CNC Z32 - Programming Guide (LATHES)
After programming the G33 function, all subsequent movements are threading movements. The movements may
contain both linear and circular segments. During the execution of threading movements, the K pitch specifies the
displacement imposed to the tool, along the path, for each spindle revolution.
The end of threading movements must be indicated with a rapid movement (G0).
The profile to be threaded may be specified using the geometrical elements discussed before, i.e. taper elements,
connecting radiuses, etc.
Example:
Cylinder-taper threading
Warning: If the pitch along the Z axis must be maintained constant, it must be recomputed with the following
formula:
K = {pitch along Z} / cos(taper angle)
In the example, the pitch along Z is 2mm, the taper angle is 30 degrees, thus the K pitch in the taper area
is equal to:
K = 2/cos(30) = 2.309
Z
X
-40
50
-20
30°
OX1 OZ1
T2M6
G95 S400 M3
G0 X50 Z5
G33 Z-20 K2
Z-40 QF150 K2.309
G0 X80
M2
Threading motion synchronization:
It is important to consider that at the start of each threading movement, a segment in empty space is necessary to
synchronize the axes interested by the threading with the spindle movement.
Piniz
The threading movement must thus contain sufficient empty space to allow this motion synchronization.
The amount of empty space required depends on the kind of machining to be executed and by the dynamic of the
machine. For typical threadings, an empty space equal to three times the threading pitch may be considered.
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