Conformal Coating Processes and Trends

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The I-Connect007 editorial team spoke with one of Nordson ASYMTEK's conformal coating experts, Camille Sybert, to discuss where the coating industry is trending and, with the rise of Industry 4.0 and automation, how it is much less about providing the right applicator and more about addressing the entire conformal coating process.

Nolan Johnson: Camille, can you tell us a little bit about yourself?

Camille Sybert: I'm a product marketing engineer, and I’ve been with ASYMTEK for about seven years. I started in applications supporting both our precision dispensing and conformal coating. I ended up focusing on the conformal coating. Now, my responsibilities cover the product management aspects of our conformal coatings product lines as well as addressing our EMI spray solutions.

Johnson: Next, can you give us an overview of conformal coatings and the available technologies for applying them?

Sybert: Conformal coating is generally a process that's put in place because it’s required as opposed to being a nice thing to have. Its function largely serves to increase product yields in the field and the reliability of products, especially in harsh environments. Conformal coatings protect electronics from external factors, such as extreme heat, humidity, moisture, and dust. They also protect from internal factors, such as circuit board corrosion, whisker growth, and shorts within the system.

Overall, they serve as an insulation layer that makes sure that the different components stay focused and dedicated to what it is that they’re doing as opposed to getting in trouble and causing premature failures on boards. As we start to see electronics in a variety of different applications, and as we incorporate some more into things like automobiles, then the need for higher reliability in these electronic products increases significantly.

Johnson: Do standards play a big role in why conformal coating is required rather than it being just "nice to have" for cars, etc.?

Sybert: Your question addresses a number of different items that are coming up as far as what is required in the industry. The world’s increasing dependence on electronics demands that these products need higher levels of performance and capabilities. The industry accepts this and defines what those requirements and standards are. In addition to the ability to put down conformal coating, there’s also the requirement to add degrees of overall process tracking and traceability. Everything that goes into the development of these electronic components is recorded and monitored and can be researched retrospectively if an issue should arise. If there’s a problem with an electronic component that comes up down the line, that can be addressed as well as similar issues. Then, the specific source of the problem can be identified too.

Johnson: That’s an interesting point. The traceability requirement falls to the equipment, doesn’t it?

Sybert: Right, there are many different factors that go into conformal coating, which is only one piece of the entire puzzle that goes together. Currently, people in the industry talk a lot about Industry 4.0 and IoT; much of that stems from data collection and traceability. Many systems involved in the process require closed-loop controls. Now, when we talk about conformal coating, the industry tends to focus on the conformal coating machine. But conformal coating is an entire process itself from board preparation to coating. Then, your coating quality has to be maintained by whatever curing process that you put in your manufacturing line. Inspection is another critical component to verify that your coating processes are within the target.

As we talk about closed-loop controls or the move to more automated operator-less factories, pieces of equipment must be more independent in the sense that they monitor themselves. They correct internally so that you don't require operators to intervene. With automated coating inspection, you can take out a lot of operator subjectivity by setting pass/fail criteria around what you’re inspecting. You verify that you're putting the coating material where you need it to be. You're verifying that it's not where it shouldn’t be and that your final product is within your accepted tolerance. The same is true with ovens and other systems having closed-loop controls to make sure that temperature is being appropriately regulated. You don't want an incomplete cure that may potentially cause other concerns and considerations.

A lot of what's required around these pieces of equipment is that they can collect data and gather information, but also that they're able to share it and take action on that information. Nordson ASYMTEK has been big on process controls for decades. For conformal coating, we came up with laser fan width control to make sure that the coating fan pattern is within tolerance and can make adjustments. Monitoring and controlling flow rate is critically important as well as making sure that fluid temperature remains consistent, so the coating pattern is not affected by the environment; changes in environmental temperature can negatively impact your material viscosity, which would then change how your fluid comes out of the applicator.

To read the full article, which appeared in the August 2019 issue of SMT007 Magazine, click here.



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