Apparatus for manufacturing printed circuits

Claim 1

Apparatus for producing a thin, evenly distributed protective solder coating over the entire conductive area of a printed circuit board comprising an enclosed compartment, an exhaust gas vent line from the interior of said compartment, a conveyor movable horizontally through the interior of said compartment and adapted to support a plurality of solder coated circuit boards with the conductive area exposed and positioned in a horizontal plane for movement along a substantially horizontal path through said compartment, power means for continuously moving said conveyor and supported boards along said path in a given direction, means for containing a volume of superheated fluid and maintaining it at a temperature exceeding 360* F. and substantially above the melting point of the solder applied to the circuit board, a plurality of spray nozzles arranged within said compartment along a line transversely of said path with the nozzles aligned to have the spray therefrom vertically inclined at an acute angle to and along the axis of said path in a direction opposite that of said conveyor motion, a conduit connecting said liquid containing means and said nozzles, and a pumping means associated with said conduit for pumping the 360* F. temperature exceeding fluid through said conduit to exit as a spray from said nozzles, whereby said heated liquid from the spray melts the solder coating and the impact thereof evenly distributes the melted solder into a smooth and level film covering the entire conductive area.