Circuit board inspection of conformal coating is the most critical process in the complete production line.
Get this wrong and the reliability of the board can be significantly effected.
Inspection should be carried out on completion of the coating process. However, it is often a neglected stage of the conformal coating production line.
The International standards such as IPC A 610 and IPC CC 830 are explicit in their requirements for conformal coating inspection. Yet, few companies actually inspect to the required level or indeed understand what is required.
Traditional conformal coatings protect the circuit well if they are selected correctly. However, where the coating is not applied there is little or no protection.
Nano coatings (FC), ultra thin coatings of thickness <2μm, provide hydrophobic properties and don’t need masking.
The lack of need for masking is due to the coating thickness being so thin that there is no resistance to removing the material. This means the FC can coat all of the circuit including connectors and offer the protection of the coating.
However, this very fact means the FC coating is delicate to handle and may not provide the long term reliability needed like a traditional coating.
So, what if we could combine the two materials and have the properties of both?
The circuit board would have:
The long term protection due the traditional conformal coating
The hydrophobic nature due to the FC coating
Protection all across the circuit board
Nexus have been experimenting wth dual coating with both traditional conformal coatings and ultra-thin coatings.
The results are extremely interesting for potentially increasing the protection of the circuit without adding a significant amount of cost to the process.
Analysing your conformal coating production process, whether its a conformal coating line or a Parylene batch system, can create huge benefits due to improvements made in the production performance.
Using our expert knowledge and experience from Nexus, we can examine your individual production processes and examine your output for your coating line.
This can save you money, time, and improve quality, depending on your needs.
A typical audit would include:
A site visit to audit your conformal coating facilities and processes surrounding the conformal coating area.
Discussions with staff members regarding the conformal coating processes, understanding their needs for production, the requirements for the product to be protected by the conformal coating and any other issues such as commercial or health & safety restraints
Analysis of the conformal coating process findings with recommendations for further improvements delivered in a report for future reference
We would work with you to understand your requirements an priorities. We can then tailor the system to fit your needs, whilst employing the best knowledge available for your field of production.
Let us help you and audit your conformal coating process line.
Discolouration of a conformal coating can be a natural phenomenon due to the nature of the resin used. For example, a polyurethane conformal coating will naturally darken and go brown with time due to its inherent properties.
However, a change in the colour or loss of transparency of the conformal coating that adversely affects the performance or the identification of the components below the coating can be classed as a defect.
Causes of discolouration in conformal coating include UV light exposure and prolonged exposure to contaminants. But, this problem can be prevented with the right measures.