Insights
PCB Ultrasonic Cleaning: How Ultrasonic Cleaning Works for PCB Assemblies
What you need to know about ultrasonic cleaning of PCB assemblies in electronics manufacturing.
PCB Cleaning Process
Effective Assembly Cleaning Through Ultrasound
Ultrasonic cleaning is an important step in PCB assembly cleaning and is typically implemented as part of a broader cleaning process that includes rinsing and drying. The objective is to remove contamination from PCB assemblies and electronic components both on the surface and in hard to reach areas, including residues trapped under components.
In an ultrasonic cleaning system, transducers generate high frequency sound waves that create cavitation throughout the cleaning bath. The cavitation bubbles form, grow, and implode even near the surface of the PCB assembly. During implosion, localized pressure jets and micro turbulence help detach particles, flux residues, oils, and other contaminants from the PCB surface and from areas with limited accessibility.
Application
Which Components are Suitable for Ultrasonic Cleaning?
Ultrasonic cleaning is suitable for many types of PCB assemblies and electronic components, especially when the geometry includes hard to reach areas. In electronics manufacturing, typical examples include printed circuit boards, connectors, relays, switches, sensors, and similar assemblies. Even delicate surfaces can often be cleaned with modern ultrasonic cleaning systems when the process is properly qualified.
In general, ultrasonic cleaning can be applied to a wide range of materials including metals, plastics, glass, ceramics, and rubber. However, not all materials and not all assembled components are suitable for ultrasonic exposure. Cleaning requirements and material compatibility should always be evaluated before introducing an ultrasonic PCB cleaning process.
Why Ultrasonic Cleaning?
Ultrasonic Cleaning Offers Several Advantages:
-
Efficiency: Ultrasonic cleaning can reach hard to access areas in PCB assemblies, such as under components with low standoff heights.
-
Thoroughness: Microscopic cavitation bubbles can remove even very fine contaminants from PCB surfaces and complex geometries.
-
Time and Cost Savings: Because ultrasonic cleaning can be both efficient and thorough, it can reduce process time and labor effort in PCB assembly cleaning.
Ultrasonic Cleaning Process
What Should be Considered When Installing an Ultrasonic Process?
Ultrasonic cleaning generally is an efficient method in assembly cleaning. However, certain framework conditions must be considered, such as:
-
Definition of cleaning requirements
What type of contamination is present, which materials and component types are used, and what does this mean for material compatibility and cleaning chemistry? -
Selection of a suitable system based on requirements
Planned throughput influences system size and handling concept. Ultrasonic power, tank configuration, and equipment features should also be considered for the intended PCB assemblies. -
Setup of parameters
Ultrasonic systems operate at predefined frequencies. It must be evaluated whether the selected frequency and energy input are compatible with the components on the PCB assembly using appropriate trials and verification methods.
Our experts can help determine whether your PCB assemblies and process requirements are suitable for ultrasonic cleaning and which additional considerations are required. We support process qualification and provide options for stable implementation.
From practiceUltrasonic Cleaning among Compounds
When components are soldered onto printed circuit boards, flux residues inevitably occur. These residues can be visible around solder joints or remain hidden beneath components. The left image shows soldered and subsequently desoldered chip capacitors with flux residues beneath the stand offs. If residues are not removed, this can contribute to electrical leakage paths, short circuits, and ultimately failure of the PCB assembly. The right image shows the same areas after ultrasonic cleaning.
Flux residues were reliably removed from beneath the capacitors.
We support youDo You Want to Introduce an Ultrasonic Process?
Our process engineers are happy to support you in introducing and qualifying an ultrasonic PCB cleaning process.
Whitepaper-CollectionAdvanced and Gentle Ultrasonic Cleaning
Despite recurring myths about ultrasonic damage to circuit boards, innovations by machine suppliers and established industry practices enable safe cleaning when correctly implemented. This whitepaper explains how modern ultrasonic cleaning works and highlights the importance of frequency selection, parameter setup, and standardized verification to achieve gentle and effective cleaning of PCB assemblies.
Further InsightsThis Might also Interest You:
