User's Manual TNC 360 (from 259 900-11) - heidenhain

5 Programming Tool Movements
5.5 Path Contours – Polar Coordinates
Helical interpolation
TNC 360
A helix is the combination of a circular movement in
a main plane and a linear movement perpendicular
to the plane.
A helix is programmed only in polar coordinates.
Applications:
You can use helical interpolation with form cutters
to machine:
• Large-diameter internal and external threads
• Lubrication grooves
Input
• Total incremental angle of tool traverse on the helix
• Total height of the helix
Input angle
Calculate the incremental polar coordinate angle IPA as follows:
IPA = n . 360°; where
n = number of revolutions of the helical path.
For IPA you can enter any value from –5400° to +5400° (n = ±15).
Input height
Enter the helix height H in the tool axis. The height is calculated as:
H = n x P,
n = number of thread revolutions
P = thread pitch
Radius compensation
Enter the radius compensation for the helix according
to the table at right.
Y
Z
CC
Fig. 5. 39: Helix: a combination of circular and linear paths
Internal thread
Right-hand
Left-hand
Right-hand
Left-hand
External thread
Right-hand
Left-hand
Right-hand
Left-hand
Work direction
Z+
Z+
Z-
Z-
Work direction
Z+
Z+
Z-
Z-
Rotation
DR+
DR-
DR-
DR+
Rotation
DR+
DR-
DR-
DR+
Radius comp.
RL
RR
RR
RL
Radius comp.
RR
RL
RL
RR
Fig. 5.40: The shape of the helix determines the direction of rotation
and the radius compensation
X
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