Mechanical Motion and Ultrasonic Cleaning Efficiency

A cylindrical rotating basket
A cylindrical rotating basket

Ultrasonic cleaners are used in applications as diverse as jewelry shops, hospital central service supply departments, auto repair shops and PCB repair.  They are preferred over manual scrubbing with brushes and solvents because of their thorough cleaning action and ability to reach surfaces inaccessible by any other cleaning method.  Biodegradable ultrasonic cleaning solutions are also more environmentally friendly than aerosol sprays and solvents.

The contaminant-removing power of ultrasonic cavitation – the implosion of millions of minute bubbles against surfaces being cleaned – can be substantially improved by introducing two mechanical means called oscillation (also known as agitation) and rotation to the cleaning cycle.  We’ll look at these two techniques separately although in some equipment they can be combined.

What is Oscillation?

Our friends at Wikipedia define oscillation as “the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states.”  A related term, vibration, is sometimes used as a synonym.

Oscillation improves cleaning action by carrying away contaminants from the surface of products in the cleaning bath.  It increases the exposure of all surfaces to cavitation and therefore speeds the cleaning process.  It is particularly useful when cleaning complex-shaped parts.  The overall benefit is faster, more uniform and thorough cleaning.

Industrial ultrasonic cleaners available from Tovatech provide automatic and precise ± 2 cm vertical oscillation of the cleaning baskets.  As a result cleaning is accomplished 10% – 20% faster than in ultrasonic cleaners without the feature.  These cleaners are widely used for applications where small amounts of residual contamination are unacceptable.

What is Rotation?

Rotation can be described as an automatic repositioning of parts in an ultrasonic cleaning bath.  As one example parts are subjected to a tumbling action in enclosed rotating fine mesh cleaning baskets.  Generally these are small parts that are cleaned in bulk to remove machining oils and similar contaminants, and where their contacting each other during the cleaning operation does not cause damage.

Larger parts can be affixed with nylon ties to the sides of the rotating basket. As the basket rotates all surfaces are subjected to uniform ultrasonic energy, yielding improved results.  The process is particularly suited to complex-shaped parts that otherwise may require repositioning in stationary mesh baskets to achieve satisfactory cleaning on all surfaces including cracks and blind holes.

The X-tra Line mentioned above can be equipped with an optional mechanism to rotate the cleaning basket while it is oscillating. The combined action – oscillation and rotation – enhances the cleaning process by introducing a rinsing action as the rotating basket oscillates up and down in the cleaning solution.

Rotating Ultrasonic Sieve Cleaner

Tovatech also offers an ultrasonic cleaning system designed to clean fine mesh sieves by rotating them through the cleaning solution.  This is the Elma Select 300 cleaner coupled with the optional SRH 4/200 electrically powered rack that can hold four 8-inch diameter sieves on an incline.  When activated the sieves are rotated into and out of the cleaning solution allowing cavitation action to safely remove contaminants from the mesh.  This gives the 37 kHz Select 300 cleaner dual utility because it can be used for other ultrasonic cleaning requirements as well.

Contact the ultrasonic cleaning professionals at Tovatech for sound advice on selecting a cleaning system and for recommendations on increasing the efficiency of your cleaning operations.

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Read More