Dear Mr. Canner:

I am writing to you off-line about your posting on the leadfree forum
because I'm not sure I understand your point. I believe you are saying
that it is necessary to use 90/10 solder inside components because the
solder must withstand the high temperatures experienced during wave
soldering. I also conclude that you are suggesting a move away from wave
soldering would be logical because components passing through reflow
ovens experience lower temperatures. Am I (forgive the pun) warm?

Thanks for your time and best wishes,

Jim Smith
Cambridge Management Sciences, Inc.
4285 45th St. S.
St. Petersburg, FL 33711-4431
Tel: (727)866-6502 ext. 21
Fax: (727)867-7890
eMail: [log in to unmask]

James Canner wrote:
>
> The component manufacturers have been doing the most about this.  The
> problem is the board assembly people do not want to use the finesse of
> process but continue to use wave solder ( large lead losses) and other
> processes indiscriminately with no regard to the components.  The ceramic
> capacitor can withstand much higher temperatures, if care is taken to
> reduce the thermal shock..  Sn plating can also endure and be tin whisker
> free because the surface of the capacitor is stress free and contains no
> metals which promote the whisker growth.  The problem I have with the
> higher temperature is that there is no high temperature alternative for the
> 90Pb Sn alloys which we are required to use on leaded devices because of
> wave solder and reflow conditions. Why does the solder bump get such tender
> loving care when the IC cannot operate without the capacitor charge pump?
> The use of thermoplastic conductive adhesives with much lower relow
> tempertures seems to be the best direction to move in every case.
>
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