ICT
HIGHLIGHT
ULTRASONIC CLEANING: FLEXIBLE, EFFICIENT, DELICATE
Advantages of Ultrasonic Cleaning Ultrasonic cleaning is a wet chemical process based on physical principles. This combination enables the removal of both film contaminants (such as oils, greases, emulsions) and particulate contaminants such as chips and dust. Ultrasound offers the advantage that high levels of purity can be achieved within a short time, even with workpieces, parts and components with complex geometry (e.g., blind holes, undercuts). Moreover, the cleaning process is very delicate and the use of cleaning medium and chemicals is minimised.
drying. If flammable solvents are used, the ultrasound equipment must be protected against explosion. High-boiling solvents, finally, require suitable, temperature-resistant ultrasonic transducers.
Materials which can be Cleaned With ultrasound, virtually all materials can be treated. However, this process is not particularly suitable for elastic materials, soft plastics, textiles and so forth.
Cleaning Effect Components Required For the ultrasonic cleaning, a generator of ultrasonic waves, a transducer or a resonator for the transmission of waves in the liquid and a cleaning container are required. The stainless steel containers that have an inlet and outlet and can be heated are particularly suitable. Finally, in order to prevent the ultrasonic components from dry running, the cleaning container should be equipped with a level control.
Cleaning Medium
The cleaning effect is based on cavitation: the ultrasonic generator produces sound waves in a specific frequency range and the immersed transducer or resonator transfers them in the liquid. The waves create an interplay between positive and negative pressure. The vacuum steps produce tiny bubbles which implode during the overpressure steps. This releases the energy resulting from the strong currents and turbulence, almost “blowing” the dirt up.
The ultrasonic cleaning can be performed with aqueous cleaning agents or solvents. The cleaning medium is chosen depending on the material and the contamination level. The aqueous cleaning agents require a rinse to remove the washing-active substances from the surface and a subsequent
The Ultrasonic Cleaning Process In order to achieve the best cleaning results, the ultrasonic power and frequency as well as the treatment time and the cleaning medium should be adjusted according to the parts to be treated. The rule of thumb for the ultrasonic power – Watts / litres – is that its value should lie between 5 watts per litre of liquid and 20 w/l, where 5 w/l is the lower limit. The lower the frequency,
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