Industrial Crimp Quality Handbook
Doc No: TM-640160065
Release Date: 00-00-02
UNCONTROLLED COPY
Page 20 of 27
Revision: C
Revision Date: 12-23-09
Insulation
Not Visible
REJECT
Wire Not
Visible
REJECT
Window
ACCEPT
REJECT
Insulation
Pierced or
Crushed
ACCEPT
Insulation
Slightly
Damaged
SECTION 7
QUALITY CRIMPS
Quality is something that must be measured by some
set of criteria. Four major agencies give test criteria for
quality of solderless terminals. They are:
U.L. (Underwriters Laboratories)
CSA (Canadian Standard Association)
NEMA (National Electronic Manufacturers
Association)
Federal Government Spec - Mil-T-7928
In all of the above standards specific reference is made
to the following areas:
Copper or brass quality specifications
Tin-plating specs type and thickness
Smoothness of edges and lack of burrs
Firmness of fit between metal and insulation
Then there is a whole series of tests to be performed
on the crimp area after the crimp is made:
Tensile test
Dielectric withstand
Salt spray
Vibration
Heat rise
The most widely used field test for testing the quality of
the crimp is the pull test, or tensile test.
The two most widely used measurements are the U.L.
and Military Tensile values. See Section 8. Note that
the Military pull force is higher than the U.L.
7.1 Visual Inspection of
OPEN BARREL
Crimps
Insulation Not Damaged
1.
Crimp the insulation just enough (may have a
slight indentation to hold the wire in place). If
the insulation has been pierced or crushed, the
wires inside may have been damaged also.
2.
Be sure that the conductor insulation has not
been pierced or crushed by the crimp.
Insulation Support Crimp
1.
Be sure that the insulation barrel tabs are not
bent.
2.
Form the tabs properly.
3.
If one of the tabs is bent, the insulation crimp
will not be strong enough to provide the
needed stress relief.
Wire Visible
1.
Be sure that both the
wire and the insulation
are visible in the window.
2.
If only the insulation is
visible, you may have crimp insulation in the
conductor barrel.
3.
If only the bare wire is visible, you cannot assume
that the insulation has been properly crimped.
4.
If there is no insulation support crimp, be sure that
the length of the wire visible behind the conductor
crimp is not greater that the diameter of the
insulation. If the length of the wire visible exceeds
the diameter of the insulation, the terminal could
cause a short circuit.
Insulation
Tab Bent
REJECT
Metal Insulation
Tabs Formed
.
Wire
Is Held Snugly
ACCEPT
ACCEPT
Wire Visible
REJECT
Insulation
Diameter
Exceeds
Insulation Diameter
