Siemens sinumerik 808d Programming And Operating Manual page 183

Explanation of the parameters
PO1 and DM1 (starting point and diameter)
These parameters are used to define the original starting point for the thread series. The
starting point determined by the cycle itself and approached at the beginning using G0 is
located by the run-in path before the programmed starting point (starting point A in the
diagram on the previous page).
PO2, DM2 and PO3, DM3 (intermediate point and diameter)
These parameters are used to define two intermediate points in the thread.
PO4 and DM4 (end point and diameter)
The original end point of the thread is programmed under parameters PO4 and DM4.
With an inside thread, DM1...DM4 corresponds to the tap hole diameter.
Interrelation between APP and ROP (run-in/run-out paths)
The starting point used in the cycle, however, is the starting point brought forward by the run-
in path APP, and, correspondingly, the end point is the programmed end point brought back
by the run-out path ROP.
In the transversal axis, the starting point defined by the cycle is always by 1 mm above the
programmed thread diameter. This lift-off plane is generated automatically within the control
system.
Interrelation between TDEP, FAL, NRC and NID (thread depth, finishing allowance, number
of roughing and idle passes)
The programmed finishing allowance acts paraxially and is subtracted from the specified
thread depth TDEP; the remainder is divided into roughing cuts. The cycle will calculate the
individual infeed depth automatically, depending on the VARI parameter. When the thread
depth is divided into infeeds with constant cutting cross-section, the cutting force will remain
constant over all roughing cuts. In this case, the infeed will be performed using different
values for the infeed depth.
Turning Part 2: Programming (Siemens instructions)
Programming and Operating Manual, 05/2012, 6FC5398-5DP10-0BA0
Cycles
2.5 Turning cycles
183