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Multiple-Axis Machining | Running CAM programs
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
Please note the following for CAM programming
Adapting chord errors
Programming notes:
For finishing operations, do not set the chord error
in the CAM system to a value greater than 5 µm. In
Cycle 32, use an appropriate tolerance factor
T
of 1.3
to 5.
For roughing operations, the total of the chord error
and the tolerance
T
must be less than the defined
machining oversize. This avoids contour damage.
Adapt the chord error in the CAM program, depending on the
machining:
Roughing with preference for speed:
Use higher values for the chord error and the matching tolerance
value in Cycle 32. Both values depend on the oversize required
on the contour. If a special cycle is available on your machine,
use the roughing mode. In roughing mode the machine
generally moves with high jerk values and high accelerations
Normal tolerance in Cycle 32: Between 0.05 mm and
0.3 mm
Normal chord error in the CAM system: Between
0.004 mm and 0.030 mm
Finishing with preference for high accuracy:
Use smaller values for the chord error and an matching low
tolerance in Cycle 32 The data density must be high enough for
the control to detect transitions and corners exactly. If a special
cycle is available on your machine, use the finishing mode.
In finishing mode the machine generally moves with low jerk
values and low accelerations
Normal tolerance in Cycle 32: Between 0.002 mm and
0.006 mm
Normal chord error in the CAM system: Between
0.001 mm and 0.004 mm
Finishing with preference for high surface quality:
Use small values for the chord error and a matching larger
tolerance in Cycle 32 The control is then able to better smooth
the contour. If a special cycle is available on your machine, use
the finishing mode. In finishing mode the machine generally
moves with low jerk values and low accelerations
Normal tolerance in Cycle 32: Between 0.010 mm and
0.020 mm
Normal chord error in the CAM system: Smaller than
0.005 mm