Abstract: A two-part, hand-held portable cleaning system provides the ability for washing and vacuum cleaning printing stencil screens and the like in-situ in an environmentally safe manner. The system includes a vacuum-assisted drip pan and an applicator brush with a specially designed low-pressure, solvent-dispensing nozzle. The drip pan is held beneath the stencil or screen while the applicator brush floods the area to be cleaned with solvent, thus dislodging the accumulated printing medium by the mechanical action of the brush. Much of the contaminated solvent flows through the stencil or screen into the drip pan below. Vacuum hoses attached to both the drip pan and the applicator brush remove the liquid solvent and any solvent vapor in the vicinity. A separation chamber is located in the air vacuum circuit between the blower and the hoses and is positioned above the reservoir connected thereto by a gravity-feed drain line.

Abstract: An apparatus and method for cleaning solder paste from stencils, screens, misprinted circuit boards, and tools associated with the manufacturing of surface mount technology circuit boards. The apparatus includes a holder assembly for holding the solder-laden objects during cleaning and rotatable spray arms connected with a chemical pump for spraying a transversely directed, cyclic waves of solvent onto the object's surfaces. The cleaning action of the spray arms permits use of the solvent at or below room temperature thereby substantially reducing evaporative loss of solvent, environmental injury resulting from such evaporative loss, and exposure of workers to solvent vapors. The apparatus includes filters for filtering heavy metal particles washed from the objects to contain the heavy metals for safe disposal. Safety mechanisms are included in the apparatus to prevent worker injury.