Photographic solder resist is an acrylic-epoxy coating with specific electrical, physical and chemical properties. Its primary function is to protect the conductors from possible short-circuits during the soldering process.
The solder resist printing process comprises the following phases: solder resist application, solder resist exposure, solder resist development, polimerisation.

The application process is carried out in-house using a coating machine, controlled several times a day to assure proper application thickness, followed by drying in a horizontal oven before printing. 

Printing is carried out with an automatic Bacher FAPS 600 HI exposure machine (with internal cameras for optimal centring) followed by the development line.

For  symbology screen-printing, frames are used made up of a metal frame and a suitably taut fabric (canvas).

Finally, printing the peelable solder resist serves to protect with a plastic coating those areas of the circuit that should not be soldered during wave soldering. Hence, apart from resistance to wave soldering, the coating must be easy to remove and must not overrun into other areas.