Helix - HEIDENHAIN TNC 620 User Manual

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:
Total height h:
Incremental total angle
G91 H:
Starting coordinate Z:
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
Right-hand Z+
Left-hand Z+
Right-hand Z–
Left-hand Z–
External thread
Right-hand Z+
Left-hand Z+
Right-hand Z–
Left-hand Z–
HEIDENHAIN | TNC 620 | ISO Programming User's Manual | 9/2016
Thread revolutions + overrun at start and
end of thread
Thread pitch P times thread revolutions
n
Thread revolutions x 360° + angle for
beginning of thread + angle for thread
overrun
Pitch P times (thread revolutions +
thread overrun at start of thread)
Path contours – Polar coordinates
Direction of rotation
G13
G12
G12
G13
G13
G12
G12
G13
6.5
Radius compensation
G41
G42
G42
G41
G42
G41
G41
G42
267
6