 
| Received: |
by ipc.org (Smail3.1.28.1 #2)
id m0uH54b-00008ZC; Wed, 8 May 96 03:58 CDT |
| Content-Type: |
text/plain; charset="US-ASCII" |
| Old-Return-Path: |
|
| Date: |
Wed, 08 May 96 10:59:42 +0100 |
| Precedence: |
list |
| Reply-To: |
|
| Resent-Sender: |
|
| Content-Transfer-Encoding: |
7bit |
| Status: |
O |
| X-Mailing-List: |
|
| TO: |
|
| X-Status: |
|
| Return-Path: |
<TechNet-request> |
| X-Loop: |
|
| Resent-From: |
|
| Resent-Message-ID: |
<"DqoJT1.0.6k8.e86an"@ipc> |
| Mime-Version: |
1.0 |
| Content-Description: |
<A:\IPC\FOOD.TXT> |
| Subject: |
|
| From: |
|
| Content-Id: |
<11_56_1_831567616> |
| Message-Id: |
<9605081801.AA0012@localhost> |
| X-Mailer: |
Ultimedia Mail/2 Lite, IBM T. J. Watson Research Center |
| From [log in to unmask] Wed May 15 18: |
03:31 1996 |
| Parts/Attachments: |
|
|
Thinking obout the environment and all, a solder paste that can be cleaned
after reflow using (DEMI)water is a beautiful thing. However, when i'm
thinking about using it, questions bubble up...
Water-washable fluxes in solder pastes are always? non-rosin (for example
organic acids). Because my fab produces many militairy PB's, this is
unaccceptable. Only R and RMA are conform the the good old MIL-STD-2000.
(Or you may only solder sealed devices etc. and still meet some conditions)
OK, flux activity of these paste are higher, but the modern OA flux-types are
comparable with RMA?
An other problem is that "Flux residue or foreign material" is a defect
(acc. to the 2000). Cleaning SMT, even with low residue/no clean flux becomes
very difficult that way. Especially when i consider that ionic contamination
test equipment for THT is not adequate for SMT. And when coating the PB's,
the less residue the better. Mixed THT/SMT products are also food for
thought.
Can someone help me see the light? Any statement, suggestion or experiences
using "aqua" pastes and cleaning/coating them after reflow FOR MILITAIRY USE
are welcome! (MIL-STD-2000 is still our guideline)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ivo de Rooij Process Engineer SMT/THT
Fokker Elmo BV (Fokker Aviation) [log in to unmask]
.
|
|
|
