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. 15)

previous page

Conclusion

In summary, for precision parts cleaning, designer waveforms can be classified into two categories: (1) those that improve performance of the ultrasonic system and (2) those that reduce damage caused by ultrasonic waves and cavitation. In the first category, performance enhancement, are monotonic sweeping from high frequency to low frequency to purge contamination from the system, multiple frequency systems to obtain the cleaning benefits inherent at each different frequency, and higher ultrasonic frequencies to increase the cavitation density for higher percent removal rates. In the second category, damage reduction, are non-constant sweep rates to prevent exciting a delicate part into resonance, relatively flat transducer impedance characteristics to eliminate peak power shocks to delicate parts, and higher ultrasonic frequencies combined with short exposure times to lower frequencies to eliminate craters on the part surface. Figure 11 illustrates these characteristics. For rugged parts in difficult to cavitate liquids where damage is not a concern, a high power impulse type of amplitude modulation should be considered. Figure 10 illustrates this characteristic.

previous page