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PCBA protective coatings

Protective coatings safeguard and maintain the functionality of the PCBAs and thus ensure the success of your product.
Depending on the place of use and the conditions prevailing there, the circuit board undergoes a specific stress and requires a protective coating to be able to maintain the full range of functions in the long term.
The selection of the appropriate process in the suitable layer thickness or with selective recesses and the required material properties in terms of the protective effect are decisive for the lasting functionality of assemblies.
We are familiar with the variety of applications and have specialised in supporting our customers in finding the suitable process and the required material - with a sample board on request.
In this process, all parameters of varying strength of the individual requirement for weather-related, chemical and mechanical protective effects (e.g. condensation / dust deposits / scratch resistance / harmful gases etc.) are combined with the required functionality (e.g. conductivity / transparency LED/MOST / high-frequency suitability etc.) to determine the requirement. Our configurator analyses the requirements in the first step. Our sales department supports the precise selection in the next step.
Our development department works out individual solutions for specific applications - with the production of a sample board.

What kind of protection do your electronics need?
Depending on the type and severity of the application, the board is exposed to different, single or multiple stresses and is attacked in the process.
The effects of this can include electrochemical migration, corrosion, voltage flashover or resistance reduction and can lead to failures.
Weather-related attacks, e.g. through condensation, moisture, temperature shock / salty air etc.
Chemical attacks, e.g. by fluxes or solvents / harmful gases / oils / fuels / alkalis / acids etc.
Mechanical attacks e.g. dust / dirt particles / contact / scratches / impacts etc.
At the same time, the protective coating must be permeable enough to fulfil the product-dependent functionality. These requirements are, for example, maintaining the conductivity of switches and plug-in contacts, ensuring permanent transparency for LEDs or MOST and not impairing high-frequency compatibility. Not every type of protective coating can achieve this.
In addition, there are production-related parameters such as solderability, required freedom from silicone, necessary recessing of components, does a black light check have to be carried out? And the question always arises. Should the assembly remain repairable?

Then we also have process requirements. Are short process times and thus fast drying times required? Does the protective coating application have to be introduced into already existing process sequences? How expensive is the entire process?
Ultimately, the choice must be a system that combines most of the requirements. Puretecs has a very wide range of these. From ultra-thin protective coatings to full potting. Our configurator helps simplify the selection.

 

pdf icon 48Introduction to Fluoropolymer coating for the reliable protection of electronic circuits and assemblies >> download

 

 

1Ultra-thin protective layer = conductive coatings
Protection in damp and dirty environments
Each element is coated, with all plug-in contacts retaining full functionality. All visual components such as LEDs, MOST devices, light sensors, light barriers, laser technology, 7-segment displays, small displays retain full visual transparency. Particularly suitable for high-frequency circuits in the GHz range.
No impairment of the functions of the electronics or mechanics
High ageing resistance even under stress of temperature and sunlight.
Non-toxic ingredients - non-flammable.
Material: Fluoropolymers, silicones, polyolefins - also with UV tracer
Process: Dip coating for fluoropolymers. Otherwise spraying on many surfaces. Both methods have high process speed and high application safety.



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 Thin protective layer = quickly applied and versatile
Protection for moderate requirements
Complete or selective coating by spraying, jetting or dipping
Acrylic varnish: Good adhesion, LEDs remain visible, does not yellow. Different viscosities are available. Non-toxic versions are available.
Silicone varnish: Partially removable. Temperature resistant. Permanently flexible.
Urethane varnish: for high resistance.
UV-curing varnishes: Very fast drying. Solvent-free. Permanently elastic. Transparent, temperature change possible without problems

 

 

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Thick protective layer, potting = the shield among varnishes
Best protection against mechanical influences, shock, vibration and water.
Complete in housings, selective in moulds.
Suitable for outdoor and underwater circuits
Materials: Polyurethanes, epoxies, silicones (one and two components).