Siemens SINUMERIK 840D sl Operating Manual page 436

Programming technological functions (cycles)
8.4 Turning - only for G code programs
Parameter
G
Machining
Infeed (only for ∇ and ∇
+ ∇∇∇)
Thread
X0
Z0
X1 or
X1α
Z1
LW
or
LW2
or
LW2 = LR
436
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/rev
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 ∅ (abs, always diameter)
Reference point Z (abs)
End point X ∅ (abs) or end point in relation to X0 (inc) or
Thread taper
Incremental dimensions: The sign is also evaluated.
End point Z (abs) or end point in relation to Z0 (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)
]
2
Operating Manual, 03/2013, 6FC5398-7CP40-3BA1
Unit
mm/rev
2
mm
mm
mm or
degrees
mm
mm
mm
mm
Milling