TECHNET Archives

April 2005

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:
Lee parker <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Lee parker <[log in to unmask]>
Date:
Thu, 14 Apr 2005 12:40:20 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (68 lines)
Genny

If the problem with black pad is resolved, then the suppliers should be able to produce the problem at will and then demonstrate a corrective action that prevents the issue form occurring without any side effects. To the best of my knowledge this is not the case. 

What has taken place is that most suppliers are now recommending a gold thickness of two micro inches or less based on imperial data; there have been few reported cases of black pad when the gold is restricted to two micro inches or less. Unfortunately, no one has given me a convincing mechanism to explain the phenomena. Also as the gold thickness is reduced the probability of soldering issues is increased.

Best regards

Lee

  ----- Original Message ----- 
  From: Genny Gibbard<mailto:[log in to unmask]> 
  To: [log in to unmask]<mailto:[log in to unmask]> 
  Sent: Thursday, April 14, 2005 11:54 AM
  Subject: [TN] ENIG - no more problems?


  Just listened to a Lead Free presentation by one of our assembly materials
  suppliers.  They tested different pastes on different board finishes using a
  variety of different patterns, spacings, aperture sizes, etc,...
  By far and away, ENIG was the best finish for performance, for wetting,
  defects, voiding, ...
  The guy making the presentation said that he felt a lot of the initial
  concerns re ENIG - black pad being the biggest - have been resolved, and
  that they are no longer a concern, that they have determined what the cause
  of it is and eliminated it.  Anyone want to comment on that?  I'm not sure
  if he is correct, or just out of the loop.
  It was interesting as well:  ImmAg got a very bad rating from them in
  performance, even though many on this forum really praise that finish.  It
  exhibited dewetting (they printed solderpaste pads on an area with no
  soldermask, and the solder did not stay and spread where it was printed, it
  crept together with other pads into a big blob, like you might see a water
  drop do) and the amount of voiding was impressive!!
  About 4 years ago I joined this forum, and one of the reasons was because I
  was looking for info on ENIG.  We had done a prototype run of a couple of
  boards and they failed miserably.  They were never analyzed in depth, so it
  wasn't figured out what exactly caused the failure.  It was the excuse we
  needed to not choose this finish and some of the extra costs associated with
  it.
  However, with the Pbfree push now, I don't know if we should re-examine
  whether to use the finish.  For products where we needed a flat finish, we
  have gone to ImmSn, but we still use HASL wherever possible.

  Genny

  "Genius may have its limitations, but stupidity is not thus handicapped"
  Elbert Hubbard

  ---------------------------------------------------
  Technet Mail List provided as a service by IPC using LISTSERV 1.8e
  To unsubscribe, send a message to [log in to unmask]<mailto:[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]<mailto:[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]<mailto:[log in to unmask]>: SET Technet Digest
  Search the archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives>
  Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]> or 847-615-7100 ext.2815
  -----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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