Ultrasonic Cleaning - What Is It?
Ultrasonic cleaning is an advanced process technology that removes dirt, oil, resin, and other contaminants from solid surfaces by using high-frequency sound waves together with specially formulated cleaning solutions. Ultrasonic waves generate microscopic bubbles within the liquid; the formation and implosion of these bubbles disperse and detach contaminants from the surface. This technology delivers far more effective, faster, and more precise results in industrial surface maintenance.
Ultrasonic cleaning has become a standard solution across many industries for cleaning components with complex geometries, such as mechanical parts, plastic and rubber molds, medical instruments, and optical components.
Industrial Ultrasonic Washing Process - Detailed Steps
The steps below describe the general process followed in an ultrasonic washing application in a comprehensive manner.
Preparation Stage - Part and Tank Preparation
a) Pre-inspection and Sorting of Parts
The surfaces to be cleaned are evaluated in advance. If loose contamination, heavy oil residues, or large particles are present, manual pre-cleaning is carried out. This step increases the effectiveness of ultrasonic cleaning and improves the efficiency of subsequent stages.
b) Preparation of the Cleaning Solution
The tank is filled with a suitable cleaning solution. This may be a water-based detergent or a dedicated industrial chemical. The solutions contain surfactants that reduce surface tension, promoting bubble formation and enhancing contaminant removal efficiency.
c) Temperature Adjustment
Industrial ultrasonic cleaning is typically performed at temperatures between 50 °C and 70 °C. Higher temperatures facilitate cavitation and improve the dissolution and removal of contaminants.
Cleaning Stage - Formation of the Cavitation Effect
a) Ultrasonic Activation
The ultrasonic generator activates the transducers inside the tank, producing high-frequency sound waves, generally in the range of 20 kHz to 120 kHz.
b) Cavitation Formation
Ultrasonic waves create alternating high- and low-pressure zones within the liquid. During the low-pressure phase, millions of microscopic bubbles form; during the high-pressure phase, these bubbles implode. The implosions act on the surface and remove contaminants at a microscopic level.
c) Energy Transfer and Mechanical Effect
The energy released during bubble collapse weakens the bonds between contaminants and the surface, providing both mechanical and chemical cleaning action.
Rinsing Stage - Removal of Residues
After cleaning, the parts are transferred directly to a rinsing tank. Rinsing is a critical step to completely remove residual cleaning solution and neutralize the surface.
a) Water or Rinsing Manifold
Residual detergents and contaminants are removed using a secondary rinsing tank or flowing water jets.
b) Filtration Steps (Optional)
In large industrial systems, filtration modules keep the rinse water clean, ensuring process consistency and repeatability.
Drying Stage - Final Surface Preparation
a) Air Drying
Parts are typically dried using compressed air guns or air-blowing stations. This method prevents water stains and residue formation on the surface.
b) Thermal Drying
In some applications, low-temperature drying ovens are used to remove all remaining moisture from the material surface.
Final Inspection and Quality Assurance Stage
a) Visual and Microscopic Inspection
Cleaned parts are inspected at both macro and micro levels to confirm that no residues remain on the surface.
b) Surface Analysis
When required, surface tests such as oil analysis devices or optical microscopy are used to measure cleaning effectiveness.
c) Packaging and Delivery
After final inspection, parts are properly packaged and delivered to the production line or the end user.
Process Parameters - Settings for Effective Results
Parameter - Recommended Range / Effect
Ultrasonic Frequency: 20 kHz - 120 kHz, selected according to detail level and type of contamination
Solution Temperature: 50 °C - 70 °C, for improved cavitation
Cleaning Time: 3 min - 30 min, depending on contamination level
Rinsing Time: Typically recommended between 1 min and 10 min
Application Examples and Performance Benefits
Ultrasonic washing is widely used for mechanical parts, molds, precision optical components, medical equipment, and electronic surfaces. Thanks to cavitation, effective cleaning is achieved even on complex geometries and micro-structured surfaces.
Key Benefits
Effective contaminant removal in blind holes, recesses, and micro surfaces
High efficiency due to rapid cleaning cycles
Minimal need for rework and no surface damage
Reduced environmental impact and optimized chemical consumption
Safety and Points to Consider
During ultrasonic washing, parts and tanks may be hot. Operators should use appropriate personal protective equipment and follow manufacturer recommendations when selecting cleaning solutions. Especially in high-frequency processes, wave energy and temperature must be carefully controlled.
Conclusion - The Value of the Ultrasonic Washing Process
Ultrasonic washing provides high-quality, fast, and repeatable cleaning, particularly in industrial production and maintenance lines. When preparation, cleaning, rinsing, and drying steps are properly managed, both product quality and process continuity are significantly improved.
Advanced technology manufacturers such as FISA make it possible to carry out these steps in a systematic and efficient manner by offering machines and process support solutions that optimize ultrasonic cleaning operations.