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Date: | Thu, 27 Jun 96 10:24:19 cst |
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Hi Eli -
We have soldered TO 220s to organic substrates (FR4, BT, etc.) with
very few problems. The reflow profile needs to be looked at for each
assembly so that you heat up the all of the components uniformly but
there is no "magic" in the process. I would not use any attachment
hardware unless your use environment (e.g. lots of vibration) requires
it - attachment hardware will increase your cost via assembly cycle
time and material costs.
Dave Hillman
Rockwell Collins
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Subject: TO220 reflow soldering
Author: [log in to unmask] at ccmgw1
Date: 6/26/96 11:37 PM
Dear Techneters
For years we have been reflow soldering TO 220 transistors to ceramic
substrates to provide good thermal dissipation . now we want to use FR4
boards . Our intention was to bend the TO220
leads and insert them in pths and reflow solder the body of the
transistor to the board on a suitable land and later wave solder the
leads . But I was told that in pcbs it is customary to use screws and
nuts or eylets instead of soldering .One explanation was that there is a
big thermal mismatch but no one seemed to know for sure .
What I would like to know if anyone has any experience in reflow
soldering TO220 s to pcbs and if anyone knows why it should not be
done.
thanking you
Eli Dallal
process engineer
Tadiran telecommunications
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