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2.8.3 Work index
The work index is a dimensionless value that indicates the relative position of a specified section of the crimp
curve while the wire and terminal combination is being compressed.
V
alues from “Learn” crimp
s that are
“Accepted as good”
are collected to create a work index history. This is
used to calculate a mean value and standard deviation. These values are then used to establish a range of
good work index values.
Work index is a process monitoring analysis method. Analysis of its history can reveal how the crimping
process changes over time.
2.8.4 Peak force
The peak force is a maximum force reading (minus the idle force reading) that occurs during the crimp. It is a
relative and dimensionless value.
Values from
“Learn” crimps that are “Accepted as good” are collected to create a
peak force history. This is
used to calculate a mean value and standard deviation. These values are used to establish a range of good
peak force values.
Peak Force is a process monitoring analysis method. Analysis of its history can reveal how the crimping
process changes over time.
2.8.5 Point-to-point (P2P) analysis
A series of points are established along the crimp curve in the P2P analysis. During the “Learn” process the
CQM II computes means and standard deviations for each point and updates the mean and standard deviation
for each point with every good crimp within an acceptable update range. During Production each point is
compared to its upper and lower control limits, and if no points are out of their limits the analysis method
considers the crimp to be a PASS crimp. A sensitivity value determines the amount of standard deviations
allowed at each point. There is also a Fixed Upper and Lower control limits that get established by the first 30
PASS Crimps. Each point is checked both the fixed and non-fixed upper and lower control limits to determine if
the crimp is good.
2.8.6 Fast Fourier transform (FFT) analysis
The FFT analysis method converts the force profile into its component frequencies. It computes mean and
standard deviation for each of the lowest 32 frequencies from the Learn crimps and updates the mean and
standard deviation with each good crimp. The FFT display tab shows a graph of the tolerance limits and the
previous crimp
’s
computed frequency amplitudes. The tolerance limits are determined by the sensitivity
selected by the user (default is 2.0) multiplied by the computed standard deviations for each frequency.
If more than five frequencies fall outside the tolerance limits, the crimp status is FAIL.
Otherwise, the crimp status is PASS.
2.8.7 Force Only Mode
In certain custom machine applications, the CQM II can operate with a force sensor only and no position
sensor. A trigger sensor is used to signal the crimp event. In this mode of operation, only the Peak Force and
FFT analysis methods are available. For the FFT analysis, additional parameters can be selected in the Learn
mode (see section 0)
