Thread Undercuts (Cycle940) - Siemens SINUMERIK 840D sl Operating Manual

8.2.5

Thread undercuts (CYCLE940)

Function
You can use the "Thread undercut DIN" or "Thread undercut" cycle to program thread
undercuts to DIN 76 for workpieces with a metric ISO thread, or freely definable thread
undercuts.
Approach/retraction
1. The tool first moves to the starting point calculated internally in the cycle at rapid traverse.
2. The first cut is made at the machining feedrate, starting from the flank and traveling along
3. The tool moves to the next starting position at rapid traverse.
4. Steps 2 and 3 are repeated until the thread undercut is finished.
5. The tool moves back to the starting point at rapid traverse.
During finishing, the tool travels as far as cross-feed VX.
Procedure
Turning
Operating Manual, 02/2012, 6FC5398-8CP40-3BA0
the shape of the thread undercut as far as the safety distance.
1. The part program or ShopTurn program to be processed has been
created and you are in the editor.
2. Press the "Turning" softkey.
3. Press the "Undercut" softkey.
4. Press the "Thread undercut DIN" softkey.
The "Thread Undercut (DIN 76)" input window opens.
- OR -
Press the "Thread undercut" softkey.
The "Thread Undercut" input window opens.
Programming technology functions (cycles)
8.2 Rotate
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