Applications are becoming increasingly demanding, particularly in terms of operating voltage, requiring perfect insulation between board elements (400 V and beyond).
The protective coating therefore plays an essential and increasingly crucial role in ensuring durability
The Challenge: Dewetting compromising reliability
Our client, a PCBA manufacturer for defense applications, was facing a critical issue on its production lines.
During the coating application, certain areas of the boards showed dewetting defects, with the coating retracting and leaving zones partially uncovered.
The defect rate varied between 5% and 50% of the boards due to dewetting and was especially difficult to detect in advance before coating.
This issue led to significant consequences for our client:
Costly scrap, as each board had high added value
Delivery delays or uncertainties, with manual touch-ups or rework required
Risk of non-compliance with defense industry standards
Lack of process control
Zero defects is mandatory
There were also concerns about the lifetime of “OK” boards. These were legitimate questions, and quality had to come first to ensure product reliability.
Diagnosis at the EXELSIUS lab: insufficient surface tension
To analyze the dewetting issue and find a suitable solution, we invited the client to perform tests at our laboratory in Mouans-Sartoux, France.
Our analysis revealed that the surface tension of the client’s PCBAs was too low to ensure proper coating adhesion.
One main factor was identified:
Local surface changes caused by board handling and storage
Root causes may vary: PCB process, reflow process, handling, external contamination…
With surface tension too low, the coating failed to stick consistently, leading to dewetting
The GENIUS solution by EXELSIUS: surface activation with atmospheric plasma
GENIUS uses atmospheric plasma technology to increase surface tension.
Immediate increase in surface tension
Optimal wettability for better coating and adhesive bonding
The GENIUS torch delivers plasma directly to the PCBA, preserving the physical and electrical integrity of components.
Integrating the GENIUS solution into the production line
Following successful tests, GENIUS was implemented directly on our client’s production line upstream of the coating step.
Thanks to its fast and selective treatment and automatic plasma path programming via embedded intelligence, GENIUS is adapted perfectly to the client’s constraints.
Results: dewetting eliminated, PCBA integrity ensured, and quality restored for the client
Just a few weeks after integrating GENIUS into its production line, our client reported clear improvement
Dewetting issue fully resolved
Uniform coating coverage across all boards
Elimination of manual rework and significant reduction of coating-related scrap
Full compliance with defense industry standards
A stable, controlled process ensuring 100% treatment across all production boards
Conclusion: plasma technology for defense-grade PCBAs
With the support of our teams and the integration of GENIUS plasma technology, this PCBA manufacturer permanently resolved the dewetting issue. Their boards now receive a consistent, high-quality coating that meets the strict requirements of their industry, ensuring complete integrity without compromise.
Your process partner in the electronics industry, supports PCBA manufacturers at every stage: diagnosis, equipment selection, integration, installation, and maintenance. We develop reliable, long-term solutions tailored to your sector’s demands.
