Soldering bath with inert or reducing gas sparged oil cover layer - for high temp. soldering of electronics circuit boards, etc. with redn. of oxidn. and temp. accelerated degradation

摘要

Process for soldering of component assemblies (7) in an oil-covered solder bath (1) where the cover-layer oil is sparged with an inert or a reducing gas. Work (7) for soldering is carried in a frame (6) through a jet of solder (4) supplied from a pump (2) via a novel aperture (3), the excess solder falling back into the bath which is covered by an oil layer (9). Molten solder in this way being exposed to atmos. for approx. only 1-2 second. The acquired oxide during this period is negligible cpd. with the total bath capacity. The cover oil is also circulated, via a pump (25) and filter (15). At the base of the oil reservoir (16) a porous sintered pad (17) sparges a fine dispersion of gas bubbles through the filtered oil, tending to displace, or in the case of reducing gas, to react with, dissolving O2.