Siemens SINUMERIK 840D sl Operating Manual page 248

Programming a cycle
4.7 Milling
Approach/retraction when milling external threads
1. Positioning on retraction plane with rapid traverse.
2. Approach of starting point of the approach circle in the current plane with rapid traverse.
3. Infeed to a starting point in the tool axis calculated internally in the controller with rapid
4. Approach motion to thread core diameter on an approach circle calculated internally in
5. Cut thread along a spiral path in clockwise or counterclockwise direction (depending on
6. Exit motion along a circular path in opposite rotational direction at programmed feedrate.
7. With a programmed number of threads per cutting edge NT > 2, the tool is fed in (offset)
8. If the plane infeed is less than the thread depth, points 3 to 7 are repeated until the thread
9. Retraction on the retraction plane in the tool axis with rapid traverse.
Thread sequence from bottom to top
For technological reasons, it may also be sensible to machine a thread from bottom to top. In
this case, the retraction plane will be behind the thread depth.
This machining is possible, but the depth specifications must be programmed as absolute
values and the retraction plane must be approached before calling the cycle or a position
after the retraction plane must be approached.
Procedure
248
traverse.
the controller with the programmed feedrate, taking into account the finishing allowance
and maximum plane infeed.
whether it is left-hand/right-hand thread, with NT ≥ 2 only one rotation, offset in Z
direction).
by the amount NT-1 in the Z direction. Points 4 to 7 are repeated until the programmed
thread depth is reached.
depth + programmed allowance is reached.
1. Select the part program to be edited in the "Program manager"
operating area.
2. Press the "Open" softkey or the "INPUT" key to edit the part program
in the editor.
3. Press the "Milling" softkey.
4. Press the "Thread milling" softkey.
The "Thread Milling" input window opens.
Operating Manual, 01/2008, 6FC5398-7AP10-0BA0
HMI sl Turning