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September 1999

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Subject:
From:
Michael Fenner <[log in to unmask]>
Reply To:
Michael Fenner <[log in to unmask]>
Date:
Wed, 29 Sep 1999 08:37:03 +0100
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text/plain (54 lines)
Don't forget the cylinder gas will be cold so you will need to ask Rube to wind the feed
pipe around the solder pot a couple of times.

It is possible to get surprisingly low oxygen ppm using "Heath-Robinson" (Brit mad machine
inventor) contraptions and gas bottles. I take no credit for its invention but did once
use a bottle fed simple inverted lid device to feed N2 over PCBs in air reflow ovens. The
lid travelled down the conveyor sitting over the work and maintained O2 at around 20-50
ppm. The only problem was pulling the H O T hose back out after.

Mike Fenner

----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: 29 September 1999 00:34
Subject: [TN] Pre-Tinning Fine Pitch...


> Hi ya'll!
>
> Boy, I may have quite a task ahead of me. There's this assembly that has hit
> the floor that has just about every part (CQFP's and ceramic SOIC's) in the
> un-formed state, and we've got to form and trim, then Pre-tin the gold plated
> stuff. I've already got a call into Six Sigma to get a quote on doing this
> stuff for me, but it may turn-out that we won't have the time to deal with
> this build and sub-contracting the forming and trimming, and pre-tinning out
> (what's new?).
>
> But in case I have to pre-tin the CQFP's myself, are there any tips that
> anyone can share to help me get through this as painlessly as possible? These
> parts are 320-pin 25-mil pitch and still have the tie-bars attached. I've got
> a bottle of nitrogen and plan to "Rube-Goldberg" me an enclosure to blanket
> the pot with nitrogen over the tinning pot that I'll be using...I think
> that'll help to cut down on the bridging I'll see. I'm going to use an RMA
> flux as well...any other suggestions? PLEASE?
>
> Thanks!
>
> -Steve Gregory-

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