Programming instructions

4-22
Motion Blocks NC Programming 17VRS
DOK-MTC200-NC**PRO*V17-ANW1-EN-P
Helical Interpolation
Helical interpolation is a combination of circular and linear interpolation
which is used to produce a spiraling tool path. The circular interpolation
takes place in the selected plane (G17, G18, G19) while linear interpola-
tion is simultaneously occurring in a third axis which is perpendicular to
the plane of circular interpolation.
25
50
50
-50
Z
Y
X
Fig. 4-29: Helical interpolation
With helical interpolation an arc and a straight line erected perpendicular
to the end point of the arc are both programmed in the same NC-block.
The axis feeds are coordinated in such a way that the tool describes a
helix which has a constant pitch.
No more than one coil (corresponding to a full circle) can be programmed
in an NC-block. A number of coils in sequence can only be produced by
programming a corresponding number of individual coils.
The programmed feedrate (F-value) relates to the actual tool path.
All other conditions are the same as in circular interpolation.
Example Helical interpolation in the X-Y plane with G90
20
40
60
80
100
20 40 60 80 100
X
Y
20
40
60
80
100
X
Z
-10010
[P1]
[P2]
[P3]
[P4]
[P1]
[P4]
KM
I=62.5
J=30
Fig. 4-30: Helical interpolation with G90