Ultrasonic Systems for Precise Cleaning Applications
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Using Ultrasonic Cleaners to Remove Paint from Machined Parts

January 25, 2022

Removing paint from used or vintage metal parts can be difficult and time-consuming. Even accessible surfaces may be difficult to clean because high-quality paint is tightly bonded to the metal. Often it is almost impossible to remove paint from dead-end openings, deep holes, or rough seams. Traditional methods include soaking in aggressive solvents, manual scraping and scrubbing, pressure washing, and mechanical abrasion. Each of these methods involves a degree of risk for the worker and the possibility of damage to the parts.

Ultrasonic cleaning technology represents a cleaning method that is completely safe for workers and that will not damage parts if used correctly. Ultrasonic sound waves can quickly remove even the most stubborn paint coatings and the technology cleans parts completely, including surfaces in difficult-to-reach places. Vintage machined parts can then be restored with new paint on bare metal while used parts can be incorporated in rebuilt machines with confidence that they are free from contamination. Industrial ultrasonic cleaners are an ideal solution for removing old paint from parts.

How Ultrasonic Cleaning Removes Surface Contaminants from Metal Parts

In industrial ultrasonic cleaners, an ultrasonic generator produces a high-frequency signal in the kHz range. A transducer immersed in the cleaning tank solution converts the signal into sound waves that travel through the liquid. The sound wave pressure troughs create microscopic cavitation bubbles in the low-pressure region of the trough. The subsequent high-pressure peak of the wave makes the cavitation bubbles collapse, releasing an energetic pulse of liquid. When these pulses strike metal part surfaces, they dislodge any contaminants from the surface and clean down to the bare metal.

When machined parts are made from several metals, the ultrasonic frequency chosen for the cleaner becomes important. The lowest frequencies, around 26 kHz, create comparatively large bubbles and deliver a powerful cleaning action that can wear pits into the surface of soft metals such as aluminum. Higher frequencies, in the 50-100 kHz range, produce smaller bubbles and a cleaning action gentle enough for softer metals. An experienced manufacturer of industrial ultrasonic cleaners can recommend suitable frequencies for specific cleaning applications.

Improved Cleaning Performance with Heat and Detergents

While ultrasonic cleaning works well with plain water, the removal of tough contaminants such as paint can be improved by the use of solvent chemicals. Heating the solvent also improves the cleaning action. At elevated temperatures below the boiling point, the ultrasonic bubbles work quickly on the softened paint while the solvent helps to break up the paint coating and breaks the adhesive bond to the metal. With the use of heat, solvents, and detergents, industrial ultrasonic cleaners can deliver unparalleled cleaning performance in removing paint from metal surfaces.

Kaijo Ultrasonic Cleaners Are Used in Many Different Applications

Kaijo’s industry-leading experience in ultrasonic technology allows them to design and build ultrasonic cleaners for many different types of cleaning. In addition, Kaijo provides a free consultation so that customers use the right frequencies, power, transducers, heating, detergents, and/or solvents for their cleaning applications. By working closely with different industrial partners, including those refurbishing old parts and equipment, Kaijo’s experts can find the best ultrasonic cleaning solutions required for paint removal from vintage or used parts. For help on selecting the best ultrasonic cleaning system for your specific requirements, contact Kaijo for a free consultation.