What are the key questions to ask when cleaning for conformal coating?

Of all the questions I am asked related to cleaning the most frequent is

“Do I need to clean my circuit board before conformal coating?”.

If only it was simple to answer!

Generally, cleaning of a circuit board before conformal coating application is desirable. For Parylene this requirement may be even more important due to the bonding issues of the material.

However, it may not be essential.

Ultimately, the cleanliness of the circuit can be crucial for both the short-term production process and the long-term reliability of the circuit.

But, its difficult to know for sure if you need to clean until you complete some trials.

For the process it is difficult to know until you attempt to apply the conformal coating in production.

Then you will know immediately if you need cleaning since if you have problems you will see conformal coating defects like de-wetting, de-lamination and poor adhesion.

For the long-term reliability unless you want to wait until your product fails then some sort of reliability testing should be tried.

After all the purpose of the application of the conformal coating is to improve reliability.

It has less value unless the board is clean enough in the first place.


Other key questions in cleaning

There are many questions relating to conformal coating and cleanliness that are regularly asked.

These include:

  • What is being cleaned when circuit boards are washed?
  • How should I clean my electronic circuit board?
  • How do I validate my cleaning process?

If further information on these topics and the key question you can go to our free eBook by clicking Nexus conformal coating and cleaning.

If you are new to Nexus and our work on conformal coatings then a good place to go is our Start Here page.


Dr Lee Hitchens, Author of Nexus website and ebook
Dr Lee Hitchens, Author of Nexus

Dr Lee Hitchens is the author of the Nexus conformal coating website and eBook.

Send me an email at lhitchens@nexus3c.com and let me know what you think?

 

What type of problems can you have with conformal coating?

Normally, when I am working with customers I see two types of problems.

Those are problems relating to the conformal coating process and those relating to the actual product reliability.

They are two very different issues to deal with.

Conformal coating reliability problems

Ultimately, there are many factors that can affect the short, medium and long-term reliability of a circuit board.

It is not just the conformal coating that can influence this.

However, if the conformal coating material is not correctly specified at the reliability design stage then this could be the major issue and the reason for failure.

Once the product reliability requirements have been defined as part of the conformal coating design procedure then the resulting information needs to be combined with the data from the conformal coating holistic approach.

This will ensure that the risks of a failure due to the conformal coating are minimised.

if the conformal coating material is not correctly specified at the reliability design stage then this could be the major issue and the reason for failure.
If the conformal coating material is not correctly specified at the reliability design stage then this could be the major issue and the reason for failure.

Conformal coating process problems

Typical failure mechanisms in conformal coating processing normally come from the conformal coating masking process or the application process.

Conformal coating masking failures

Failures in the masking process are generally a known quantity and easy to understand.

Adopting best practice methods for conformal coating masking can help to minimise these problems.

Masking with tape and latex 1 600
Using best masking techniques can minimise some problems found in conformal coating processing

Conformal coating application failures

Failures in the conformal coating application process are very well understood.

Typical failure mechanisms include:

  • Bubbles
  • Blushing
  • Contamination
  • Capillary Flow
  • Orange Peel
  • Shadowing
  • Cracking
  • Delamination
  • De-wetting
  • Fish Eyes

Understanding and troubleshooting why these conformal coating failures occur can quickly lead to a solution to the failure in the conformal coating process.


Need help with your conformal coating process?

Contact Nexus now and let us show you how we can help you.


Dr Lee Hitchens, Author of Nexus website and ebook

Dr Lee Hitchens is the Author of the Nexus eBook and a main contributor to Nexus.

 

What are the critical points to correctly design your conformal coated circuit board to meet the highest standards?

When designing for reliability with conformal coating then there are several important areas to consider for the product:

  • Reliability Requirements
  • Life Cycle
  • Environment
  • Materials and Parts selection
  • Electrical Effects

The purpose of the conformal coating is to protect the printed circuit board. This is to increase the circuit and product reliability.

corroded circuit board
The purpose of the coating is to protect the circuit. Understanding the key points will ensure that the coating does its job

To ensure the right level of reliability is achieved with the conformal coating then a complete understanding of the design requirements for the circuit board is critical.

This should be the starting point for most engineers when considering designing for reliability.

Click designing for reliability with conformal coating to find out more.

 

Book your place on the Nexus Webinar: Conformal Coating Guide to Design, Application & Reliability which will be held on the 12th November 2012

The Nexus webinar: Conformal Coating Guide to Design, Application & Reliability will be held on the 12th November. 

Conformal coating may be a new process to many people and its important to have a good grounding in the fundamentals before embarking on the use of coatings. An incorrect choice at the design stage can add significant cost to the product without the desired benefits. Correct selection of components and application techniques can significantly reduce cost by reducing or eliminating masking steps. A key step during design is to assess the effective reliability prior to going into full production.

Topics will include:

Why conformal coating is necessary
Types of material and their benefits
Design engineers check list
Coating application methods
Testing product reliability

Click Conformal Coating Webinars: Conformal Coating Guide to Design, Application & Reliability for further information

Nexus Series of Conformal Coating Webinars: Conformal Coating Guide to Design, Application and Reliability

Nexus are to hold a series of webinars on conformal coating topics in the Autumn of 2012.The series of four online conformal coating webinars will cover the following topics and each last 90 min. The next webinar will be:

Conformal Coating Guide to Design, Application & Reliability
12th November 2012

Conformal coating may be a new process to many people and its important to have a good grounding in the fundamentals before embarking on the use of coatings. An incorrect choice at the design stage can add significant cost to the product without the desired benefits. Correct selection of components and application techniques can significantly reduce cost by reducing or eliminating masking steps. A key step during design is to assess the effective reliability prior to going into full production.

Topics will include:

Why conformal coating is necessary
Types of material and their benefits
Design engineers check list
Coating application methods
Testing product reliability

Click Conformal Coating Webinars: Conformal Coating Guide to Design, Application & Reliability for further information

Nexus Webinars: Conformal Coating Guide to Design, Application and Reliability

Nexus are to hold a series of webinars on conformal coating topics in the Autumn of 2012.The series of four online conformal coating webinars will cover the following topics and each last 90 min. The first of the online training webinars will be:

Conformal Coating Guide to Design, Application & Reliability
12th November 2012

Conformal coating may be a new process to many people and its important to have a good grounding in the fundamentals before embarking on the use of coatings. An incorrect choice at the design stage can add significant cost to the product without the desired benefits. Correct selection of components and application techniques can significantly reduce cost by reducing or eliminating masking steps. A key step during design is to assess the effective reliability prior to going into full production.

Topics will include:

Why conformal coating is necessary
Types of material and their benefits
Design engineers check list
Coating application methods
Testing product reliability

Please click online conformal coating webinars for further information.