Article Contents

1. Introduction
2. FM: Sweep and Dual Sweep
3. Ultrasonic Power Into a Tank
4. FM: Upsweep
5. Multiple Frequencies (1)
6. Multiple Frequencies (2)
7. Cavitation
8. Transducer Impedence (1)
9. Transducer Impedence (2)
10. Transducer Impedence (3)
11. Universal Transducer
12. Applying the Technology (1)
13. Applying the Technology (2)
14. Applying the Technology (3)
15. Conclusion

Designer Waveforms: Ultrasonic Technologies to Improve Cleaning and Eliminate Damage
(p. 6)

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Multiple Frequencies (continued)

Although more time is needed before a clear case can be made for which class of multiple frequency equipment will win in the commercial world, initial indications are that it is the third class of equipment.

There are many performance advantages inherent in this third class of multiple frequency equipment. A typical part being cleaned has many types and sizes of contamination; each different frequency works best on a different subset of this contamination. Therefore, improved cleanliness is obtained when a full range of different frequencies is used to clean the parts. The order in which the different frequencies are presented to the parts has been shown to have a unique cleaning effect. This implies the best cleaning results when many different permutations of the cleaning frequencies are presented to the parts. The useful effects of lower frequencies can be employed without the damage from cavitation by limiting the time they are input into the system to fractions of a second. Various chemistries, processes and parts can be accommodated in the same tank because of the wide range of programmed frequencies available in a multiple frequency system of the class III type.

Although the parameters that effect the energy in each cavitation implosion and the cavitation density are only loosely related to designer waveforms, a quick review of these topics is appropriate.

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