Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Fri, 21 Apr 2000 09:04:04 -0700 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Iain:
There is a paper on this subject available on our website: A Comparison of
Methods for Attaching TCs to PCBs for Thermal Management, which was
presented at Nepcon last year. You can get it at:
http://www.kicthermal.com/library/index.html
Best regards,
Greg
----- Original Message -----
From: Iain Braddock <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, April 19, 2000 9:18 AM
Subject: [TN] Thermocouple attachment, how & why?
Cyber colleagues,
I would like to get others' views on the following subject.
When attempting to measure the thermal profile of a populated board
through a forced convection reflow oven what is considered the best form
of thermocouple attachment & why?
I believe there are four general methods of attachment.
1) T/c tip bonded to the lead/pad with something like a 2 pack epoxy
quick drying, covering the tip.
2) T/c tip touching lead/pad bedded onto a thermal compound paste
with it covering it.
3) T/c tip soldered to lead/pad.
4) T/c embedded through board directly adjacent to lead/pad with
compound covering tip.
Option 1 - Easy to apply and as the bonding agent isn't very thermally
conductive perhaps less likely to be influenced by the higher air
temperature in the chamber.
Option 2 - Easy to apply but perhaps influenced more with the air
temperature although being sunk by the board.
Option 3 - Difficult to achieve as the tip isn't very receptive to SnPb
solder.
Option 4 - Time consuming, destructive but perhaps less influenced than
the others with air temperature.
I appreciate that the temperature will also depend on where it is
attached on the board power plane etc.
Finally, but on a different but connected note, what would be the
consequence if some of the joints had only just managed to get a few
degrees above liquidus - reliability? Perhaps if you've read this one Mr
Engelmaier it may be up your street?
CIA Iain.
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################
|
|
|