Abstract: In accordance with one embodiment of the invention, solder masking material is pressurized by means of a fluid pump to approximately 250 psi and high speed valve is used to turn the flow on and off rapidly in order that small "shots" of fluid are propelled from a tip, through the air, to selected portions of a circuit board. The selected areas of the circuit board to be masked are situated oppositely from the tip , as by a XY positioning system for the tip and/or the circuit board. The drops of masking material, which form upon impinging of the shots onto the circuit board, may be varied in volume and diameter. Where needed, a continuous bead of masking material may be formed on the circuit board by spacing the dots sufficiently close together.

Abstract: In accordance with one embodiment of the invention, solder masking material is pressurized by means of a fluid pump to approximately 250 psi and a high speed valve is used to turn the flow on and off rapidly in order that small "shots" of fluid are propelled from a tip, through the air, to selected portions of a circuit board. The selected areas of the circuit board to be masked are situated oppositely from the tip, as by a XY positioning system for the tip and/or the circuit board. The drops of masking material, which form upon impinging of the shots onto the circuit board, may be varied in volume and diameter. Where needed, a continuous bead of masking material may be formed on the circuit board by spacing the dots sufficiently close together.