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January 2000

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From:
Eric Kalgren <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 28 Jan 2000 13:44:23 -0700
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Once again I supplicate myself before the altar of TechNet.....

We are seeing dull/grainy looking solder joints coming off the wave solder machine (Electrovert EconoPak+).
These are high-rel, high mix PCAs that are required to conform to the old NHB5300.  Specifically the bit about having "bright and shiny" solder joints.

I am currently profiling the PCA to have an avg topside temp of 250 deg F when it hits the start of the solder wave.  
I suspect, based on my readings of Klein-Wassink that the joints are cooling too slowly (some of these PCAs have huge ground planes covering the entire top and bottom side).  That and the fact that the majority of the dull-looking joints are on heavy components?

My questions:
1)  Should I be profiling to a lower temp?

2)  Does anyone have any pet methods for helping to cool the joints more quickly?

We are working on getting the spec relaxed, but I think that I should be able to hit any spec with the correct profile.

Humbly, 


Eric Kalgren
BFGoodrich Aerospace
Data Systems Division
[log in to unmask]
(505) 938-5139

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