Sample Program - Siemens SINUMERIK 840D Programming Manual

Milling Cycles
3
3.3 Thread cutting - CYCLE90

Sample program

(thread from bottom to top)
A thread must be cut starting from -20 up to 0 with a 3
mm pitch. The return plane is at 8.
N10 G17 X100 Y100 S300 M3 T1 D1 F1000
N20 Z8
N30 CYCLE90 (8,-20,0,-
60,0,46,40,3,800,3,0,50,50)
N40 M2
The hole must have at least a depth of -21.5 (half
pitch in excess).
Overshoot in the thread longitudinal direction
For thread milling, the travel-in and travel-out
movements occur along all three axes concerned.
This means that the travel-out movement includes a
further step in the vertical axis, beyond the
programmed thread depth.
The overshoot is calculated:
+
p 2 * WR RDIFF
∆z =
*
4 DIATH
∆z
Overshoot, internal
p Thread pitch
WR Tool radius
DIATH Outside diameter of the thread
RDIFF Radius difference for travel-out
For inside threads RDIFF = DIATH/2 - WR,
For outside threads RDIFF = DIATH/2 + WR.
3-110
SINUMERIK 840D/840Di/810D/FM-NC Programming Guide, Cycles (PGZ) - 04.00 Edition
03.96
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08.97
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