HEIDENHAIN TNC 620 User Manual page 472

12
Multiple axismachining
12.6 Running CAM programs
Please note the following for CAM programming
Adapting chord errors
When defining finishing operations, make sure
that the chord error defined in the CAM system is
not set to greater than 5 µm. In Cycle 32, use the
appropriate tolerance factor T of 1.3 to 5.
When defining roughing operations, make sure that
the sum of the chord error and the tolerance from
Cycle 32 is less than the defined machining oversize.
This ensures that no contour gouging will occur.
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 appropriate
tolerance 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 appropriately low
tolerance in Cycle 32 The data density must be high enough for
the TNC 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 an appropriately larger
tolerance in Cycle 32 The TNC then smooths the contour more
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 0.010 mm and
0.020 mm
Normal chord error in the CAM system: Smaller than
0.005 mm
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HEIDENHAIN | TNC 620 | ISO Programming User's Manual | 9/2016