Siemens SINUMERIK 840D Programming Manual page 72

2
Drilling Cycles and Drilling Patterns
2.1 Drilling cycles
Deep hole drilling with chip breaking (VARI=0):
• Approach of the reference plane brought forward
by the safety distance with G0
• Traverse to the first drilling depth with G1, the
feedrate for which is derived from the feedrate
defined with the program call which is subject to
parameter FRF (feedrate factor)
• Dwell time at final drilling depth (parameter DTB)
• Retraction by 1 mm from the current drilling depth
with G1 and the feedrate programmed in the
calling program (for chip breaking)
• Traverse to next drilling depth with G1 and the
programmed feedrate (sequence of motions is
continued until the final drilling depth is reached)
• Retraction to retraction plane with G0
Description of parameters
See Subsection 2.1.2. (Drilling, Centering – CYCLE81)
for a description of parameters RTP, RFP, SDIS, DP,
DPR
FDEP and FDPR (first drilling depth absolute or
relative)
The first drilling depth is programmed by either one of
these two parameters. The parameter FDPR has the
same effect in the cycle as parameter DPR. If the
values for the reference and retraction plane are
identical, the first drilling depth can be defined as a
relative value.
DAM (degression)
With deep holes, drilled in several steps, it is useful to
work with degressive values for the individual drilling
strokes (degression). This allows the swarf to get away
and there is no tool breakage.
In the parameter, either program an incremental
degression value in order to reduce the first drilling
depth step by step or a % value to act as a degression
factor.
DAM=0 no degression
DAM>0 degression as value
The current depth is derived in the cycle as follows:
2-72
Z
X
SINUMERIK 840D/840Di/810D Programming Guide Cycles (PGZ) – 11.02 Edition
2
03.96
11.02
G1
G0
G4
RTP
RFP+SDIS
RFP
FDEP
DP = RFP-DPR
© Siemens AG, 2002. All rights reserved