CNC Z32 - Programming Guide (LATHES)
Helical interpolation (G12 – G13)
The function
G12
allow the execution of helical interpolations.
The function
G13
disables this mode.
The position programmed for the third axis is reached at end movement, together with the two axes of the plane.
The velocity when G12 is active is the programmed F value.
G12 can be activated also if the radius correction is active (G41 or G42 active): it thus allow the motion of the third
axis, always coordinated with that of the first two.
G12 may remain active, in radius correction mode, also in shortened or deleted segments.
Warning: If a segment shortened or deleted due to the radius correction, contains a movement on
the third axis, this movement will be completely executed together with the next valid movement.
Because the function G12 poses some limitations (slope, radius correction, etc.) it is a good programming practice
to program it only when necessary and disable it (G13) when not.
The helical interpolation may be useful in case of machinings with polar axes.
For example, if the polar axes are V and W, it is possible to execute a circle on the VW plane, while moving at the
same time the depth axis Z.
Example:
G12
G3 V..W..I..J..Z..
G13
It is not possible to program an helicoids more than one complete turn in a single block. To program more than one
turn, a repeating cycle must be used.
22