Cleaning PCBAs before applying conformal coating is crucial for the reliability and performance of electronic devices. Conformal coatings protect PCBAs from environmental factors like moisture, dust, chemicals, and corrosion, enhancing their longevity and preventing product returns. However, inadequate cleaning can lead to problems such as contamination, coating delamination, reduced moisture protection, and increased corrosion vulnerability.
Even "no-clean" solder pastes can interfere with coating adhesion, negatively impacting the board's performance. Insufficient cleaning can also cause the formation of dendrites, microscopic conductive filaments that can bridge conductive traces, leading to short circuits, electrical failures, and compromised functionality.
4 Ways to clean PCBS
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Manual cleaning This can involve aerosol or pump sprays, or solvents in a pan or tray. Agitation can be applied with a brush, swab or wipe. |
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Ultrasonic This method uses sound waves to create bubbles, which implode on the PCBA surface to break up the flux residues. |
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Vapor degreasing The cleaning is done either in the vapor phase of a solvent or submerged in a sump, which often includes ultrasonic action. |
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Batch or inline systems Spray equipment with water-based cleaners to wash, rinse, and dry the PCBAs. |
