To remove parylene coating safely, effectively, and efficiently, there are a few important things to keep in mind. Today, we'll cover the three basic types of conformal coating removal, as well as everything you need to know to be successful using each one.
Why Removing Parylene is Tricky
Parylene coating is known for its strength, reliability, and longevity--all good things when it's being used in aerospace, military, or other high-intensity industries. However, when it comes to removal, all of those once-beneficial characteristics can work against you in many ways. That's why it's necessary to do your research on the three main approaches to conformal coating removal: chemical, thermal, and mechanical. Finding the best method means that parylene can be just as pain-free coming off as it was going on.
Parylene coating is designed to resist chemical degradation, which means that chemical removal must be careful and specialized in showing results. There is, however, one option: Tetrahydrofuran, an organic solvent that softens and loosens the coating from the substrate surface. Extreme caution must be taken when using Tetrahydrofuran, and it is recommended for complete coating removal only.
In addition to being highly chemical-resistant, parylene also boasts unrivaled levels of thermal protection, up to 500C for some types. Despite this characteristic, a soldering iron or high-temperature oven can be an effective option for removing parylene coating in small, specific areas.
Mechanical removal is the most popular -- and perhaps the simplest -- method available. It essentially requires you to physically scrape, peel, and pick the surface of the coating. This makes it a safer alternative to some of the more complicated removal methods, lending itself to the removal of both small areas and entire surfaces.