On 6 January, Edward wrote:

> I am interested in the reasoning in selecting point geometry used to
> contact gold over nickel pads on SMD boards. In some cases customers are
> requesting (high spring force, hardened steel pointed probes) and
> others are requesting round gold pleated moderate spring force probes. 

> The application is the same SMD pads with gold, what are the
> considerations in testing these pads.
> What are the different considerations for point geometry for different
> surfaces.

> I am most interested in why sharp hard points, rather than domed gold
> contacts, are used for gold pads?

> Is pad damage not an issue?  Is the problem simple related to dirty
> boards?

> Thanks in advance.

> ---------------------------------------------
> Edward G. Shea          |  Tel (909)981-1810
> Test Connections Inc.   |  Fax (909)981-3015
> Upland CA. 91786        |  [log in to unmask]
> ---------------------------------------------

Edward,

    You kinda' hit the nail on the head in a manner of speaking...it is kinda' 
because of "dirty Boards", but they're not really "dirty"... 

    The request for sharp points and high spring force are most likely from the 
people who are in a No-Clean process. The residues that remain from No-Clean 
fluxes are insulative, pretty hard (it's almost like a varnish), and aren't 
easily penetrated by "sissy" probes. 

    They need to be "manly" probes that are sharp, hard, and full of force in 
order to break the "hymen" of the residue...heh,heh,heh...(sorry 'bout the 
analogy, I know that was bad, but I just couldn't help myself. I went and stood 
in a corner for 10-minutes as punishment for my chauvinistic faux pax...) 

    I even think there's probes out now that actually rotate as the probe is 
depressed against it's spring in order to break through a no-clean residue.



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