Photo Image PCB Solder Resist, printed circuit board facts

Photo Imageable Solder Mask:-

With the ever increasing drive towards miniaturisation the traditional wet screened resists couldn't provide the definition required. Photo imageable inks are fast becoming the most widely used type of solder mask. This range of inks can be coated in a few different ways, curtain coating, screening, and electrostatic spraying. Curtain coating is done on a machine in which the boards are fed on a conveyor through a Niagara Falls of the ink. Electrostatic spraying is like normal pain spraying, but a high voltage charge exists between the spray gun and panel. In all cases the solder resist pattern is then transferred by aligning a photographic master and exposing using U.V. The panels then require developing in a mild alkali solution followed by high temperature baking. More expensive than the two pack epoxy inks but very high definition. Photo-Imageable S/R masks can have zero clearance, and are available in a large range of colours. Oddly enough these colours include black, which to date has always worked without incident. Quite how the UV successfully polymerizes through the black ink is a mystery, obviously it's time to re write rules and laws of science.




Peelable	The Process's