Ultrasonic Vibration Amplitude Control via Excitation Frequency
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Solution Overview
Problem
Existing ultrasonic vibration systems face challenges in achieving high processing speeds due to the inability to quickly adjust vibration amplitudes and frequencies, leading to inefficiencies and material web guidance issues, especially at high web speeds.
Innovation Solution
A control device that converts the desired vibration amplitude into a control signal, directly connected to the frequency control input, allowing for immediate adjustment of excitation frequency to match the desired amplitude, thereby minimizing abrupt changes and optimizing system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the generator is completely switched off during non-processing intervals, then energy consumption is reduced, but the time required to switch back on and reach optimal processing amplitude is too long
Solution Approach 1:
The system dynamically adjusts the vibration amplitude by controlling the generator's output rather than completely switching it off. The amplitude is reduced to a low level during non-processing intervals, allowing the generator to remain in a ready state with minimal energy consumption while maintaining the capability to quickly resume full amplitude processing when needed.
Solution Approach 2:
The control device changes the operating parameters of the generator by adjusting the amplitude parameter. Instead of binary on/off states, the system uses continuous amplitude modulation to transition between processing and non-processing modes, enabling rapid adaptation without the delays associated with complete power cycling.
2Productivity
If the vibration amplitude is rapidly increased or decreased to achieve high processing speeds, then productivity is improved, but the control system cannot adapt quickly enough to the desired amplitude changes
Solution Approach 1:
The control device is pre-programmed with the desired amplitude profile corresponding to different processing states. When a state change is detected, the control device immediately initiates the amplitude adjustment according to the predetermined profile, eliminating the delay associated with real-time detection and calculation of the required amplitude changes.
Solution Approach 2:
The system incorporates a feedback mechanism where the actual amplitude is continuously monitored and compared with the desired amplitude. The control device adjusts the generator output based on this feedback to ensure the amplitude reaches the target value quickly and accurately, maintaining reliable control even during rapid transitions.
3Manufacturing precision
If the sonotrode is moved back and forth during non-processing intervals, then material processing is prevented, but material web guidance problems occur at high web speeds
Solution Approach 1:
The system replaces the mechanical movement of the sonotrode with electrical control of the vibration amplitude. Instead of physically moving the sonotrode away from the material web to prevent processing, the system electronically reduces the vibration amplitude to a level below the processing threshold, eliminating mechanical complexity and enabling operation at high web speeds without guidance problems.
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
Enables higher processing speeds and improved control quality by allowing rapid adaptation to changing vibration demands, reducing disturbances and ensuring consistent material processing.
Implementation Method 1
The converter typically includes piezoelectric elements that convert an alternating electrical voltage into a mechanical vibration, namely an acoustic vibration
Implementation Method 2
The converter, the sonotrode, and any amplitude transformer located between the converter and sonotrode form an ultrasonic oscillator unit. The converter, the sonotrode, and, if applicable, the amplitude transformer are all tuned to resonate at the same ultrasonic frequency
Data Source
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AI summary
The present invention relates to a system for generating acoustic ultrasonic vibration, with a generator for generating an alternating voltage (U) with a frequency f and a converter for converting the alternating voltage into acoustic ultrasonic vibration, with a control device, which captures the vibration amplitude (Aist) of the ultrasonic vibration and compares said vibration amplitude with a desired vibration amplitude (Asoll) and changes a manipulated variable with the goal of bringing the captured vibration amplitude (Aist) closer to the desired vibration amplitude (Asoll). The generator has a frequency control module with a frequency control input. The frequency control module defines, in accordance with a signal present at the frequency control input, the frequency (f) of the alternating voltage (U) to be generated. The aim of the invention is to specify a system of the aforementioned type which at least mitigates the mentioned disadvantages and allows higher processing speeds and the associated abrupt load changes. To achieve this aim, a control apparatus is provided which converts an input signal into a manipulated signal, the desired vibration amplitude (Asoll) being provided as the input signal, and the manipulated signal being connected to the frequency control input.