TECHNET Archives

November 2008

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:
"Chafin, Ken G." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Chafin, Ken G.
Date:
Mon, 17 Nov 2008 09:26:46 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (186 lines)
Thanks to you and Brian Ellis for your suggestions.

We do business with a lab that can do SIR and IC testing.

The only change we are making to our process is a change from one no
clean flux (which seemed to cause adhesion problems with our
polyurethane coating) to Indium #9942.

We have completed 100 cycles of thermal shock per the IPC test noted
below and the conformal coating adhesion appears to not be a problem
with the Indium flux.

We are considering cycling the test samples in a chamber from -40 C to
+70 C in 95% humidity and then rechecking (IC lab testing probable to
verify no unacceptable ionic contamination levels on the boards.

Anyone have any views on the utility of this?

SIR testing only? 



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Joe Russeau
Sent: Wednesday, November 12, 2008 2:58 PM
To: [log in to unmask]
Subject: Re: [TN] Flux Qualification

Hi Ken,

If you are trying to look for electrochemical (ECM) failures as a result
of the flux, then you may wish to consider doing SIR testing per
IPC-TM-650, method 2.6.3.7.  The conditions used in this method (40 C /
93% RH with a 10 VDC bias and test for 7 days using continuous
monitoring) have been shown to be more stringent than using higher
temperatures with high humidity (i.e. 70 C / 95% RH), especially for low
solids fluxes (i.e. no cleans).  Part of the drawback of using higher
temperature / humidity test environments, is that you often cook off the
very residues you are trying to observe.  Work done by Dr. Chris Hunt of
NPL showed that lower temperatures with high humidity and lower biases
was better for evaluating the potential for ECM events due to flux
residues.

All that said, I would suggest evaluating the flux residues using the
above method with a test board that is designed for SIR and has
components to mimic modern assemblies.  The IPC-B-52 board comes to
mind.

I would highly recommend that you obtain the Gerbers for the board you
choose and have them made by your preferred supplier with your preferred
materials and surface finish.  This may cost you a bit more, but it
gives you an apples to apples comparison.

Secondly, it would be a good idea to compare the residues from your
current materials against the Indium material using ion chromatography.
This will give you some important additional data and provide a baseline
to compare to the SIR data and to the performance of your current paste
/ flux material.

Anyway, I hope this helps.

Best Regards,

Joe Russeau




----- Original Message -----
From: "Chafin, Ken G." <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, November 12, 2008 1:13 PM
Subject: [TN] Flux Qualification


We are trying to qualify a no-clean flux to be used in our wave solder
process.

The flux in question is Indium #9942.

After wave soldering our boards are conformal coated with polyurethane
coating Conathane CE-1164.

We have done some baking of a test sample at 70 degrees C and and have
tested per IPC-TM-650 2.6.7.1--thermal shock test.

This testing was done primarily to evaluate the adequacy of the adhesion
of the conformal coating.

We are interested in further evaluating this flux to determine if it
contributes to corrosion development or other undesirable effects.

We are considering "soaking" a sample in a chamber at 70 degrees C at
95% relative humidity for four or five days.

I am interested in any recommendations for further
testing--standards-related tests, nonstandards-related tests that may
reveal undesirable properties in the flux, etc.

Thanks



Kenneth Chafin
Quality Compliance Leader

  <file:///c:/signature/Email%20signature_files/image001.jpg>
1000 Technology Drive
Pittsburgh, PA 15219-3120
USA
Telephone: +1-412-688.2400 Ext [Ext]
Telefax: +1-412-688.2399
www.ansaldo-sts.com <http://www.ansaldo-sts.com/>



CONFIDENTIALITY
This message is strictly confidential. Its content and use is restricted
to the designated recipients. The use, copy, reproduction or transmittal
by any process or means without prior written notice of the Author or
Ansaldo STS / Union Switch & Signal Inc. office of the Legal Counsel is
strictly prohibited. If you have received this message in a transmission
error, please inform the sender immediately and destroy any copy, saved
files or print you have erroneously made.


PRIVACY:
Meeting the needs and expectations of our Customers and Employees has
always been our highest priority and that includes protecting their
privacy in compliance with local, state and federal laws and in
accordance to Ansaldo STS/Union Switch & Signal Inc. Privacy Code.


ENVIRONMENTAL NOTE:
IN SUPPORT OF OUR ENVIRONMENT, WE RECOMMEND NOT PRINTING EMAILS EXCEPT
WHEN ABSOLUTELY NECESSARY





---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------
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