ABSTRACT

The various ultrasonic parameters, or degrees of freedom, available to the process engineer define what the ultimate limits are for the cleaning process. The tradi­ tional degrees of freedom available in an ultrasonic cleaning system have in­ cluded modulation of a single center frequency (sweep), variable duty cycle and amplitude control at a single frequency. All of these variables allow control of gross, or macroscopic, variables such as raw power into the liquid. The latest class of aqueous cleaning technology allows variation of the afore-mentioned pa­ rameters, but at multiple center frequencies in a single process tank. Multiple cen­ ter frequencies allow precise microscopic tuning of the energy in the individual cavitation event. Understanding and optimizing the parameters yields maximal cleaning efficiency with minimal substrate damage.