A crimp is an engineered connection, just like a solder joint. A properly
made crimp connection is gas-tight and is not improved by soldering. The
part about properly made bears repeated again and again, else it may not be
gas-tight or the materials may be overstressed. This means that the wire
must be of the appropriate cross-sectional area, material and stranding for
the particular terminal. The wire insulation, if the terminal has an
insulation crimp section, must have a diameter in the acceptable range and
be of a compatible material. Especially important, the crimp die must be
specifically designed for the crimp terminal and wire combination. The
crimper/applicator/die combination must also operate to acceptable
tolerances as determined by the manufacturer. After use, adjustments are
sometimes needed and parts eventually need replacement.
Just as in soldering, if your process is appropriate and you control it, the
results are very, very repeatable. In fact, this is far easier to control
than soldering, as there are fewer variables and regular preventive
maintenance takes care of most problems. If you use a reasonable amount of
connectors from a particular manufacturer, they are often willing to come in
a couple of times a year to check over your tooling.
As others have mentioned, soldering stranded wire creates a stress
concentration point where the wire will usually break later. Wire
insulation is melted during soldering, which loosens up the insulation crimp
and changes the mechanical properties of the insulation. Flux entrapment is
another issue I hadn't thought of and Doug's explanation was educational as
to how this can bite you. For my money, a good mechanical crimp is more
trouble-free than crimping plus soldering.
Regards,
Seth Goodman
Goodman Associates, LLC
tel 608.833.9933
fax 608.833.9966
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Carl VanWormer
Sent: Wednesday, March 13, 2002 1:35 PM
To: [log in to unmask]
Subject: [TN] Soldering crimp connectors
We have a customer who insists that we solder our crimp connectors (after
crimping). He has had corrosion problems and is convinced that this is the
best solution. Is this a good thing? Are there any downsides we should
point out to help educate him?
Carl Van Wormer
Cipher Systems
1815 NW 169th Place, Suite 5010
Beaverton, OR 97006
Phone (503)-617-7447 Fax (503)-617-6550
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