Ultrasonic Cleaning Degassing Guide

What Is Degassing?

1. Degassing is the process of removing dissolved gases and tiny bubbles from water.

2. When ultrasonic waves are activated, the bubbles gradually rise and break apart, making the water more suitable for generating cavitation.

Why Is Degassing Required During Ultrasonic Cleaning?

1. Dissolved gases absorb ultrasonic energy

Gas in the water acts like a “sponge,” absorbing part of the ultrasonic energy and making cavitation more difficult to generate. This may cause:

• Reduced cleaning power
• Longer cleaning time
• Oil contamination on the surface becomes harder to remove

2. Tiny bubbles block ultrasonic transmission

When fresh water is heated, many tiny bubbles are often seen in the water. These bubbles may cause:

• Ultrasonic wave transmission to be blocked
• Energy dead zones
• Uneven collapse intensity

3. Unstable cavitation and energy fluctuation

Water that has not been degassed contains many uncontrolled bubbles, which may cause:

• Sudden weakening of cavitation
• Inconsistent cleaning results
• Difficulty cleaning small round holes and internal holes

4. Deep tank performance is more affected

The deeper the tank, the easier dissolved gases form vertical distribution, making the upper layer weaker in cleaning performance.
If a deep tank is not degassed, it is common to see good cleaning results at the bottom but almost no cleaning effect at the upper layer.

What Cleaning Problems Can Occur Without Degassing?

1. Poor Cleaning Performance

• Oil film does not break down, and dirt does not detach.

2. Uneven Energy Distribution Inside the Tank

• The lower layer may be stronger, while the upper layer may be weaker.

3. Longer Cleaning Time

• It may take several times longer to achieve normal cleaning results.

4. Large Bubbles Adhering to the Surface

• Large bubbles may stick to the workpiece surface.

5. Poor Cleaning of Precision Parts

• Air trapped in micro-holes may block ultrasonic waves, making internal holes difficult to clean thoroughly.

How to Determine Whether Degassing Is Complete

1. Small Bubbles Continuously Appear on the Water Surface

• This indicates that dissolved gases are still being released.

2. Large Bubbles Continue to Adhere to the Workpiece Surface

• This means that a large amount of unreleased gas still remains in the water.

3. Aluminum Foil Test Is Uneven

• When degassing is incomplete, the aluminum foil may show local fluctuations or uneven reactions.

4. Ultrasonic Sound Is Dull

• Air absorbs energy, making the ultrasonic sound less clear.

5. The Sound Becomes Clearer After Degassing

• This is the simplest way to judge whether degassing has improved.

How Long Does Degassing Take?

• Small tank (20–40 L): approximately 3–5 minutes.
• Medium tank (50–100 L): approximately 5–10 minutes.
• Large tank (100 L and above): 10–20 minutes or longer.

Degassing before ultrasonic cleaning is one of the most important steps to ensure stable cleaning performance.
Gas in the water absorbs energy, blocks cavitation, and causes uneven cleaning. Therefore, degassing makes the sound field more stable and the energy more concentrated. It can also shorten cleaning time and improve cleaning quality.
YONG JI Enterprise can design the most suitable degassing process and energy configuration according to different tank depths, frequencies, power densities, and process conditions.
This ensures that your ultrasonic cleaning system reaches the optimal cavitation state right after startup, making operation more efficient, stable, and professional.