Siemens SINUMERIK 840D Operating Manual page 321

Procedure
Parameters, G code program
PL Machining plane
Milling direction
RP Retraction plane
SC Safety clearance
F Feedrate
Parameters Description
∇ (roughing)
Machining 
∇∇∇ (finishing)

Machining direction:
Z0 → Z1

Machining from top to bottom
Z1 → Z0

Machining from bottom to top
Direction of rotation of the thread:
Right-hand thread

A right-hand thread is cut.
Left-hand thread

A left-hand thread is cut.
Position of the thread:
Internal thread

An internal thread is cut.
External thread

An external thread is cut.
NT Number of teeth per cutting edge
Single or multiple toothed milling inserts can be used. The motions required are
executed by the cycle internally, so that the tip of the bottom tooth on the milling insert
corresponds to the programmed end position when the thread end position is reached.
Depending on the cutting edge geometry of the milling insert, the retraction path must
be taken into account at the base of the workpiece.
Milling
Operating Manual, 03/2010, 6FC5398-7CP20-1BA0
1. The part program or ShopMill program to be processed has been
created and you are in the editor.
2. Press the "Milling" softkey.
3. Press the "Thread milling" softkey.
The "thread milling" input window opens.
mm
mm
mm/min
Programming technological functions (cycles)
Parameters, ShopMill program
T Tool name
D Cutting edge number
F Feedrate
S / V Spindle speed or constant
cutting rate
8.2 Milling
mm/min
mm/rev
rpm
m/min
Unit
321