How Frequency Relates to Ultrasonic Cleaning

Time to jump back into the amazing science behind ultrasonic cleaning! As we’ve discussed in previous blogs, ultrasonic cleaning occurs in a tank of water that produces a constant series of waves alternatively expanding and compressing to create microscopic bubbles that implode, causing a non-abrasive scrubbing action superior to traditional cleaning methods. Those waves (specifically sound waves) used in ultrasonics are the key component.

Hertz, simply put, is used to measure frequency, or cycles per second. So 1 Hz would equal one cycle of a sound wave per second, 20 Hz would be 20 cycles, 100 Hz would be 100 cycles, and so on. Our ears can tell when frequency increases or decreases based on the pitch of the sound being made. The higher the frequency is, the higher the pitch. The lower the frequency is, the lower the pitch.

What is truly unique about ultrasonic cleaning, however, is its use of frequencies too high for our ears to hear. What is audible for humans is in between 20 Hz and 20 kHz (1 Kilohertz equals 1000 Hertz). In ultrasonic cleaning, the frequencies used can range from 15 kHz to 400 kHz. It is rare, though, to find parts that need frequencies at such extreme highs and lows in order to be cleaned. The typical frequency used for ultrasonic cleaning applications lands near 40 kHz.

If you are wondering which frequency would work best for your cleaning application, there is an easy way to tell what is right. Generally, the lower frequencies in ultrasonic cleaning (20-25 kHz) are best for bigger parts. You can use these frequencies for cleaning large automotive materials. The lower frequencies tend to clean more aggressively, so larger parts can handle the action.  For more sensitive and delicate cleaning applications, it is best to use higher frequencies. In the higher frequencies, the waves are able to penetrate through small holes and crevices more easily.

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