Use of ultrasonic plants for cleaning and degreasing

The use of ultrasonic cleaning systems requires a few unusual features which demand clear and unambiguous concepts.

Over the years, numerous companies involved in the ultrasonic cleaning system sector have emerged; and as one business closes, at least three are opened by former employees. Some limit themselves to the application of generators and transducers bought on the open market, others build shameless copies of existing devices, always several steps behind from the moment they start.

Everyone tells the story they choose, however it suits them at the time, and the customer is left confused by all the contradicting advice they receive, one contradiction after another.

This is a good point to stop and clarify a few fundamental concepts, so the customer can focus on selecting the system which best meets their requirements, without having to subject themselves to unwanted advice.

The technique – Step by Step

  • Ultrasonic power

    The definition of ultrasound power enjoys a rich vocabulary which is combined with numerous terms: peak, pulsing, sweep mode and so forth. This is determined by Ohms Law P=VxI, therefore establishing the power of an ultrasonic generator could not be easier.

  • Multifrequency

    Frequency variation avoids the formation of points with more or less power (nodes) in order to even out the effect of ultrasound across the surface of the part to be treated.

  • Transducers (magnetostrictive or piezoelectric)

    Currently, 90% of industries in the sector use piezoelectric transducers which are more efficient and produce less noise compared to massive magnetostrictive transducers.
    Especially since the ceramics industry began to produce special PZT elements using metal oxides which were highly suitable for the purpose (lead zirconate-titanate and barium).

  • The piezoelectric effect

    The piezoelectric effect is produced in an object if this physical phenomenon is present: an elongation corresponds to a variation in the voltage on the two opposing faces. For example, the voltage measured on the poles increases in proportion to the elongation.

  • Cavitation

    When turbulence is created in a liquid, bubbles (cavities) form which contain high pressure vapour which immediately implodes, freeing the energy in the form of vapour pressure.

  • Pulsing function (Pulse Mode)

    Pulse mode is a particular measure which consists of the succession of periods of power which are 50-80% superior to the normal power, followed by equal periods of zero power.

  • Variable frequency (Sweep Mode)

    The generator is equipped with a special program which is set in the workshop and checked at the site of the final test. In this way, the effective base frequency and the range to set can be determined with precision.

  • IGBT Modules

    IGBT modules are the alternative to power MOSFETs in the manufacture of high frequency generators. In fact, their use has many advantages, including the reduced size of the circuit board, the number of components and the size of the package.

  • Degasification (degassing)

    The elimination of gases dissolved in cleaning liquids is completely indispensable for good sonic wave propagation in the cleaning liquid. In fact, air is present in the form of numerous gas bubbles.

  • Noise Levels

    All ultrasonic cleaning systems are very noisy and annoying, as the noise they produce is quite particular with a whistle that is clearly distinguishable, even at a distance in an environment which is itself noisy.