In this Key Polymer podcast episode, John Maher speaks with Melissa Mitchell about how potting compounds protect everyday electronics in control boxes, connectors, PCBs, power supplies, and related applications. They discuss common failure modes, the questions engineers should answer when selecting a formulation, and how customizable Tough-Seal compounds can support adhesion, insulation, thermal management, and field reliability.
John Maher: Hi, I’m John Maher. 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 general sealing and potting applications. Welcome, Melissa.
Melissa Mitchell: Hey, John. How are you? Good to be here.
Common Electronic Failures Potting Compounds Help Prevent
John: Good, thanks. So what are some of the most common electronic failures that potting compounds help prevent in everyday control boxes, connectors, PCBs, power supplies, other typical applications for potting compounds?
Melissa: So the typical failures that are seen are usually related to most of the time environmental factors. So moisture, humidity, or contaminants and chemicals getting into the electronic board or into the sensors. Or sometimes you can have a buildup of dust and fiber that causes some major temperature changes, that can cause it. From a mechanical standpoint, vibration or rotational forces can cause different solder joints or different components to pull from the board or crack.
Electrical insulation sometimes is an issue and sometimes from a thermal management standpoint, like if you see temperature changes when the part is in service or in its final application, if it’s exposed to temperatures that go down to minus 40C and up to 150C and back and forth and cycling from temperatures that are low to temperatures that are high, you can see damage to electronics or sometimes you can see a thermal shock where something will go from a high temperature and just drop to a really cold temperature.
If something’s exposed to being in a state where it’s in a garage and then it’s out in the cold, for specific automotive type applications, and you see that drastic drop in temperature, you can see issues with electronics and then potting would help resolve some of those issues that you could see.
Choosing the Right Potting Compound Formulation
John: Okay. And so when a customer comes to Key Polymer with a general sealing or potting challenge, what’s some of the information that you need in order to recommend the right formulation? Because I know that you have a large number of different formulations of the Tough-Seal potting compound and they’re all used in different applications.
Melissa: So what I typically will start is asking the customer if they are currently using a potting compound or if they are not using a compound yet. So if they’re currently using a potting compound, then the line of questioning starts off a little differently where I want to know why are you reaching out to us? Are you seeing issues with your existing potting compound? Are you seeing failures or problems? And try to understand what those problems are.
And then from there it would be the same as if it were a new customer per se. So I would try to find out from the customer exactly what the application is and understand where the product is being used or the final product is being used, whether it’s a sensor that’s going into a marine application or an automotive application or in an application that is outdoors where you’re monitoring something in the environment, whether it’s an LED light or a wire harness, we’d need to know those specific details of the product’s use.
Then we would want to know, are there specific temperatures that this is going to be exposed to? Are there operating temperatures that the part is going to see so we can understand the requirements from that standpoint? And then looking at where the application is, is it going to see heat, humidity? Is it going to be exposed to chemicals? If it’s exposed to chemicals, is it going to be immersed in a chemical or is the part only going to be splashed with chemicals?
We need to understand what the housing material is. So the circuit board goes into a housing. What is that material? We need to understand if there are wires and all of these things are important because we really want to know what those materials are so that we can pick a material that’s going to have good adhesion. And then from understanding the size and thickness so we can calculate the volume of material the customer’s going to use, also need to understand if there’s any certifications required like UL certification or if there’s any specific compliance requirements.
So there are a lot of questions that kind of go into understanding what the customer needs, which all plays a part in us selecting the correct potting compound for the customer’s application.
John: Right. So it’s a lot more than just what is the application and what are the conditions that this electronic component that you have are going to be subjected to. That’s part of it, but then things like the housing that it’s inside and if there are wires coming out of it and things like all of those things enter into the equation as well. Right.
Melissa: It enters into the equation. It sounds very complicated, but once we go through the questions, it’s a super easy process to select a material. Sometimes we’ll recommend one material, sometimes we might recommend a couple different materials for the customer to do testing on and then using the materials easy. So like I said, it sounds very complicated as we’re going through these questions, but to be able to tackle all of these questions makes the selection more accurate to be successful in the product itself.
So, we certainly want people to work with us so we can figure it out and make their part more successful in the field so customers don’t see field failures. And that’s what all of these questions and understanding the process and the product are, it’s what keeps the product running in the field.
Custom Tough-Seal Compounds and Production Efficiency
John: And how does a customizable compound like Tough-Seal help manufacturers protect components without overcomplicating their whole production process?
Melissa: So, for example, we talked about some of the detailed things that affect the performance or can cause failures. So selecting a potting compound of the right hardness would make sure that we don’t see cracking over time in the potting compound as it’s going through thermal cycling changes. It makes sure that you don’t see extra stresses in the components or induce stresses in the components that could cause cracking at solder joints or other components to pull from the board itself or from the electronic assembly.
So things like that, selecting the right viscosity to make sure that the material flows around all the components properly and gives the product a final seal that resists moisture, contaminants, debris, chemicals and all of those things. And then from a thermal stress standpoint, potting compounds can provide some relief from thermal conductivity. I know a lot of times customers will manage some of the heat that’s generated on the board itself with heat sinks and things like that, but potting compounds can help with that.
And then potting compounds can also help with electrical stresses by providing some electrical insulation in the part. So it doesn’t overcomplicate the process. It actually makes it less complicated for having to design around all these potential problems in the field because the potting compound covers a lot of these issues eliminates the worry of these issues becoming problems in the field and causing failures.
John: Right. So that’s why you take the extra time to go through that whole selection process and find the right one for the application because then it makes the production process much easier and simple.
Melissa: Right. And from a production process standpoint, we do factor in the size of the board or the size of the housing or the connector or whatever components we’re filling and we try to work to help make the potting process not hinder the manufacturing process. So we have a lot of experience with recommendations on making the process as seamless as possible without inflicting too much extra in the production process piece.
Balancing Flexibility, Hardness, Adhesion, and Insulation
John: Are there trade-offs that engineers should think about when they’re choosing between flexibility and hardness and adhesion, thermal performance and electrical insulation? Is it difficult sometimes to find one Tough-Seal potting compound that kind of hits the right spot for all of those things?
Melissa: So it can be challenging because there are a lot of boxes that have to be checked to make the product successful. So we try to manage with the different viscosities, the different hardnesses that we have to offer. Some of the materials have different degrees of adhesion with certain substrates. They have different thermal performances. So we can kind of dial it in and there really doesn’t always have to be a trade-off, which is really great.
And like I said earlier, there are times when there might be one or two potting compounds that on paper look like they’ll work, but we’re very happy to provide samples of multiple products so that customers can test what is going to work in their specific application. We can’t always predict exactly what is going to happen for sure in the final evaluation and performance testing or reliability testing that the customer does, but we have a pretty good idea with all the experience and applications on where to direct people and what to try.
And there’s not always a lot of trade-offs because there’s usually something within our formulation database that will work and be successful.
Tamper Resistance and Protection of Intellectual Property
And one thing, John, that I really should have mentioned before, all of these things with the performance of protection that a potting compound offers, one of the biggest things that people don’t think about is that it provides some tamper resistance for their part and some protection of their intellectual properties.
So not only does it provide all kinds of protection from thermal, electrical, mechanical, and stressors like that, environmentally, that can affect the product, it also protects the integrity of your product from an intellectual property standpoint. So people can’t tamper with your part, people can’t steal your engineering designs. It’s another degree of protection for your product and it just provides an extra layer of protection.
When to Add Encapsulation to Electronic Designs
John: Right. So for companies that have never used a potting compound before, what are some of the signs that might suggest to them that they should consider adding encapsulation as part of their design?
Melissa: So when customers that aren’t using a potting compound have parts coming back from customers where solder joints are breaking or components are pulling off the board or they’re seeing failures because it’s in an application where something’s being used in a high humidity environment or in an area where a part might be exposed to some vapor or chemical. When these failures are repeatedly happening with a product rather than try to just change the design of your actual engineered electronics, it makes sense to really consider and try and test and do some performance and reliability testing on the improvements that a potting compound can make.
So companies sometimes see these failures, and I’ve seen companies try to redesign their board or their components or their wire harness or whatever. They’ll redesign things to try to correct what they’re seeing in the field. And all they need to do sometimes is just use a potting compound that can help dissipate some heat or a potting compound that can provide that extra protection at solder joints or vibration protection.
And it does eliminate those field failures that continue to sprout up in the field.
John: All right, well, that’s really great information, Melissa. Thanks again for speaking with me today.
Melissa: My pleasure.
John: And for more information, you can visit the Key Polymer website at keypolymer.com or call 978-683-9411.