Abstract: First and second transparent metallized gauge plates (52 and 52') of solder-nonwettable, heat-resistant material, such as glass or quartz, each have a solder wave test pattern in the form of spaced parallel metal strips (56 and 56') formed thereon. The metal strips (56) on the first gauge plate (52) are of progressively increasing widths, with a narrowest strip located adjacent one edge of the plate and a widest strip located adjacent an opposite edge of the plate. The metal strips 56' on the second gauge plate (52') are of uniform widths. The first gauge plate (52) is engaged with a solder wave (34) to measure the activation level of a soldering flux (44) being introduced into the solder wave, and thereby to determine the capability of the solder wave to produce properly soldered printed circuit board assemblies (10).

Abstract: A solder-bearing lead (10) is provided with solder flow-control stops (20 and 22) on opposite surfaces of a contact finger (18) closely adjacent a flux-bearing solder preform (12) on the contact finger, to preclude flow of molten solder from the solder preform along the contact finger to a stem (26) of the lead in a soldering operation. The first solder flow-control stop (20) forces the molten solder to flow directly across sides of the contact finger (18) to a contact pad (14), where it is confined by the second solder flow-control stop (22) to form a soldered connection (24) in a reduced time period and without the necessity for any significant supplemental fluxing. Additional solder flow-control stops (38 and 40) also are formed on resilient spring clamping fingers (28) of the lead. The solder flow-control stops (20, 22, 38 and 40) are formed by oxidized portions of a phosphor bronze base metal from which portions of solder-wettable tin coatings (42 and 44) have been removed.

Abstract: In the wave soldering of terminals of an electrical device, such as a miniaturized printed circuit board assembly, the board is moved along a predetermined path so that it initially engages a first solder wave flowing counter to the direction of the board movement and subsequently engages a second solder wave flowing in the direction of board movement. The velocity of the solder in each of the solder waves is controlled independently by having separate independent pumping systems. Thus, the solder waves can be set at different independent velocities to achieve proper soldering of the terminals and associated conductor paths while reducing crossovers or bridges (i.e., shorts) between the terminals and the conductor paths as a result of the close spacing thereof.