Ultrasonic Cleaners - Laserbeam31 Electronics and Computing

Ultrasonic cleaning baths are used to clean small, intricate parts from clocks, cars, jewellery, and anything else which contains a substantial number of nooks and crannies. Very large ultrasonic cleaners are often used by garages to clean items such as car brake pads and wheels which have complex mouldings. Ultimately, these devices are very good for scrubbing places which are hard to reach with a manual cloth or scrubbing brush.

Below you can see a picture of an (essentially new) ultrasonic cleaner which I found being thrown out from a research facility:

Ultrasonic baths use the following procedure to clean intricate items and rely strongly on the fundamental Physics principle that any wave carries energy; this energy can be used to create a minute scrubbing action on anything which is placed in them. They contain a metal trough which must be filled with water before the cleaning operation starts and also need electricity to operate. Ultrasonic cleaners follow this general procedure:

The water trough is filled with water. This water can be distilled if very intricate objects, which would otherwise become encrusted with limescale, are to be cleaned.
Some ultrasonic water baths heat the water with an electric element in order to further accelerate the cleaning procedure.
The object(s) to be cleaned are placed in the water and some solvent added (for example: soap, acetone, or vinegar).
The user pushes a button to trigger a number of very high-frequency (typically around 40KHz) ultrasonic oscillators under the trough which flood the water with ultrasonic waves to induce a scrubbing action on the immersed object and the solvent.
The user sets a built-in timer which automatically stops the ultrasonic oscillators after a fixed time interval.
The user may choose to run a rinse to remove any residue of solvent from the item to be cleaned by re-filling the trough with water, letting it heat up again, and running the ultrasonic cycle with no solvent.

Ultrasonic cleaners follow a variety of shapes and sizes; some may be very small (like the one pictured above) whereas some may span meters (such as those used in garages or industrial locations). Also, the ability to heat the water is non-universal. Below is the front control panel of the one shown above (note the questionable grammar!):

With regards to IT equipment, I have successfully used my ultrasonic cleaner to wash computer fans, sticks of RAM, and plastic mountings from proprietary Dell cases which are an awkward shape to scrub manually. I have not used any abrasive cleaners since these could cause metals to corrode or discolour plastics (acetone, for example, can easily do this). One must also bare in mind that a temperature greater than 65^oC must not be used when cleaning plastics since this runs the risk of deforming or melting the plastic.

One final aspect to note is that, since the cleaner reches right into the ball bearings of a computer fan, it will likely remove the oil from them meaning that the fans will need lubricating before they are run for the first time after cleaning.