Siemens SINUMERIK 840D sl Programming Manual page 421

Special features
● TRC selection:
● OFFN acts differently with TRACYL than it does without TRACYL. As, even without
● It is possible to change OFFN within a parts program. This could be used to shift the
● Guiding grooves:
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
TRC is not programmed in relation to the groove side, but relative to the programmed
groove center line. To prevent the tool traveling to the left of the groove side, G42 is
entered (instead of G41). You avoid this if in OFFN, the groove width is entered with a
negative sign.
TRACYL, OFFN is included when TRC is active, OFFN should be reset to zero after
TRAFOOF.
groove center line from the center (see diagram).
TRACYL does not create the same groove for guiding grooves as it would be with a tool
with the diameter producing the width of the groove. It is basically not possible to create
the same groove side geometry with a smaller cylindrical tool as it is with a larger one.
TRACYL minimizes the error. To avoid problems of accuracy, the tool radius should only
be slightly smaller than half the groove width.
Note
OFFN and TRC
With TRAFO_TYPE_n = 512, the value is effective under OFFN as an allowance for TRC.
With TRAFO_TYPE_n = 513, half the groove width is programmed in OFFN. The contour
is retracted with OFFN-TRC.
Transformations
6.8 Kinematic transformation
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