Siemens sinumerik 808d Programming And Operating Manual page 168

Cycles
2.5 Turning cycles
DT and DAM (dwell time and path length)
These parameters can be used to achieve an interruption of the individual roughing steps
after certain distances traversed in order to carry out chip breaking. These parameters are
only relevant for roughing. The parameter DAM is used to define the maximum distance after
which chip breaking is to be carried out. In DT, an appropriate dwell time (in seconds) can be
programmed which is carried out at each of the cut interruption points. If no distance is
specified for the cut interruption (DAM=0), uninterrupted roughing steps without dwell times
are created.
_VRT (lift-off distance)
Parameter _VRT can be used to program the amount by which the tool is retracted in both
axes when roughing.
For _VRT=0 (parameter not programmed), the tool will retract by 1 mm.
Contour definition
The contour must contain at least 3 blocks with motions in the two axes of the machining
plane.
If the contour program is shorter, the cycle is aborted after the alarms 10933 "Number of
contour blocks contained in the contour program not sufficient" and 61606 "Error in contour
preparation" have been output.
Relief cut elements can be connected directly one after the other. Blocks without motions in
the plane can be written without restrictions.
In the cycle, all traversing blocks are prepared for the first two axes of the current plane
since only these are involved in the cutting process. The contour program may contain any
motions programmed for other axes; their distances to be traversed, however, will not come
into effect during the whole cycle.
Only straight line and circle programming with G0, G1, G2 and G3 are permitted as the
geometry in the contour. Furthermore, it is also possible to program the commands for
rounding and chamfer. If any other motion commands are programmed in the contour, the
cycle is aborted with the alarm 10930 "Illegal type of interpolation in the stock removal
contour".
168
Turning Part 2: Programming (Siemens instructions)
Programming and Operating Manual, 05/2012, 6FC5398-5DP10-0BA0