Abstract: Workpieces, such as printed circuit boards, are processed by passing the boards in contact with a standing wave of molten solder formed by circulating molten solder upwardly through a nozzle to overflow at least one edge thereof to form a standing wave which is accelerated by gravity so as normally to have an upper surface ballistically curved in the direction of flow. In accordance with the invention, the undersurface of the standing wave is supported to have a ballistic curvature, in the direction of flow, such that a major portion of the upper surface of the wave is substantially planar with the cross-sectional area of the wave varying, in the direction of flow, in a manner similar to the variation of the cross-sectional area of an unsupported wave following a ballistic curve in is trajectory.

Abstract: An ultrasonic soldering system is described. Electrical and electronic components are assembled in a circuit board with their leads extending through holes in the board. The components are temporarily held in position in the board by means of a solid, solder-compatible, stabilizer material having a melting point below that of solder, which material couples the board and leads to one another. The component leads are then trimmed to finish length, and after trimming, the components are soldered in place utilizing vibratory energy in a body of molten solder. The vibratory energy in the solder scrubs the board and leads removing oxides and allowing wetting, thus eliminating the need for application of fluxes and surface preparation prior to soldering. The stabilizing material is melted and displaced simultaneously with soldering.

Abstract: The invention relates to a soldering bath for fluxless soldering purposes, consisting of a vessel containing the molten solder or a channel carrying molten solder, with several sonotrodes passing through the base of said vessel or channel.