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January 2000

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Subject:
From:
Kenny Bloomquist <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 6 Jan 2000 12:46:39 -0800
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Paul,

You ask some very valid questions and that's why I started this thread.

In response to some of your questions:

>could you enlighten me please: why the spot-bond , and what is the
>detrimental effect occurring (?) with loose seat ?

Small PTH components can float and tip during wave solder.

>(upon loose cooling on crystalline formations ?)
>Always thought the joint is actually too robust (as those with cavities
>actually live longer),
>but if you say this kind of effort is worth it , than 'm missing something .

I don't think this is the issue unless you have a jerky machine that can
knock components around, but then you have a lot bigger problem than
stabilizing some components.

>And how do you spot-bond actually (hand?)?

Some do it by hand but we use an Asymtek X-X-Z machine along with some hand
application.

>Would a delayed heat (quartz tube just behind wave) postpone the solidus
>just long enough to freeze in peace ?

Again I don't believe this is the concern.

>What would be the validated/qualified difference with and without (the
>spot-bond)?

Perfection of the product with no misaligned components.

Just some thoughts, I sure others will have more.


Ken Bloomquist
Sr. Principal Process Engineer
PRIMEX Aerospace Company
P.O. Box 97009
Redmond, WA 98073-9709
http://www.primextech.com

Ph:   425-885-5000
FAX: 425-882-5786
[log in to unmask]

Northcon/2000, Chairman of the Board
http://www.northcon.org

Electronics Manufacturers Association (EMA), President
http://www.ema-wa.org

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