18) Can a large horn have two operating frequencies?

FAQ: I have two welding stacks with below impedance curve. They are working and welding, but the diagram is strange (with two resonance curves and two antiresonance frequencies). Is this a problem? Could I use the two anti-resonance points? When the generator is adjusted according to the first antiresonance point, the vibration is low. I also tested it at second antiresonance point. In that case, the vibration was high. Mr. D.S.

Curve of a wide steel ultrasonic horn with two frequencies (one is lateral). Measurement by TRZ Analyzer.

Curve of a wide steel ultrasonic horn with two frequencies (one is lateral). Measurement by TRZ® Analyzer.

If this additional resonance disappears when the sonotrode is removed, it is quite possible that a lateral mode of vibration has gotten close to the longitudinal one because of its large size. If the first frequency is the lateral one, the sonotrode will not work properly at this point. I think the second is the right one because of the larger spacing between Zr and Za. Note: I would suggest you to reduce the TRZ® software frequency range to 19-21 kHz to improve the measurement resolution.

Learn more about testing converters and acoustic stacks.
Learn more about preventive maintenance of ultrasonic acoustic stacks.