Collins,
Solder wetting can not be achieved to these plated through holes by hand
touched-up, including the use of RMA flux or Soldernew(machanical
abrasion). Note, water soluble flux(Alpha Metals WS362-25)was originally
used in the wave solder fluxing process.
Regards,
Frank Norman
Manufacturing Support Engineer
Raytheon, Space and Airborne Systems (SAS)
(805)879-2745
[log in to unmask]
Collins Graham <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
07/29/03 08:48 AM
Please respond to "TechNet E-Mail Forum."; Please respond to Collins
Graham
To: [log in to unmask]
cc:
Subject: Re: [TN] Lead Junction Temperature
Hi Bill
I'd lean toward re-use of an IC provided the moisture sensitivity rules
have been applied. Diodes and caps I'd worry about if they are SMT
version because I would worry about cracking them with the heat.
Through-hole versions - much more robust parts, I'd consider re-use.
Obviously it also depends on the abilities of your rework folks, but
I'd assume they are top notch given your industry.
regards,
Graham Collins
Process Engineer,
Northrop Grumman Canada Corporation
Halifax
(902) 873-2000 ext 6215
>>> [log in to unmask] 07/29/03 12:38PM >>>
Hello all,
Is there any data or study that I can use that shows what the internal
junction temperature of a leaded device is when removing a part with a
solder sucking operation. Is there any reason why an IC, diode, or cap
cannot be re-used when removed from a circuit board prior to test if
the
device was installed with incorrect polarity? I think that the PWB
serves as
a buffer when desoldering from the solder side and therefore the part
is
protected.
We are in the launch vehicle business. There are some that say a part
can
only be soldered once. So, a diode soldered into a board cannot be
removed
and re-soldered correctly even though no power has been applied. The
unsoldered part must be discarded and replaced with a new part.
Any ideas how this relates to surface mount?
I know that part re-use takes place all the time but the fact that
launch
vehicles are involved fosters a very conservative approach. Any
comments
from the high-rel, class 3 folks?
Thanks to all who can respond, I really appreciate it.
Bill Kasprzak
Moog Inc, Electronics Process Engineering
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