MOVABLE SELECTIVE DEBRIDGING APPARATUS AND METHOD OF DEBRIDGING SOLDERED JOINTS ON PRINTED CIRCUIT BOARDS USING SAME

• Main Authors: LARRABEE, ALLAN, LANCE, NORTON, JOHN, WILLEMEN, LAMBERTUS, PETRUS, CHRISTINUS
• Format: Patent
• Language: English; French; German
• Published: 18.09.2002
• Edition: 7
• Subjects: CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MACHINE TOOLS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; PRINTED CIRCUITS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

A debridging tool incorporated into an automated wave soldering system adjacent to and after a wave soldering station removes bridges and/or excess solder formed during the wave soldering process by emitting, at a desired temperature which can be set using a heater and one or more thermo measuring devices, a pressurized stream of air, inert gas or other fluid only under selected areas of a printed circuit board, including a flexible circuit. The tool comprises a movable nozzle from which the stream is emitted and a means for transporting the nozzle under the printed circuit board. The tool targets only those areas of the board where bridges or excess solder repeatedly form during the soldering process without disturbing solder joints where no bridges or excess solder form. Since the debridging tool is positioned close to the wave soldering station, the latent heat from the soldering process remains in the printed circuit board, and the gas mass is relatively small, the pressurized stream may be kept below the temperature of molten solder. An inert environment around the selective debridging tool and the wave soldering station may be used to reduce the oxidation of the solder and reduce the formation of dross in the solder pot. The main soldering tower of the wave soldering station may have a removable insert with a non-round roller for generating a turbulent wave in the main soldering tower when the insert is installed.