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Grid Encoders KGM |
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The contouring accuracy of machine tools is determined essentially
by motional deviations of the machine/drive/control system. The
development, acceptance testing, and regular inspection of machine
tools require not only the measurement of
positional deviation (e.g. with VM
182 comparator system from HEIDENHAIN, but also the measurement
of contouring deviations — especially at high traversing
speeds (dynamic accuracy). Circular
interpolation and free-form tests make it possible to draw
conclusions about both the condition of the machine and the
parameter settings of the control and drives.
The new KGM 182 Grid Encoder can
measure the dynamic accuracy of very small circles (i.e., with very
high axis acceleration) as well as any
curved path on a moving machine. It therefore provides
information on the positional and contouring performance of the
machine tool independently of machining influences.
The KGM 182
consists of a grid plate with a two-coordinate TITANID phase grating
on glass (4 µm signal period) embedded in a mounting base, and
a non-contact scanning head (1 VPP signal levels). The
mounting base is fixed to the machine table and the scanning head is
locked into the spindle. The grid plate of the KGM 182 has a measuring
range 230 mm in diameter. The system accuracy is ± 2 µm.
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KGM
181 |
KGM
182 |
Measuring
standard
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Signal period |
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Coefficient of
thermal expansion |
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Two-coordinate
TITANID phase grating on glass
(grid)
4 µm in both
directions |
atherm=
8 ppm/K |
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Measuring
range |
Dia.
140 mm |
Dia.
235 mm |
Accuracy
grade |
±
2 µm |
Evaluation
electronics* |
PC
counter card IK 220 |
Evaluation
software* |
ACCOM
for AT-compatible PCs |
Recommended
measuring steps |
1
µm, 0.1 µm, 0.01 µm |
*
included in delivery |
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