Fixed Point Approach; Fixed Point Approach: G75 - Siemens SINUMERIK 808D ADVANCED Programming And Operating Manual

Right-hand or left-hand thread
The sign of the thread lead determines the direction of spindle rotation:
Positive: right-hand (as with M3)
Negative: left-hand (as with M4)
Note
A complete thread tapping cycle with thread interpolation is provided with the standard cycle CYCLE84.
See the following illustration for tapping using G331/G332:
Axis velocity
For G331/G332, the velocity of the axis for the thread length results from the spindle speed and the thread lead. The
feedrate F is not relevant. It is, however, stored. However, the maximum axis velocity (rapid traverse) defined in the machine
data can not be exceeded. This will result in an alarm.
Programming example
metric thread 5,
lead as per table: 0.8 mm/rev., hole already
premachined:
N5 G54 G0 G90 X10 Y10 Z5
N10 SPOS=0
N20 G331 Z-25 K0.8 S600
N40 G332 Z5 K0.8
N50 G0 X30 Y30 Z20
N60 M30
8.6

Fixed point approach

8.6.1

Fixed point approach: G75

Functionality
By using G75, a fixed point on the machine, e.g. tool change point, can be approached. The position is stored permanently
in the machine data for all axes. A maximum of four fixed points can be defined for each axis.
No offset is effective. The speed of each axis is its rapid traverse.
G75 requires a separate block and is non-modal. The machine axis identifier must be programmed!
In the block after G75, the previous G command of the "Interpolation type" group (G0, G1,G2, ...) is active again.
82
; Approach starting point
; Spindle in position control
; Tapping, K positive = clockwise
of the spindle, end point Z=-25 mm
; Retraction
Programming and Operating Manual (Milling)
6FC5398-4DP10-0BA1, 01/2014