Information

A STEP AHEAD
DEFINITION
Crimping may be defined as the act of joining a conductor to
a pin or socket contact using a mechanical tool to compress
and displace metal. In a good crimp joint, there is a mutual
flow of metal, causing a symmetrical distortion of wire
strands and contact material. Such a joint is similar to a cold
weld. Mechanical strength and good electrical conductivity
are established.
Because of the new environments to which electrical
connectors are subjected, there has been a drastic change
in thinking relative to the use of precision crimp joints in
preference to solder.
CRIMPING CONFIGURATIONS
Stamped contacts use a folded type of
crimp (Fig. 1). Solid contacts use 2, 4, or
8 indents (Fig. 2). The wire strands and the
contact material are formed together in a
solid mass with reduction of area of the
wire strands. A minimum of voids exists.
CRIMPING CHARACTERISTICS
Connectors utilizing either style of Deutsch
crimped contacts permit the removal of
these contacts several times. Modification,
circuit changes, or replacement of contacts
may be made with the same quality
assurance as in production line assembly.
Crimping may be accomplished either with
hand tools, power tools or automated
power tools.
CRIMPED CONTACTS
Mechanically crimping contacts is now the
dominant wire termination method, for
some very good reasons:
1) Since no wet process is involved,
corrosion is not a problem. No adhesives,
fluxes or additives are used.
2) Strength, accuracy and over-all reliability
of a crimped contact are controlled by
the crimp tool, not the operator. The
field tools (except #4 solid style) release
the contact only after the full crimping
cycle is completed. The tools are relatively
inexpensive.
3) With smaller wire, the crimp is as strong
as the wire itself.
4) The joint can be inspected visually.
Viewing the wire through an inspection
hole in the contact makes inspection quick,
Common Contact System Technical Manual
STAMPED & FORMED STYLE
CROSS-SECTION ACROSS AXIS
FIGURE 1
SOLID STYLE
INDENTER CRIMP
CROSS SECTION ACROSS AXIS
FIGURE 2
easy and sure, both by the operator and by the inspector.
5) The crimping tool is universal, it accepts both pins and
sockets of many types.
6) Plating thickness is not restricted, as in solder joints, so better
corrosion resistance and contact reliability are achievable.
7) Crimping can be done anywhere even in the field, without
special preparation. Terminations are replaced or modified in
the field exactly as in the shop, using the same tools and the
same techniques, and with the same ease of operation and
certainty of results.
8) Total installed and maintenance costs
are lower since joining is quick and easy.
Crimp Tensile Test
The following information is provided as
an aid to manufacturing facilities that
terminate Deutsch crimp type contacts.
The term “typical” is used to illustrate
expected tensile strength results when
crimp tooling is in good working order
and properly calibrated. The term
“minimum” is used to illustrate a point
at which tooling is suspected of having
excessive wear, insufficient air pressure,
bad calibration, etc. Minimum does not
imply that the crimp is unacceptable, only
that an adjustment should be made.
The manner in which the tensile test is
performed is important in order to attain
valid test results. An axial load should be
applied at a rate of 1.0 in./min starting
from zero pounds until there is wire/
contact separations or wire breaking. Care
should be taken to avoid clamping on the
crimp barrel.
CRIMP TENSILE STRENGTH
(STAMPED CONTACTS)
#20 SIZE 10-20 lbs.
#16 SIZE 15-25 lbs.
#12 SIZE 70 lbs.
(SOLID CONTACTS)
#20 SIZE 20 AWG 20 lbs.
#16 SIZE 16 AWG 20-70 lbs.
#12 SIZE 12 AWG 70-75 lbs.
# 8 SIZE 8 AWG 90-125lbs.
# 4 SIZE 6 AWG 300 lbs.
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