Richard Arnett

US Patent:

46845445, Aug 4, 1987

Filed:

Feb 19, 1986

Appl. No.:

6/830727

Inventors:

Richard K. Arnett - Kokomo IN

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H05K 322

US Classification:

427 96

Abstract:

Solder flux is applied to the face of a printed circuit board (24) or the like by flowing a foam (30) of liquid flux bubbles upwardly through the top of a chimney flue (10) and into contact with the board face which is top passed over the top of the flue. The size of bubbles adjacent the face of the board is controlled by placing a grid screen (26) within and immediately beneath the top of the flue. The openings (26a) in the grid screen allow passage therethrough of smaller bubbles (34) but prevent passage of larger bubbles (32). The force of the board face on the foam urges the larger bubbles downwardly into contact with the grid screen where the grid wires of the screen pierce and thereby break the larger bubbles into smaller bubbles which then rise to the face of the board.