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Conformal Coating Removal from Fixtures
When it becomes necessary to remove a conformal coating, it can result in a costly ordeal. The very properties that describe a quality conformal coating – tight coverage, strong adhesion, conformance to the contours of variably-shaped surfaces, and resistance to removal through chemical or mechanical – tell the exact reasons why removal is extremely difficult.
Types of coatings today vary from silicone, acrylic, urethane, epoxy, paralene, and more. Each presents their own challenges for removal. Some will only respond to mechanical methods, while others require a chemical solvent.
There are circumstances, however, when conformal coating removal is not only necessary but expected. Factory application processes can be dipping, spraying, or vapor deposit.
Each invariably involves a fixture – a point of attachment used to secure the PCB to the assembly line machinery while the coating is applied. Whether a platform, tray, or hook, the build-up of overspray to the exposed fixture degrades its usability and must be accounted for in the manufacturing process.
What does the removal of each have in common?
Cost. Mess. Hassle.
What is a Conformal Coating?
Conformal coatings provide essential protection for printed circuit boards for working and environmental conditions of all types.
The coating functions as a layer of shielding from wind, ice, humidity, oil, chemical, abrasion and other factors and forces that can damage equipment.
There are circumstances, when conformal coating removal is not only necessary, but expected. Factory application processes can be dipping, spraying, or vapor deposit. Each invariably involves a fixture – a point of attachment used to secure the PCB to the assembly line machinery while the coating is applied.
Whether a platform, tray, or hook, the build up of overspray to the exposed fixture degrades its usability, and must be accounted for in the manufacturing process.
Precise and effective on all coating types, plasma removal is the gold standard, for which much gold is required. While ideal for high-end projects and exacting removal of coatings on existing, expensive circuit boards, plasma removal is disproportionately expensive for mass-production work needed for fixture cleanup.
Mechanical peeling sand, scrape or cut conformal coatings from surfaces. They are by far the least reliable and accurate option. Whether done in a time-consuming manual process, or with automated machinery that much be constantly calibrated and re-sharpened, mechanical conformal coating removal is only recommended for one-time repairs or prototyping – not industrial processes.
Laser ablation has the advantage of very high accuracy, at the cost of time. Using pulses of laser energy that each remove only a few microns of material, ablation is the least time-effective solution, but often the only truly effective one for paralene-based conformal coatings.
Micro abrasive blasting uses focused inert gases with a concentration of an abrasive media to erode conformal coatings. While effective on all five types of coatings, typically it is time-consuming, damaging to fixture that have detailed surface details, and most susceptible to errors arriving from uneven layers of the coating being removed. Often the most effective for epoxies, which resist the majority of chemical or heat-based techniques.
The most common form of conformal coating removal, chemical solvents are typically used for most liquid process (dipping) coatings, based on silicone, urethane or acrylic. The difficulty of removing a coating is typically directly related to the strength and durability of the coating. The better the protection, the harder it is to remove.
Acryilic resin coatings are the easiest to remove, and pair with a standard butyrolactone solvent.
Silicone coatings pair with methylene chloride solvents, occasionally requiring a specially made concotion.
Urethane coatings pair with the strongest solvents, typically either glycol ether-base alkaline or methanol-base/alkaline solvents
Conformal coatings based on epoxy or paralene generally do not respond to chemical solvents.
Besides considerations of safe handling of corrosive chemicals, chemical solvents, as a rule, promote the rapid deterioration of the base fixture itself. Careful selection must be made to select a solvent that is not too mild, yet not too corrosive – occasionally requiring a custom-made chemical composition.
Don’t just take our word for it:
Stop wasting time. Conformal Coating Removal –
Easy and Hassle-Free with Nanoslic.
Pre-treating fixtures with NanoSlic’s unique hybrid formula allows for coatings to be removed with a minimum of hassle.
Chemical solvents, microabrasion, laser ablation and mechanical peeling techniques each have significant downsides in conformal coating removal, from damaging components to discolorations and warping to expensive removal equipment.
The key to our proprietary formula is the nanometer-thick hydrophobic and oleophobic outer shell.
It resists adherence to every type of conformal coating currently in use. NanoSlic utilizes a ceramic platform chemistry meant to withstand some of the harshest environmental factors. Because it repels both water and oil-based substances, you never have to worry about scraping off any unwanted coatings.
Like peeling a banana, you simply and easily shed the overspray, and the fixture is ready to use again.
Nanoslic provides an essential layer of protection, smoothly contouring the fixture surface to present an ideal surface for the removal of the overspray coating.