Hughes Aircraft Company

Randall L Mays

Raymond L Turner

Billy L Montgomery

Apparatus and methods for fluxing with water-soluble flux. A circuit card assembly has its solderable surface exposed for fluxing. A spray nozzle atomizes the flux to provide a mist that wets the surface without creating flux droplets. A pump is coupled between the spray nozzle and a container which stores the flux for pumping flux and atomizing the flux to create the flux spray. The apparatus may be used as a stand alone fluxing station for use with a liquid wave solder or vapor solder system. Alternatively, the apparatus may be used as an integral part of a wave soldering system that replaces the conventional fluxing station. In this embodiment, the apparatus is located beneath the conveyor and a sensor is used to actuate the flux spray. A plurality of nozzles or pluralities of sets of nozzles may be employed to achieve proper wetting of the assembly. One fluxing and soldering method comprises providing a water-based soldering flux, and atomizing the flux to create a mist that is sufficient to wet the solderable surfaces of the assembly. The assembly is soldered within about ten minutes of the fluxing operation. If wave soldering is used, the conveyor speed is set at twice the speed for soldering with conventional RMA flux. The soldered assembly is cleaned within about fifteen minutes of soldering operation using a surfactant diluted in about forty gallons of deionized water and heated to between about 150 and 160 degrees Fahrenheit. Finally, the assembly is rinsed using deionized water.

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Fullerton, CA, United States of America

Randall L Mays