Siemens SINUMERIK 840D Operating Manual page 367

Parameters
G
Machining
Infeed (only for ∇ and ∇
+ ∇∇∇)
Thread
X0
Z0
Z1
LW
or
LW2
or
LW2 = LR
LR
H1
DP
or
Milling
Operating Manual, 03/2010, 6FC5398-7CP20-1BA0
Description
Change in thread pitch per revolution - (only for P = mm/rev or in/rev)
G = 0: The thread pitch P does not change.
G > 0: The thread pitch P increases by the value G per revolution.
G < 0: The thread pitch P decreases by the value G per revolution.
If the start and end pitch of the thread are known, the pitch change to be
programmed can be calculated as follows:
|P - P |
e 2 2
G = ----------------- [mm/rev2]
2 * Z
1
The meanings are as follows:
P : End pitch of thread [mm/rev]
e
P: Start pitch of thread [mm/rev]
Z : Thread length [mm]
1
A larger pitch results in a larger distance between the thread turns on the
workpiece.
∇ (roughing)

∇∇∇ (finishing)

∇ + ∇∇∇ (roughing and finishing)

Linear:

Infeed with constant cutting depth
Degressive:

Infeed with constant cutting cross-section
Internal thread

External thread

Reference point X from thread table ∅ (abs)
Reference point Z (abs)
End point of the thread (abs) or thread length (inc)
Incremental dimensions: The sign is also evaluated.
Thread advance (inc)
The starting point for the thread is the reference point (X0, Z0) brought forward by
the thread advance W. The thread advance can be used if you wish to begin the
individual cuts slightly earlier in order to also produce a precise start of thread.
Thread run-in (inc)
The thread run-in can be used if you cannot approach the thread from the side and
instead have to insert the tool into the material (e.g. lubrication groove on a shaft).
Thread run-in = thread run-out (inc)
Thread run-out (inc)
The thread run-out can be used if you wish to retract the tool obliquely at the end
of the thread (e.g. lubrication groove on a shaft).
Thread depth from thread table (inc)
Infeed slope as flank (inc) – (alternative to infeed slope as angle)
DP > 0: Infeed along the rear flank
DP < 0: Infeed along the front flank
Programming technological functions (cycles)
8.4 Turning - only for G code programs
Unit
mm
mm
mm
mm
mm
mm
mm
mm
367