HEIDENHAIN TNC 640 (34059x-04) Cycle programming - Manual (Page 302)

Cycles: Turning
13.2 ADAPT ROTARY COORDINATE SYSTEM
(Cycle 800, DIN/ISO: G800)
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TNC 640 | User's Manual Cycle Programming | 3/2014
Eccentric turning (software option 135)
Sometimes it is not possible to clamp a workpiece such that the
axis of rotation is aligned with the axis of the turning spindle (e.g.
if large or rotationally non-symmetrical workpieces are being used).
The
Q535 eccentric turning function in Cycle 800 enables you to
perform turning operations in such cases as well.
During eccentric turning more than one linear axis is coupled to
the turning spindle. The TNC compensates the eccentricity by
performing circular compensating movements with the coupled
linear axes.
This feature must be enabled and adapted by the
machine tool builder. Refer to your machine manual.
High rotational speeds and large eccentricity require high feed
rates of the linear axes to ensure that they move synchronously. If
these feed rates are not maintained, the contour will be damaged.
The TNC therefore generates an error message if 80 % of a
maximum axis speed or acceleration is exceeded. If this occurs,
reduce the rotational speed.
Do not couple or decouple axes when the turning spindle is
rotating. The TNC performs compensating movements during
coupling and decoupling. Check for possible collisions.
Turn a test cut before the actual machining operation
to ensure that the required speeds can be attained.
The linear axis positions resulting from the
compensation are displayed by the TNC only in the
ACTUAL value position display.
The rotation of the workpiece creates centrifugal
forces that can cause vibration (resonance),
depending on the unbalance. This vibration has
a negative effect on the machining process and
reduces the tool life. High centrifugal forces can
damage the machine or push the workpiece out of
the fixture.
Danger of collision!
Collision monitoring (DCM) is not active during
eccentric turning. The TNC displays a corresponding
warning during eccentric turning.