Protecting Your PCBs: Potting or Parylene?

When it comes to electronics, the printed circuit board (PCB) is an essential component. Without the PCB, the complex components of your electronics have no way to connect to each other. Throughout the history of computing and electronics, the development of the PCB has been crucial in enabling electronic devices to become smaller, lighter, and more complex.

Because the PCB is so essential, methods for protecting and strengthening it are also essential. Printed circuit board assemblies must stand up to all the rigors of your products’ operational environments—a formidable challenge to overcome, especially for products intended for public safety or military applications. Protection is also of the utmost importance for any other applications in which your products will endure extreme conditions or hostile environments.

There are many options at your fingertips for protecting your electronic devices, especially the PCB assembly, from dangers such as physical shocks and impacts, electrical shorts, extreme temperatures, or water exposure. With all the available options, it can be challenging to keep track of the advantages and drawbacks of various protective solutions for your electronics and make an informed decision about what is suitable for your electronics.

Two such options for protecting your electronics are parylene conformal coating and electronic encapsulation, also known as potting. Both options utilize organic polymers to protect your PCB from minor impacts, corrosion, or other hazards, prevent your PCB from failing in harsh environments, and increase your PCB’s electrical performance. 

However, both have very different approaches to achieving those goals and distinct advantages over each other for specific situations. Read on to learn more about the similarities and differences between parylene and potting, along with each option’s advantages and disadvantages.

 

 

 

What is Potting in Electronics?

 

The potting most people are familiar with involves moving a plant to a new pot and burying its roots in fresh soil to ensure that it will have ample room to grow and remain healthy. In electronics, potting is much the same, except that the pot is the outer shell of your device and the soil is an insulating liquid compound. This compound, typically silicone or epoxy, covers the electronic components and then hardens to protect the device’s delicate electronic components permanently.

 

Advantages and Disadvantages of Potting

Potting your electronic components is a popular choice for protecting your circuit boards because it is easy to apply quickly in high-volume production environments. Because the compounds are laid on very thickly, they offer excellent impact resistance.

With potting, you can dramatically increase your device’s resistance against impacts and abrasions, as well as heat, chemical, and water exposure.

Potting can also make it more difficult for competitors to reverse-engineer your designs. If you pot your electronics in an opaque epoxy or silicone compound, nobody will be able to observe the layout and structure of your electronics simply by taking apart the outer shell.

There are disadvantages to using potting to protect your PCB assemblies as well, though. One such drawback is that the thick coating makes your devices much heavier and bulkier. The weight and thickness added to your electronics can also cause trouble integrating your electronics into the design of your product, especially if your goal is a slimmer, more lightweight product.

 

Potting offers:

• • High resistance to physical, thermal, and chemical hazards
  • Great protection against impacts, abrasions, water, and electrical arcing
  • Ability to prevent reverse-engineering
  • Easy and quick application in high volume production

At the cost of:

• • A significant increase in weight and size
  • Higher costs of application materials
  • Complex application process, including additional process steps for drying and curing
  • Difficulty inspecting and repairing products for QA or after manufacture

 

 

What is Parylene Conformal Coating?

 

There are many different types of conformal coatings, utilizing a wide range of polymers and application methods. Acrylics, epoxy, polyurethane, silicone, and parylene all have their own unique attributes that set them apart from each other, including their degree of heat tolerance and chemical resistance, their hardness and flexibility, and their application methods.

Among conformal coatings, parylene is generally considered the best type of coating protection for electronics. Parylene conformal coating applies an extremely thin yet powerful polymer film to your electronics using a unique process called “Chemical Vapor Deposition.” 

Using this method, a parylene conformal coating, as its name implies, conforms to every nook and cranny of your PCB’s surface area with uniform thickness and coverage and can be as thin as 0.5 microns while providing protection for the electronic components in your rugged products.

 

Advantages and Disadvantages of Parylene

Parylene has a wide range of applications in various industries and sectors due to its unique physical attributes. In the electronics industry, parylene is especially useful as a form of waterproofing as well as a precision dielectric layer.

Parylene, like most conformal coatings, is thin and lightweight. Conformal coatings tend not to put much stress on components, and their unobtrusive lightness usually does not interfere with your product’s design and form factor. Parylene conformal coatings can be applied to most material substrates and can withstand extreme temperatures and environmental stress.

A parylene coating strengthens your PCB and protects it from dust, corrosion, and moisture. Parylene coating also tends to be extremely long-lasting as well. Though parylene has high mechanical strength, because conformal coatings are not very thick, they don’t protect exceptionally well against heavy impact, abrasions, and other physical shocks.

Because of parylene’s unique vapor deposition application process, which uses a vacuum coating chamber, specialized technology is needed to apply parylene. Special care must be taken to ensure that objects are completely clean and masked, if required, before coating. This process makes parylene conformal coating most ideal for batch-style production and can make it challenging to rework products after manufacture.

 

Parylene offers:

• • A thin, uniform conformal coating with no pinholes or pooling that can be applied to any surface
  • Excellent waterproofing and dielectric layer capabilities
  • Protection from dust, salt spray, corrosion, moisture, extreme temperatures, and physical stress
  • Long lifespan

 

At the cost of:

• • A complex vapor deposition process
  • Less robust protection from physical impacts
  • Less durability and resilience
  • Not as well suited for automated, high-throughput production

 

 

Is Parylene Conformal Coating Better than Potting?

 

Choosing between potting or a parylene coating for your electronics is not a question with a simple, cut-and-dried answer. Rather, it depends entirely on the unique properties of your product, its form factor and design, its intended market, and the environments it is expected to perform within.

Both potting and parylene protect your electronics in different ways, and which of their unique advantages and disadvantages matter most to you depends on your product’s unique needs.

Potting provides a thick coating that offers excellent protection against physical shock and other hazards but may significantly increase your product’s weight and interfere with your product’s intended form factor. Thick resin coatings used in potting can protect your products from being reverse-engineered but also complicate reworking or inspection. Potting is easy to apply to high-volume products but can take a long time to dry and cure.

Parylene conformal coating is thin and lightweight, working well with small form factors, but does not hold up to physical hazards. Parylene has no drying or curing phase, though it does require specialized vapor deposition technology to apply.

 

To decide whether parylene or potting works better for you, ask yourself how much protection your PCB needs against the following:

• • Extreme temperatures
  • Water, humidity, and moisture
  • Physical shock
  • Mechanical stress
  • Chemical exposure

 

As well, ask yourself how your product will be manufactured and how it will be used in the field, including:

• • What elements it will be exposed to in use
  • The conditions of the manufacturing process, including exposure to heat and other factors
  • The form factor of your product or the design of the enclosure for your PCB
  • What other protections your device will have from environmental factors

 

Both parylene conformal coating and potting are proven and trusted solutions for ruggedizing electronics, enabling products in all sorts of industries to function well in extreme environments. Conformal coating is ideal for compact, sensitive electronics, making it an industry standard for smartphones, tablets, and other handheld or pocket-sized electronic devices. PCB potting, on the other hand, is typically used for high-voltage and extremely ruggedized electronics where size is not so much of a concern.

 

SEE ALSO: The Important Differences Between ‘Water-Resistant’, ‘Waterproof’, & ‘IPX-Rated Waterproof’

 

Should You Choose Parylene or Potting for your PCB Assembly?

The answer to this question depends entirely on your product’s unique needs. Whatever your decision, though, this is not a question to ask lightly, and your choice will significantly impact the production process for your products.

Make sure to consult experts before making your decision between parylene and potting so that you can make an informed choice and pick just the right protection method for your PCB that aligns with your budget, timeline, and other concerns.

At VSi Parylene, we believe in a transparent, friendly approach to parylene coating that puts the power of conformal coating into manufacturers’ hands. To see if parylene is the right solution for your product, Contact Us

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