HEIDENHAIN TNC 620 (81760x-02) - Manual (Page 233)

Path contours – Polar coordinates 6.5
6
TNC 620 | User's Manual
HEIDENHAIN Conversational Programming | 2/2015 233
Helix
A helix is a combination of a circular movement in a main plane and
a linear movement perpendicular to this plane. You program the
circular path in a main plane.
A helix is programmed only in polar coordinates.
Application
Large-diameter internal and external threads
Lubrication grooves
Calculating the helix
To program a helix, you must enter the total angle through which
the tool is to move on the helix in incremental dimensions, and the
total height of the helix.
Thread revolutions n:
Thread revolutions + overrun at start and
end of thread
Total height h: Thread pitch P times thread revolutions
n
Incremental total angle
IPA:
Thread revolutions x 360° + angle for
beginning of thread + angle for thread
overrun
Starting coordinate Z: Pitch P times (thread revolutions +
thread overrun at start of thread)
Shape of the helix
The table below illustrates in which way the shape of the helix is
determined by the work direction, direction of rotation and radius
compensation.
Internal thread Work direction Direction of rotation Radius compensation
Right-hand
Left-hand
Z+
Z+
DR+
DR–
RL
RR
Right-hand
Left-hand
Z–
Z–
DR–
DR+
RR
RL
External thread
Right-hand
Left-hand
Z+
Z+
DR+
DR–
RR
RL
Right-hand
Left-hand
Z–
Z–
DR–
DR+
RL
RR