Abstract: An apparatus and process prepares surfaces on components, boards and the like for assembly and solder joining. Oxides and other coatings can be removed from surfaces to be soldered without having to solder coat surfaces prior to joining. A polymer and an activator combination is applied to the surfaces, the polymer being thermally de-polymerizable and the combination removing oxides from the surfaces. The surfaces are heated after application of the polymer and activator to de-polymerize the polymer. Solder is then applied to solder join the surfaces.

Abstract: A cover or shroud extends over a solder reservoir and has a slot for a solder wave to protrude therethrough. Gas is provided to blanket the solder wave and the shroud is positioned to reduce solder from contacting elements that are conveyed through the solder wave. The devise comprises a solder reservoir having at least one solder nozzle projected therefrom, a pump for forming a solder wave from the nozzle, a cover for covering at least a portion of the reservoir containing the solder wave, the cover having a longitudinal slot for the solder wave to pass therethrough and contain solder splatter caused by the solder wave falling into the solder reservoir. A gas supply provides gas under the cover and also provides a gas blanket over the solder wave, and a conveyor moves the element in a predetermined path over the cover ensuring at least a portion of the element passes through the solder wave.

Abstract: A solder nozzle to produce a smooth turbulent free solder wave has at least one air jet associated therewith to remove solder icicles and bridges that can form on the under surface of circuit boards and other elements. The circuit boards move in an upward inclined path in the direction of travel and after passing through the solder wave an air knife projects a non-oxidizing gas with sufficient force to remove excess solder. The soldering can occur in a non-oxidizing gas enclosure such as an inert gas, or a reducing gas, and vibrating the solder wave below ultrasonic frequencies can assist in the soldering.

Abstract: A tunnel enclosure has a fluid barrier curtain at an entry and an exit and provides an apparatus for soldering an element. The fluid barrier curtains permit an additive, such as a soldering aid or the like to be included with the fluid at the curtain. More than one zone permits different temperatures or gas atmospheres and elements are passed from zone to zone with fluid barrier curtains between. A process for soldering comprises conveying an element into an enclosed zone through an entry containing at least one fluid barrier curtain, with an additive added to fluid in the curtain, heating and soldering the element in the zone, and conveying the element from the enclosed zone through an exit containing at least one fluid barrier curtain.

Abstract: A method and apparatus for cleaning workpieces, particularly printed circuit boards upon which electrical components have been soldered, is capable of using a potentially flammable or explosive liquid cleaning solvent. In one embodiment, there are two immersion wash stages between which is a spray wash stage. The spray wash stage is formed as a closed chamber which is sealed when the immersion wash stages by liquid seals. To reduce the danger of fire or explosion in the spray wash stage an inert gas such as Nitrogen is introduced into the closed chamber. In another embodiment the spray nozzles are immersed in liquid solvent in a combined immersion/spray wash stage. This reduces atomization of the flammable solvent further reducing the danger of fire or explosion.