Helix - HEIDENHAIN TNC 640 User Manual

Programming Contours | Path contours – Polar coordinates

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
Right-hand
Left-hand
Right-hand
Left-hand
External thread
Right-hand
Left-hand
Right-hand
Left-hand
HEIDENHAIN | TNC 640 | ISO Programming User's Manual | 10/2017
Thread revolutions + overrun at start
and end of thread
Thread pitch P times thread revolu-
tions 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)
Work direction
Z+
Z+
Z–
Z–
Z+
Z+
Z–
Z–
Direction of rotation
G13
G12
G12
G13
G13
G12
G12
G13
Radius compensation
G41
G42
G42
G41
G42
G41
G41
G42
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