Written by Rachel Kohn
Here’s a note from a Tovatech customer:
In my shop selecting the correct ultrasonic frequency to employ when operating the ultrasonic cleaner depends on the items being cleaned and what is being removed. Coarse cleaning to remove heavy contaminants is generally best performed at lower frequencies such as 37 kHz because it delivers stronger cavitation action. Fine cleaning requirements use higher frequencies such as 80 kHz to create smaller, relatively gentle cavitation bubbles that more easily penetrate blind holes, threads, tight crevices and tubes.
It’s not unusual for us to get jobs that call for both coarse and fine cleaning on the same part. Sure, there are dual-frequency cleaners out there but for the most part they require manually switching frequencies from one to the other. And there are other variables we need to take into account depending on the objects being cleaned, all of which require close attention on the part of our team.
Then I heard about the Elmasonic P line of ultrasonic cleaners that can be programmed to automatically switch between 37 and 80 kHz at 30-second intervals. What a time saver in terms of monitoring and manually switching the frequencies! We’re able to take on more jobs with complex parts having large surfaces to be cleaned at 37 kHz and small holes, crevices and other tight spots at 80 kHz.
Read the rest of this entry »
Written by Bob Sandor
Most industrial and laboratory applications for an ultrasonic cleaner are fairly straightforward: select the correct ultrasonic cleaning solution, place objects to be cleaned in the ultrasonic cleaner and follow recommended procedures concerning temperature and time for the operation being performed.
Some requirements, however, call for special accessories and procedures. One of these is when parts require the use of volatile and flammable solvents to accomplish the cleaning process. In such instances care must be taken to prevent staff from inhaling vapors and to avoid an explosion. This is because cavitation action tends to vaporize the solvents and create an explosive cloud above the ultrasonic cleaner tank.
Read the rest of this entry »
Written by Bob Sandor
“Ultrasonic” is generally defined as sound above the range of hearing, which for most people is any sound over 20 kHz or 20,000 cycles per second. The lowest frequency used in a commercial ultrasonic cleaner is typically 25 kHz, which suggests that an ultrasonic cleaner operates silently.
In fact, ultrasonic cleaners do create noise as the frequencies are converted to cavitation action that impacts not only the objects being cleaned but also the cleaning tank itself. As described by OSHA “Most of the audible noise associated with ultrasonic sources, such as ultrasonic welders or ultrasonic cleaners, consists of subharmonics of the machine’s major ultrasonic frequencies.”
Read the rest of this entry »
Written by Rachel Kohn
Cavitation action in an ultrasonic cleaner tank results from the violent implosion of millions of microscopic bubbles every second. The implosion creates a temperature of 5000˚C (>9000˚F) and a jet of plasma impacting the objects being cleaned. It is this action that quickly strips away dirt and other contaminants.
Cavitation bubbles are created by ultrasonic transducers that in turn are driven by an ultrasonic generator operating at a set frequency, examples being 40 kHz at a lower level and 130 kHz at an upper level. (Several models are available with selectable dual frequencies.) Lower frequencies create more vigorous cleaning action than higher frequencies. Because of this, they are generally used for removing coarse contaminants. Higher frequencies are used for cleaning products that are more delicate or have highly polished finishes.
Read the rest of this entry »
