Charlie and Werner,
Our current solution is to fab a group of test boards all at the same
time, but using several different laminate materials from different
vendors. We will then run them through a temperature torture test at
the same time.
Example; 3 Tg 170 board materials processed together, then run through
wave together.
We will be watching for blistering and delaminating.
Phil
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Charlie McMahon
Sent: Tuesday, December 13, 2005 9:21 AM
To: [log in to unmask]
Subject: Re: [TN] Qualification of the Pb-free capable manufacturers
Hello Werner:
Your guidance is always prescient and timely. The suppliers you refer to
I
assume are laminate suppliers and I am curious as to their lack of
support
of your STII proposal.
As you clearly stated, the "instruction manuals" (my words) that come
with
the laminates as purchased by fabrication suppliers will have little use
in
terms of application questions for the end user based on the lead free
demands of processing.
Therefore, would it not be appropriate that, absent your STII proposal,
the
clients we supply with PWB first process coupons for each board design
at
assembly to ensure delamination does not occur BEFORE production. It
appears
that without an empirical benchmark as you properly suggest with the
index,
there is no other measurement of performance except the lawsuit to come
when
the assembled boards breakdown after assembly. I predict a blame the
fabricator and assembler future for us all.
I recall this being an issue when double sided SMT assembly came in
requiring multiple reflow temp. exposures to the PWA. Process soon
followed.
Shall there not be a procedure/process in place to do manually (read:
coupons) what the STII would do otherwise? At the very least it would
indicate parameters. As one who believes in the Deming co-operative
engineering principles and strong DFM at the fabricator, this strikes me
as
the one insurance policy that we need to consider. What is your view?
Charlie McMahon
McMahon Sales Company
P.O. Box 1024
Windham, New Hampshire 03087
Tel: 603-432-3111
Fax: 603-432-6854
Cell: 603-401-4646
e-mail: [log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard
Sent: Tuesday, December 13, 2005 8:57 AM
To: [log in to unmask]
Subject: Re: [TN] Qualification of the Pb-free capable manufacturers
Werner,
You are absolutely correct, as usual.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier
Sent: Monday, December 12, 2005 6:16 PM
To: [log in to unmask]
Subject: Re: [TN] Qualification of the Pb-free capable manufacturers
Hi Paul,
I certainly concur with you technical assessments--the reliability
bottleneck for LF-soldering will be in the PWB as well as in the
component areas, and less though with the solder joints, where most of
the efforts are concentrated.
There are people that understand these issues--there is you and PWB
Solutions, there is Hans Danielsson in Europe and I give workshops on
these issues. But you are correct, that the industry has not yet grasped
the importance of these issues. Thermal excursions to SnPb soldering
processes cost between 12 and 14% of the life of the PTHs/vias--going to
LF-solders and a 30C increase raises the cost to 18 to 20% of the
life--no wonder you saw what you reported.
The slash sheets for laminate/prepreg materials given in IPC-4101 are so
wide open in the ranges of properties that they are in fact useless. New
slash
sheets IPC-4101B/99, /101, /121, and /124 have been proposed for use
for
LF-soldering--again, the property ranges are much too wide to be useful
for any designer. I proposed a "Soldering Tempreature Impact Index
[STII]" for these slash sheets and was promplty shot down by the
committee consisting of lots of suppliers. The STII incorporates the 3
most important properties in this context, Tg, Td, and CTE.
Yes, there are people out there that understand the issues, the rest of
the industry will have to learn the hard way.
Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com
---------------------------------------------------
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
-----------------------------------------------------
---------------------------------------------------
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
-----------------------------------------------------
--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.371 / Virus Database: 267.13.13/199 - Release Date:
12/13/2005
---------------------------------------------------
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
-----------------------------------------------------
---------------------------------------------------
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
-----------------------------------------------------
|
