by Jim Hisert , Sigurd R. Wathne PE
The best way to test a flux is to conduct the test in the production line under actual working conditions. This can be impractical if too many materials are included in the evaluation process. There are, however, ways to understand the capabilities of a wide range of flux materials without scrapping a large amount of production parts and time. This article will outline a test procedure that can be used to initially compare fluxes with minimal time, capital expense, and equipment. The key data is the quality of a flux to promote wetting of various alloys on a variety of surface finishes. [1] This will be calculated as a change in solder diameter after reflow. Although solder spread is the numerical outcome of the testing, cleanability of water-soluble fluxes and post reflow residue of no-clean fluxes may become apparent to the technician involved in this testing. It is a good way to get a feel for a material set in a very short time.
Solder Melting, Solder Basics, solder alloy, solder, pb-free, Flux Cleaning, flux, BGA, ball attach
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Posted on 1 Jan 2009
by Adrian Low, Jim Hisert , Andy C. Mackie PhD
Although there are some unsubstantiated claims that the history of solder reaches back 7000 years (Ref. 1), it seems more likely that the first
gold-tin solders were used in jewelry in the Egyptian Early Dynastic Era, around 5000 years ago (Ref. 2).
Why is solder still the overwhelming choice for interconnects when high-tech alternatives abound? The answer is simple: Solder is the only electrically conductive
joining material that is so compatible with the metal surface it is joining to that it intermingles on the atomic level.
Solder Melting, solder alloy, solder, pb-free, Flux Cleaning, flux, BGA, ball attach
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Posted on 15 Oct 2009
