Find out why it’s important to waterproof electronics.
Explore common types of waterproofing for electronic materials.
Learn how to choose the right waterproofing material for your application.
It is safe to say, in our tech-obsessed society, that everyone knows electronics and water typically do not mix well. Results can range from inconvenient to fatal. Talk to anyone and they probably have a story about dropping a cell phone in the pool or knocking a mug of coffee onto their keyboard or laptop. Stories of electronics failing after exposure to liquid, moisture, or humidity are unfortunately common.
As they say, “Necessity is the mother of invention,” and this is especially true here. Over the years we have come up with some great ways of protecting the electronic devices we rely so heavily on from their main nemesis: water. This article will discuss some common ways of waterproofing electronics materials to allow your designs to be successful even in wet or humid environments.
Why Do You Need to Waterproof Electronics?
Most electronics will not survive water exposure.
Smartphones contain thousands of components connected with tiny, delicate circuits. They are one of the most powerful consumer electronics that has ever been invented. Yet, try soaking an ordinary smartphone in a bucket of water and you’ll quickly learn how vulnerable they can be.
If you’re lucky, your smartphone is smart enough to shut itself off to prevent damage. Otherwise, you can bid farewell to a pricey piece of sophisticated electronics.
In a dry environment, electricity flows as intended through the circuitry. However, the presence of water changes the connectivity between various circuits. In other words, water causes short circuits in electronics, which almost always result in lasting damage.
The breakdown of electronics due to water exposure isn’t always as dramatic as dropping a phone into the puddle. Many commercial installations are done in highly humid environments. In some cases, the moisture in the air collects on the PCB and gradually forms short circuits across various conductors.
Either way, the importance of waterproofing a PCB should be considered, particularly if the electronics are used in critical applications.
Common Compounds for Waterproofing Electronics Materials
An epoxy resin coating on a component.
When it comes to waterproofing electronics materials, the following are the most common types in the industry:
Epoxy is commonly used as a potting material for electronics. In epoxy potting, the entire PCB is encased in the material. This method ensures that the electronics are waterproof while providing great mechanical strength.
Silicone is used in potting or as a conformal coating. It lacks the mechanical strength of epoxy but is substantially more flexible.
Choose urethane if you need a waterproofing material that strikes a balance between mechanical strength and flexibility.
Acrylic is a great method to waterproof PCBs due to its quick-drying nature and ease of rework. It is also highly resistant to humidity.
When applied, para-xylylene provides a very thin layer with excellent protection against moisture. However, applying para-xylylene on PCB is costly and difficult, so it may not be well-suited for many designs.
Fluoropolymer is a nano-coat that rivals the thickness of para-xylylene and has a lower process cost.
Choosing the Right Method for Waterproofing Electronics Materials
Humid and hot environments require waterproofing materials with greater temperature tolerance.
The materials we discussed will prevent moisture from damaging the electronics, but how do you know which is the right solution for you?
It all depends on the nature of the product, your budget, and your requirements. Acrylic goes well in most applications as it’s cheap and easily repairable. However, if you need something more flexible, silicone will be a better choice.
Lastly, water isn’t the only concern when it comes to PCB protection. The PCB may be exposed to extreme heat or chemicals when deployed. In such cases, acrylic is not a good choice as it does not tolerate high temperatures well.
When total protection is required in extreme temperature, para-xylylene will be a better choice. But, the downside is that it is a costly solution.
Waterproofing electronics materials helps to mitigate damage from exposure to moisture, but a decent PCB design software is needed to handle all of the other issues that come first. Before you can worry about how your design will react to moisture, you need to be sure you have a sound design. OrCAD PCB designer can run a strict DRC check to ensure the circuit complies with best practices, in addition to the full suite of other features and capabilities it has.
If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.