Posted by Jake Hinojoza on Mar 27, 2018 9:00:00 AM

Small PCBs and Parylene

As our electronics advance, they become smaller and smaller. The inner workings of electronics, however tiny, still need to be protected. Printed circuit boards, or PCBs, are the little pieces that make electronics run. To protect them from outside threats, they are covered in what is known as a conformal coating, or a non-conducive film covering. Parylene is a unique conformal coating that is applied as a vapor. Read on to learn more.

Advantages of Parylene

Parylene is unlike other conformal coatings because it is applied as a vapor. The unique application process allows it to thoroughly cover the entires surface of a PCB. In a room temperatures space, the deposition is used and grows on the electronic component. Plastics, ceramics, metals, and fabrics can all have parylene applied to them.

As electronics begin to grow smaller in size parylene is taking a lead role in conformal coatings. When applied, it is thinner than a dollar bill or even human hair. When it comes to choosing a conformal coating, most industry experts will favor parylene.

The Purpose of Conformal Coatings

A parylene conformal coating is applied to an electronic PCB that needs protection from exposure to environmental threats such as dust, temperature, and moisture. Conformal coatings can also protect exposition of PCBs in fraught situations. Sometimes these are electrical currents, mechanical forces, or chemicals. The protection will prevent corrosion and oxidization. It can also extend the life of an electronic.

Problems with Liquid Coatings

It’s important to look at the drawbacks of liquid coating such as epoxy, silicone, and acrylics. Liquid coatings are applied through a dip or spray process and then cure after. Unlike parylene which cures uniformly in a micro-thin layer, liquid applications can be uneven leave potential pinholes that expose the PCB. Liquid coatings also contain additives that reduce the durability and continue to gas-off after application.

What Makes Parylene Different

Since there is such a wide variety of conformal coating types, it's important to understand what makes parylene stand out. Parylene is a reliable, long-lasting coating that goes on clear and pinhole-free--not to mention it can be controlled closely for thickness and can coat even the most awkward or unusual shapes and areas. This is made possible because of a few unique details in the way parylene is applied and used. Here's what the parylene experts noticed when comparing parylene to other conformal coatings.

  • Deposition. Parylene is placed with a unique chemical vapor deposition process, which is why this conformal coating can so reliably coat even the most difficult areas. The coating goes on lightweight and is placed in layers of varying thickness, so there will never be too much or too little protection--all without adding significant mass that could interrupt the function of the product. This is one of the reasons parylene is the first choice.

  • Types. One of the reasons why parylene is so widely used is that it comes in different types, meaning that there is a type of parylene for every job. Parylene N provides high dielectric strength and a dielectric constant that does not vary with changes in frequency. Best selection where greater coating protection is required. Parylene C provides a combination of properties, plus a very low permeability to moisture, chemicals, and corrosive gasses.

  • Protection. At the end of the day, parylene is favored over other conformal coatings because it's good at what it does. It can survive high temperatures and other extreme conditions, it protects against everything from chemicals to moisture, and it remains strong and reliable.

Parylene is used just about everywhere for a little bit of everything and considering its long list of benefits and positive characteristics, it's no surprise that experts in every field turn to parylene coating first.

Parylene is the conformal coating of choice for many of the above reasons. If you’re ready to move forward with a conformal coating project, contact us today.

Jake Hinojoza

Written by Jake Hinojoza

Jake received his Bachelors of Business Administration from California State Polytechnic and has been with Advanced Coating since 2009.

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