TECHNET Archives

April 2007

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Bloomquist, Ken" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Bloomquist, Ken
Date:
Fri, 6 Apr 2007 07:29:16 -0700
Content-Type:
text/plain
Parts/Attachments:
text/plain (37 lines)
Good afternoon all,

I've go some assemblies that are not taking conformal coating in some
areas. The boards are reflowed and then selective wave soldered with a
pallet. They us a water sol flux and run it through an inline wash using
DI. We wash them in a batch washer using a mild saponifier prior to
coating. The boards are cleanliness tested in a ROSE tester and then
coated with polyurethane.

It is only on a few boards and it appears to almost be coming from the
via's. If we try to brush coat over it it still won't coat. If we clean
it with IPA then it coats just fine.

We've ruled out silicone and finger grease.

I have a couple of photos so you can see what it looks like. One is
black light showing the void areas. The other one is where we tried to
touch up the coating around a via and you can see how it pulled back.

http://www.ema-wa.com/DSCF0845ViaContamAreas.jpg 

http://www.ema-wa.com/DSCF0840_Via_Close-up_Y1_WL.JPG 

Thanks,

KennyB

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2