Siemens SINUMERIK 840D Programming Manual page 86

2
Drilling Cycles and Drilling Patterns
2.1 Drilling cycles
Description of parameters
See Subsection 2.1.2. (Drilling, Centering –
CYCLE81) for a description of parameters RTP,
RFP, SDIS, DP, DPR
DTB (dwell time)
You program the dwell time in seconds. It works in
parameter ENC depending on which technological
variant you selected.
SDR (direction of rotation for retraction)
The direction of rotation for retraction when tapping is
programmed in parameter SDR. For tapping with an
encoder, the direction of spindle travel can be reversed
automatically, for which SDR=0 is set.
SDAC (direction of rotation)
As the cycle can also be called modally (see Section
2.2), it requires a direction of rotation for tapping further
threads. This is programmed in parameter SDAC and
corresponds to the direction of rotation programmed
before the first call in the higher-level program. If
SDR=0, the value assigned to SDAC is of no
significance in the cycle and can be omitted from the
parameterization.
ENC (tapping)
If tapping is to be performed without encoder although
an encoder exists, parameter ENC must be assigned
the value 1.
However, if no encoder exists and the parameter is
assigned the value 0, it is ignored in the cycle.
• Tapping without encoder with input of the lead (SW 6.2 or higher):
From SW 6.2 you can calculate the correlation
between feed and speed via the programmed lead
within the cycle for tapping without encoder (G63
thread). The speed must be programmed before the
cycle is called.
You can specify the lead either via MPIT (metric
thread unit) or via PIT (thread lead as value) just as
for tapping without encoder.
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SINUMERIK 840D/840Di/810D Programming Guide Cycles (PGZ) – 11.02 Edition
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© Siemens AG, 2002. All rights reserved