Ultrasonic Cleaning Technology

Ultrasonic cleaning is primarily an aqueous tank system that uses ultrasonic energy to remove dirt, grease, oil, and baked-on carbon from parts. Contaminants such as paint, rust, glued-on gaskets, and heavy layers of baked-on carbon can also be removed by ultrasonic cleaning but require more aggressive chemistry.

Above: an ultrasonic cleaning tank with in-line waste water recovery.

Unlike some other cleaning processes, ultrasonic cleaning will not damage intricate, lightweight, or easily damaged parts.

Parts that have a tendency to tightly nest will shadow each other, reducing cleaning efficiency.

Since ultrasonic cleaning is done in a tank, it is by nature a batch process. The success of the process is very dependent on the ultrasonics, the chemistry used, part geometry, and weight of the part.

How it Works

Ultrasonic cleaning works by producing sound waves in liquids. The waves consist of both high- and low-pressure fronts. The low-pressure fronts are small enough to cause bubbles to form. The high-pressure fronts cause the bubbles to collapse. The expanding and collapsing bubbles loosen contaminants on the part surface and the chemical cleaners either dissolve or segregate the free contaminants.

As with sound waves in air, ultrasonic sound waves can be varied by both frequency (pitch) and amplitude (power). Higher frequencies will produce smaller bubbles and lower frequencies will produce larger bubbles. Larger bubbles will typically dislodge large particles and smaller bubbles small particles. Typical industrial systems are either 25 KHz or 40 KHz, which can handle the particle sizes in the range of normal automotive cleaning. Ultrasonic cleaning systems with a much higher frequency are used in the computer industry where tiny particles need to be removed.

Cleaning Anilox rollers.

Key Advantages

  • Able to clean delicate parts without damage
  • Able to clean small apertures, blind holes, and crevices
  • Able to clean sensitive parts (wiring, plastics) with
  • relatively mild chemistries
  • Does not require line-of-sight for effective cleaning

Disadvantages of Ultrasonic Cleaning

  • It is a batch process
  • Large loads are not cleaned as quickly as small loads
    due to energy absorption
  • Large heavy parts can “shadow” each other or themselves
    resulting in poor cleaning
  • Extremely thick layers of grease, and grease mixed
    with dirt, are slow to remove
  • Aggressive chemistries combined with ultrasonics can
    pinhole foil and pit some materials

AR Industries offer an extensive range of ultrasonic equipment for various applications from cleaning print cylinders, ink ducts, trays etc, to dust removal and degreasing.

An Ultrasonic tank is usually filled with a water based solution which eventually needs to be replaced. As this can be difficult and expensive to dispose, we also offer an in-line (or stand alone), PLC controlled chemical treatment system complete with filter press.

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