In this Key Polymer podcast episode, Melissa Mitchell discusses how Tough-Seal potting compounds help protect open and semi-enclosed electronic assemblies. She covers moisture, dust, handling, electrical insulation, signal transmission, serviceability, and why side-by-side reliability testing can reveal the value of encapsulation.
John Maher: Hi, I’m John Maher, and I’m here today with Melissa Mitchell, product manager and senior engineer at Key Polymer, a manufacturer of electronic potting compounds, adhesives, coatings, and other chemical compounds. Today, we’re discussing potting compounds for open electronics. Welcome, Melissa.
Melissa Mitchell: Hey, John. How are you? Good to be here.
Why Open and Semi-Enclosed Electronics Are Vulnerable
John: Good, thanks. Melissa, open and semi-enclosed electronics are often exposed to things like moisture, dust, and handling. What makes those types of applications especially vulnerable?
Melissa: So, for applications that see this type of contamination, it usually causes issues with the function of the board and the electronics themselves and they’ll usually see field failures or see issues with the part performing the way it’s supposed to. So typically whenever there’s some contaminant, it’s always something to consider as being negative to affect any electronic sensor or electronic assembly.
Potting Compounds for Reliable Electronic Performance
John: And how can potting compounds help protect components while still supporting reliable electronic performance?
Melissa: So a potting compound is a protection that can be applied to the electronic components to protect the performance. So if you have specific assembly, whether it’s a wire harness, a sensor, just a straight printed circuit board in an application, that can be protected very easily by just adding the potting compound to the assembly and it will make sure that those components have a tight seal around them.
The potting compound will flow around all the components and create a solid seal after it cures. And it will stop that moisture, dust and any other debris or chemicals or contaminants from getting in to the components and causing damage.
Electrical Insulation in Potting Compounds
John: And typically the potting compound doesn’t have any electrical conductivity, so it’s not interfering with the electronics at all.
Melissa: Correct. So, typicaly, potting compounds are polymer based with no additives that would cause any electrical disruption or issues from that perspective. The Tough-Seal potting compounds are more electrically insulative. People think, are they electrically conductive, or electrically insulative? They’re electrically insulative.
Potting Sensor Arrays, Relays, and Instrument Panels
John: And what are some of the challenges that come up when potting things like sensor arrays and relay systems, instrument panels and things like that that may not have full enclosures?
Melissa: So, with things like arrays where you need transmission of a signal, Tough-Seal is a great choice. We’ve had several customers that have done pretty extensive testing and Tough-Seal does extremely well allowing the transmittance of the different signals through, and doesn’t disrupt the performance of the part or the final product.
Serviceability vs. Long-Term Encapsulation Protection
John: And how should engineers think about serviceability versus long-term protection when they’re deciding whether to encapsulate exposed electronics? Once something is encapsulated in a potting compound, you can really no longer go and service that electronic printed circuit board. So is there a trade-off there where a company has to decide, “Hey, it’s okay if there’s a problem with this, we’re just going to replace the whole thing.” Or are there certain situations where they say, “No, we’re better off leaving the potting compound off of this in order for us to be able to service this part down the road?”
Melissa: I think for the engineers that are working on these types of projects, they really need to take a look and try to identify what the problem is that they’re servicing. If it’s a problem that is unrelated to a contaminant affecting the part, moisture, humidity, vibration, thermal shock, thermal cycling, things like that where they’re seeing components damaged because of a rotational force that’s on the part or a thermal shock issue or thermal cycling.
If they can identify these failures that need servicing, they can determine if it’s something that the potting compound can eliminate or reduce the number of those failures. If there are other issues unrelated to those things that require service, just a specific part times out because it’s through its lifecycle, that would be a different instance where a part would have to be replaced.
So I think really looking at the cause and what can be done to prevent it is a good step into trying to determine whether a potting compound is right for the application.
There are instances when potting compound, even though this is a thermoset, there are ways to pot the board where you can reenter. We have helped a couple customers do things like, that adding some additives below the potting compound and being able to remove a layer with a filler below. So there are things that can be done to reenter and we could definitely talk to customers about that if they wanted to investigate that further.
Avoiding Protection Gaps in Semi-Enclosed Devices
John: And are there some common mistakes that companies make when they assume that a semi-enclosed or enclosed device is maybe protected enough without having to do the potting compound?
Melissa: I think that sometimes people will, for example, use just a conformal coating and they won’t put the conformal coating through a great battery of tests or they might do some other design changes that they think would protect enough. But I think where potting compound like Tough-Seal is a very effective long-term solution, I think it’s something that the engineers should reconsider investigating if they hadn’t considered it before from the perspective of doing testing and investigating from a reliability standpoint and really looking at unprotected versus protected side by side, that’s a good comparison that they would be able to determine the positive effects of potting compounds.
John: Certainly things like moisture and fine dust are things that are … They get into everything, even if you’re trying to block those out. So there’s probably a lot of applications where people think, “Oh yeah, well, they’re in that enclosure, they’ll probably be fine”, but moisture has a way of getting into just about anything.
Melissa: Yes. I think really looking at what the root cause of failures are is definitely a good way to investigate and understand whether potting compounds are going to be right for you. I can’t think of too many instances when potting compounds aren’t the right direction to move forward to eliminate some of the issues that people have and to make sure that your intellectual property is protected, your design, your engineering, your electronics are all protected. It’s very few and far between that a potting compound wouldn’t be recommended for potting applications for electronics.
John: All right, well, that’s really great information, Melissa. Thanks again for speaking with me today.
Melissa: Thanks, John.
John: And for more information, you can visit the Key Polymer website at keypolymer.com or call 978-683-9411.