Can Ultrasonic Cleaners Clean Aluminum Parts?

Ultrasonic cleaners are quite versatile. They can clean hard, rugged parts such as those made from brass or steel – even when they are heavily contaminated. Low frequencies are ideal in cleaning such parts quickly and thoroughly, but how about parts made of aluminum? Can industrial ultrasonic cleaners also be used to clean them as well?

Getting rapid and effective cleaning of aluminum parts is, in fact, more difficult. Since aluminum is a softer metal, cleaning aluminum parts requires more care and attention to prevent damage. At the same time, aluminum reacts with both acidic and base cleaners, so a neutral cleaning solution is required for an ultrasonic cleaning bath.

In general, parts with heavy contamination are cleaned with lower frequencies (between 19.5 kHz and 26 kHz) because the cleaning action of the cavitation bubbles is more intense. The cavitation bubbles also appear larger and produce high-energy blast when they collapse at sound wave peaks. This formation and collapse of bubbles generate robust cleaning action, which is effective for cleaning hard parts such as brass or steel parts.

For cleaning more fragile parts or parts with softer surfaces, a higher frequency (38 kHz and higher) must be used. The high frequency produces smaller and less energetic cavitation bubbles that will not damage aluminum parts.

If the cleaning application regularly cleans a variety of parts, including steel and aluminum parts, an ultrasonic cleaning system that can produce two or more cleaning frequencies should be used. That way, steel, and similar hard and rugged parts can be cleaned quickly at low frequencies. For aluminum parts, higher frequencies are used that produce smaller (low energy) cavitation bubbles that typically result in prolonged cleaning times.

Ultrasonic generators need to produce one or more frequencies or a range of frequencies that is right for aluminum parts.  There are other measures that can be applied for faster ultrasonic cleaning at all frequencies, but especially at high frequencies. These include using heat and/or adding cleaning agents.

Depending on the type of the contaminant to be removed, cleaning agents are usually acidic or base. Since aluminum is highly reactive to both acids and bases, neither of these cleaning agents is used in an ultrasonic bath.

Based on these restrictions, the best option for cleaning aluminum parts is to use an industrial ultrasonic cleaner at a high frequency in a heated bath with a neutral cleaning agent. The heat softens the contaminants while the neutral cleaning dissolves them. The high frequency produces small, low-energy bubbles that will clean even the most intricate aluminum parts without damaging them. This combination will produce the best cleaning results.

Read the recently published complete article “Can Ultrasonic Cleaners Clean Aluminum Parts?” to learn more. Contact Kaijo for a free consultation at 408-675-5575 or email info@kaijo-shibuya.com to discuss your ultrasonic cleaning requirements. 

How Ultrasonic Transducers Work and Are Used in Industrial Cleaning Applications

The role of a transducer in an ultrasonic cleaning system is converting the electric high-frequency signal (produced by the ultrasonic generator) into physical sound waves in the cleaning solution. Ultrasonic cleaning transducers can work at different frequencies and produce enough power to fill the cleaning tank with ultrasonic waves.

Ultrasonic cleaning transducers consist of a thick metal plate and active parts that vibrate when an electric signal is applied. When the ultrasonic waves pass from the transducer's metal plate through the cleaning solution, the wave troughs create low-pressure regions that generate cavitation bubbles. The bubbles form in the wave troughs and collapse in the ensuing wave peaks, releasing jets of energy. The collapse of the bubbles dislodges the dirt and contamination from the surface of the parts being cleaned.

In this way, the transducer turns the electric signal from the generator into physical scrubbing and cleaning action.

There are two types of transducers according to materials:

•    Piezoelectric transducer – Historically, they were constructed from delicate materials and thus had a relatively short useful lifespan when used in ultrasonic cleaning applications. The active parts consist of piezoelectric material that changes shape in tune with the vibration of the electric signal. However, recent advancements in piezoelectric materials have contributed to the re-emergence of the piezoelectric transducer. The newer materials are more rugged and can resist even the highest megahertz frequencies.

•    Magnetostrictive transducer – These consist of metal plates and coils of wire that are not easily damaged. The metal plates vibrate in tune with the high-frequency magnetic field created by the electric signal. The use of higher frequencies require shorter plates, however, there is a limit on reducing the size of the plates. As a result, magnetostrictive transducers can only be used for the lower frequencies.

There are different types of transducers can be used:

•    Immersible transducer – an independent unit with a sealed case and waterproof cable attached. As the name implies, it is usually immersed in the cleaning solution and can be placed into an ultrasonic tank to produce the required ultrasonic sound waves.

•    Bolt-on transducer – the most appropriate for new installations with a new cleaning solution tank. It can be bolted onto the sides or the bottom of the cleaning tank.

·       Permanently mounted transducer – used with turnkey ultrasonic cleaning systems that are ready to operate as a self-sufficient system.

The complete article titled “How Ultrasonic Transducers Work and Are Used in Industrial Cleaning Applications” provides more details on this topic. For a free consultation or quote contact Kaijo at 408-675-5575 or email to info@kaijo-shibuay.com.