TECHNET Archives

April 2001

TechNet@IPC.ORG

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

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

Print Reply
Content-Type:
text/plain; charset="iso-8859-1"
Sender:
Subject:
From:
"Campbell, William (wcampbel)" <[log in to unmask]>
Date:
Tue, 10 Apr 2001 16:27:28 -0400
MIME-Version:
1.0
X-To:
Bev Christian <[log in to unmask]>
Reply-To:
"TechNet E-Mail Forum." <[log in to unmask]>, "Campbell, William (wcampbel)" <[log in to unmask]>
Parts/Attachments:
text/plain (90 lines)
Bev-  try this:

http://www.residues.com/libraries1.htm

Also, xray usually won't show a short under a ceramic cap because of the
metalized layers.  By time you shoot through the cap, you've also shot
through the "short".  Best way to check for encapsulation is through
destructive analysis.  Also, removing the cap with heat will generally
destroy evidence underneath.

-----Original Message-----
From: Bev Christian [mailto:[log in to unmask]]
Sent: Tuesday, April 10, 2001 4:07 PM
To: [log in to unmask]
Subject: Re: [TN] Caps shorting on bottomside after wave...


Doug,
I tried through both Netscape and Explorer and I received messages about
"page not found".  Is it just me or CSL?

regards,
Bev

-----Original Message-----
From: Douglas Pauls [mailto:[log in to unmask]]
Sent: April 10, 2001 3:42 PM
To: [log in to unmask]
Subject: Re: [TN] Caps shorting on bottomside after wave...


Steve,
I have seen this problem before.  What is likely happening is that you are
curing the glue too fast.  The outer layer of the coating skins over,
entrapping volatiles.  They then blow out, leaving a pathway between the
pads.  This pathway can fill with flux, and the solder naturally follows,
creating a short.  I wrote about it in two Process Rx columns in December
98 (Microcanyons), and a follow up column in July 99 (Become One With the
Glue).  And yes, there was a fair amount of drinking going on during title
selection.  I can send you those articles if you are interested.  They also
appear on CSL's website, www.residues.com/library.

The client did are large designed experiment looking at single dot and
double dot application, and different glue curing rates.  They found that
by following the manufacturers recommended glue cure profile, they got the
best adhesion (imagine that, following directions actually works).

Doug Pauls
Rockwell Collins

----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----

----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------

ATOM RSS1 RSS2