MEDICAL ELECTRONICS
Why cleaning medical PCBAs is getting harder
By Elizabeth Norwood, senior chemist, MicroCare M
edical electronics are becoming smaller, more complex and more densely populated. As a result, cleaning Printed Circuit Board Assemblies (PCBAs) is no longer a straightforward process. What was once a routine step in assembly is now a critical part of ensuring reliability and compliance. Modern medical assemblies often combine packages and tight standoff heights. These cleaning processes to access. Residues from trapped beneath components or within narrow gaps, where they are not easily removed.
At the same time, device expectations have increased. PCBAs used in diagnostic, monitoring and implantable systems must operate reliably over extended periods, often in demanding environments. Even tiny amounts of contamination can have a
Material selection is adding another layer of complexity. Designers are now using electrical and mechanical requirements. These materials do not always respond predictably during cleaning.
Some exhibit low surface energy, making moisture or be affected by temperature. In of the board may respond differently to the same cleaning process, making it harder to achieve a consistent outcome.
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Why aqueous cleaning struggles Aqueous cleaning remains widely used, but its limitations are becoming more apparent with modern medical PCBAs. The process depends on water and detergents reaching all contaminated areas, followed by effective rinsing and drying.
is not always achieved. Low standoff components and tightly spaced features remove residues. Even when cleaning appears successful, contamination can remain in hidden areas.
Drying is often the bigger issue. Water can be retained beneath components or within is limited. In medical applications, trapped moisture increases the risk of corrosion, failures.
There are also material concerns. Exposure to water and elevated drying temperatures can affect certain substrates, leading to dimensional changes or surface degradation. As material combinations become more varied, these risks increase.
Why contamination cannot be ignored
Contamination is a critical consideration in medical electronics. Flux residues and ionic contamination can lead to electrochemical migration, corrosion or intermittent electrical faults. The risk is not always immediate, with failures often developing over time, particularly in environments where humidity,
APRIL 2026 | ELECTRONICS FOR ENGINEERS
sterilisation or continuous operation are detect during initial testing but critical over the full product lifetime.
Cleaning also links directly to regulatory requirements. Medical devices must meet strict standards for reliability and, in some cases, biocompatibility. Residues remaining on a PCBA are not just a quality issue; they can also become a compliance risk.
Why contamination really cannot be ignored
As assemblies become more complex, cleaning processes need to be more controlled and repeatable. One approach increasingly used for these applications is vapour degreasing, where cleaning ionic contamination and penetrate tight conventional processes. Their low surface tension allows them to reach beneath geometries, improving cleaning effectiveness across the entire assembly.
Fluid selection is particularly important for can respond differently to cleaning material compatibility helps reduce the risk of damage while maintaining consistent cleaning performance.
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