The Impact of LV 214-4 – The
German Automotive OEM
Connector Test Specification
It goes without saying that every manufacturer
wants to ensure they are producing a quality
product. Standards and specifications from
various organizations provide a guideline
from which manufacturers can measure
different areas of quality, while also providing
the end user with the reassurance that they
are purchasing a trustworthy, long-lasting
product. Within the wire processing industry
there are many standards that manufacturers
may choose or be required to adhere to. These
standards and specifications are constantly
evolving and increasing in detail, especially as
monitoring technology improves.
What is LV 214-4?
LV 214-4 is an automotive standard that was
developed by representatives of the German car
manufacturers Audi AG, BMW AG, Daimler AG,
Porsche AG and Volkswagen AG. The standard
outlines terminal requirements specifically for the
automotive industry. The standard addresses the
ability of terminals to be effectively evaluated by
crimp force monitors. To be used in an automotive
wire harness, terminal must exhibit certain crimp
force characteristics so that typical crimp force
monitors can effectively detect critical error modes.
Though it is currently in draft form and many
points are still largely theoretical, the standard has
been in progress for many years.
LV 214-4 defines what an empty crimp is;
something that is not clear to all. In a good crimp
the conductor crimp is filled with all conductor
strands and the insulation crimp with all
undamaged insulation material. Crimp parameters
are at the nominal values as specified by the
manufacturer. An empty crimp has a full insulation
crimp, but the conductor crimp is empty.
For many years, crimp force monitors have
analyzed the total area under the crimp curve.
However, LV 214-4 defines four area segments;
one for good crimps and one for each error mode,
specifically, empty crimp, missing strands and
insulation-in-the-crimp. The good crimp area is
the area between the good crimp curve and the
empty crimp curve. Similarly, the missing strand
area is the area between the missing strand curve
and the empty crimp curve. Alternatively, the area
for insulation-in-the-crimp is the area between
the insulation-in-the-crimp and the good crimp
curves. Differences in each of these areas must be
detectable for the corresponding error mode.
The LV looks closely at the “roll-in” portion of the
crimp. The roll-in area is the beginning of a crimp
force curve where the terminal wings begin to roll
in and close around the wire. Most monitors ignore
this portion because forces are usually inconsistent
and this part of the crimp process is not very
important. However, LV 214-4 analyzes relative
deviation and defines the positions X0 and X1.
Concepts: Old and New
The standard focuses on relative deviation of force
curves and headroom, both common concepts
with regard to crimp force monitoring. Relative
deviation is the variation of peak force expressed
as a percentage. Headroom is the difference
between the peak forces of the average good
crimp and empty crimp curves, also expressed as a
percentage.
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X0 is generally where the good crimp and the
insulation-in-the-crimp curves begin to diverge.
X1 is generally where the good crimp and empty
crimp curves begin to diverge. The LV provides a
formula to determine specific locations for X0 and
X1.