Hi, Pat,
HMP solder has a melting point about 100 degrees lower than your example
for electronics. Depends what you are soldering, but most components have
an upper temp limit for the dies around 230 deg C and a few go to 250 deg
C. Beyond that you risk internal damage.
In-service temperature excursions depend on the operating environment and
are limited by, and to, the rating of your components. Commercial parts are
rated between -20 deg C (at best) and +70 deg C. Industrial parts are rated
between -40 deg C and +85 deg C, while military parts are rated between -40
deg C and +125 deg C. Outside of these temperatures, the components may
work, but their specified performance is not guaranteed. They should not
see temperatures approaching soldering temperature in operation - they
definitely wouldn't survive for long at that.
Temperature settings for soldering should be 20 to 30 deg C above
liquidous, but watch out for the max case temperature of the components -
you may be getting pretty close to that with these settings. You will have
to tread a fine line between peak temperature and its duration to get the
boards to solder without damaging the component dies.
Good luck
Peter Duncan
"Diamond, Pat"
<PDiamond@WESTO To: [log in to unmask]
NAERO.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST
Sent by: Aero/ST Group)
TechNet Subject: [TN] Solder temperature question
<[log in to unmask]
G>
11/13/01 04:17
PM
Please respond
to "TechNet
E-Mail Forum."
/Dear all,
I'm looking for some advice on the threshold limits for solder
temperatures,
if for example, HMP solder is solidus/liquidus at say 296-301 deg C, what
is
the highest temperature excursion it can see in service before the
properties of the soldered connection are affected?
I heard somewhere that as a rule of thumb you should allow around 40 deg C
below the melting point of the solder being used.
Any help/advice that you can give would be appreciated.
regards,
Pat Diamond
Weston Aerospace
Farnborough
UK
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