The gentle, consistent hum of an ultrasonic cleaner is a familiar sound to its users. However, when this normal operating noise is replaced by loud buzzing, sharp rattling, or irregular vibrations, it can be both alarming and confusing. Is the machine broken? Is it safe to continue using? Understanding the source of these unusual sounds is the first step to resolving the issue and ensuring your cleaner operates efficiently and safely.
It's important to distinguish between the normal, high-frequency "hiss" of millions of cavitation bubbles and abnormal noises that indicate a problem. Let's explore the common causes of these strange sounds and how to address them.
First, it's crucial to recognize what normal sounds like. The core cleaning mechanism—cavitation—itself produces noise.
The "Hiss" or "Buzz": A steady, high-frequency buzzing or hissing sound is completely normal. This is the sound of countless microscopic cavitation bubbles forming and collapsing throughout the liquid. The pitch and volume can vary slightly depending on the unit's frequency (e.g., 40kHz vs 28kHz) and power setting.
Often, the source of a troubling noise isn't the machine itself, but what's inside it.
Loose Parts in the Basket: If small, loose items (like a single earring back, a screw, or a small ring) are placed directly in the basket, the powerful ultrasonic vibrations can cause them to "dance" and vibrate rapidly against the metal mesh. This creates a distinct, sharp buzzing or rattling sound.
Item Contact with the Tank Walls: If the cleaning basket is overloaded or positioned incorrectly, items inside may touch the stainless-steel walls of the tank. The vibrations are then transferred directly from the tank wall to the item, amplifying the sound into a loud, low-frequency rumbling or buzzing.
Flat Items Sticking to the Bottom: Placing a flat object (like a glass slide or a coin) directly on the tank bottom can create a suction effect. The ultrasonic waves cause it to vibrate violently against the metal, producing a very loud and concerning slapping or buzzing noise.
The liquid is not just for cleaning; it's the essential medium that transmits ultrasonic energy.
Low Water Level: Operating the cleaner with a water level below the minimum line is a primary cause of loud, abnormal operation. The transducers, which are bonded to the bottom or sides of the tank, overwork and overheat without sufficient liquid to carry the vibrations and provide cooling. This can produce a harsh, strained buzzing sound and can permanently damage the transducers.
Using Viscous Liquids: Using inappropriate liquids like thick oils or pure glycerin can severely dampen the ultrasonic waves. The transducers have to work much harder to generate cavitation, leading to a muffled, strained operating sound and poor cleaning performance.
If the above issues have been ruled out, the noise may point to an internal problem.
Loose Transducer: The transducers are permanently bonded to the tank. Over time, or due to manufacturing defect, this bond can weaken or fail. A loose transducer will vibrate against the tank at a different frequency, creating a distinct rattling or chattering noise, especially at startup. This is a serious issue that typically requires professional repair.
Failing or Overheating Electronics: The electronic components that generate the high-frequency signal (the generator) can sometimes cause a humming or buzzing from the unit's base. If the internal fan fails or the unit overheats, the sound may change or become more pronounced. A persistent, strong electrical hum could indicate a failing component.
Damaged or Resonating Basket: The cleaning basket itself can be the culprit. A loose handle or a weld that has broken can vibrate audibly. Sometimes, the basket's resonant frequency might match the ultrasonic frequency, causing it to vibrate excessively and create a loud ringing or buzzing.
Here is a step-by-step action plan to diagnose and fix the noise:
Stop and Inspect: If you hear an unusual noise, immediately pause the cleaning cycle.
Check the Load:
Ensure all items are securely placed in the basket and not loose.
Make sure no item is touching the walls or bottom of the tank.
Use the basket handle to suspend items properly.
Verify the Liquid:
Check that the liquid level is between the MIN and MAX lines.
Ensure you are using a suitable liquid (water with a appropriate cleaner is standard).
Perform an Empty Tank Test: Empty the tank, ensuring it's clean and dry. Run the machine for just 10-15 seconds. If you still hear a rattling or loud buzzing without anything inside, it strongly suggests a mechanical issue like a loose transducer.
Inspect the Basket: Run the machine with just the empty basket inside. If the noise appears, the basket may be damaged or resonating. Try using a different basket if available.
If you have gone through all the troubleshooting steps and the abnormal noise persists, it is time to contact the manufacturer or a qualified repair service. Continuing to use a malfunctioning ultrasonic cleaner can lead to complete component failure and void the warranty.
While a certain level of sound is inherent to the powerful process of ultrasonic cavitation, loud rattling, strained buzzing, or irregular vibrations are often a cry for help. In most cases, the solution is simple: redistribute the load, ensure proper liquid levels, and use the basket correctly. By understanding these common causes, you can not only silence the noise but also protect your investment and ensure your ultrasonic cleaner performs at its best for years to come.
