TECHNET Archives

November 2001

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:
Alan Kreplick <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 8 Nov 2001 15:55:38 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (104 lines)
Nancy,

Check out the paper "A Comparison of Methods for Attaching TCs to PCBs for
Thermal Profiling" which is on KIC's web page:
http://www.kicthermal.com/press/articles.html      along with several other
good articles on reflow profiling.

We were using Kapton, but recently found that it was masking the
temperature by 5-10 C.  The methods of attachment, in order of accuracy and
repeatability that I've heard/read about are: temp-probes (or similar),
hi-temp solder, aluminum tape, and Kapton/glue at the bottom.

As for the questions:
1. where to put the thermocouple: board and/or paste as a minimum
2  typical or maximum profile: typical, but each assembly gets profiled.
3. specify typical condition: based on the solder paste suppliers
recommendations and the board design (layers, thickness, size/mix
components, etc).

Well, that's my two cents,

Al Kreplick
Sr. Mfg. Eng.
Teradyne, Inc.
978-370-1726


                                                                  
 (Embedded                                                        
 image moved   TechNet <[log in to unmask]>                          
 to file:      11/08/2001 03:25 PM                                
 pic08573.pcx)                                                    
                                                                  



Please respond to "TechNet E-Mail Forum." <[log in to unmask]>

To:   [log in to unmask]
cc:
Subject:  [TN] Reflow Process Profiling Methods


Hi Technet,

I need some help to identify the most common methods of thermocouple
placement when profiling reflow processes.  And while we are on the
subject, I would also like to collect information on targeting for typical
or recommended profiles versus absolute min/max boundaries.  Just three
easy multiple choice questions....

1. Where do you put the thermocouple?
   a. Embedded in a solder joint?
   b. On top surface of a component? (If so - how do you attach the TC to
   the part?)
   c. On surface of the PWB?
   d. In air?

2. Do you target reflow profiles to fit a "typical" curve or do you just
try to stay below a maximum?
   a. Target for typical?
   b. Stay below maximum?

3. How do you specify that Typical or Maximum condition?
   a. Peak Temperature and Maximum Time at that Peak?  (Please define
   conditions.)
   b. Total time above a fixed value (usually 183°C or 200°C)? (Please
   define conditions.)
   c. Solder Paste Alloy composition for above values?  (If you are running
   both SnPb and Pb-free, please reply for both)

If any of you would like to share soft copies of actual time/temp profiles
that you use for targeting or specifying an acceptable range of reflow,
please email to me off-line.

Thanks in advance for your help.
Nancy Reynolds
KEMET Electronics
---------------------------------------------------------------------------------

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