processing device may include a controlling/regulating module, preferably a digital controlling/regulating module, which is integrated into a signal processing of the ultrasonic generator so that a plurality of generator data with respect to the ultrasonic generator are processible in the ultrasonic generator. At this, a power actual value Pist is compared with a power reference value Psoll of the ultrasonic generator via a gap regulator in the controlling/regulating module to specify a position reference value POSsoll of the sonotrode relative to the roll for adjustment of the power reference value Psoll of the ultrasonic generator, and/or a power actual value Pist is compared with a power reference value Psoll of the ultrasonic generator via an amplitude regulator in the controlling/regulating module to specify an amplitude reference value Asoll to the ultrasonic generator for adjustment of the power reference value Psoll.