HEIDENHAIN TNC 640, User Manual, Page: 682 / 948

Turning | Unbalance functions (option 50)
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
16.3 Unbalance functions (option 50)
Unbalance while turning
General information
Refer to your machine manual.
Unbalance functions are not required and available on all
machine tool types.
The unbalance functions described here are basic
functions that are set up and adapted to the machine by
the machine manufacturer. The scope and effect of the
described functions may therefore vary from machine to
machine. The machine manufacturer may also provide
different unbalance functions.
In a turning operation, the tool is in a fixed position, whereas the
rotary table and the clamped workpiece rotate. Depending on the
size of the workpiece, the mass that is set in rotation can be very
large. As the workpiece rotates, it creates an outward centrifugal
force.
The centrifugal force that occurs basically depends on the rotational
speed, the mass and the unbalance of the workpiece. When a
body whose mass distribution is not rotationally symmetric is put
into a rotary motion, this leads to an unbalance. If the mass object
is rotating, this creates outward-acting centrifugal forces. If the
rotating mass is evenly distributed, the centrifugal forces cancel
each other out.
The unbalance is significantly influenced by the structural shape
of the workpiece (e.g. an asymmetric pump housing) and by
the clamping devices. Because these conditions can often not
be changed, compensate any existing unbalance by clamping a
balancing weight. The controls provides the
MEASURE UNBALANCE
cycle for this purpose. The cycle determines the existing unbalance
and calculates the mass and position of the required balancing
mass.
In the NC program, Cycle 892
CHECK IMBALANCE
checks whether
the entered parameters are exceeded.
NOTICE
Caution: Significant property damage!
Very high physical forces are generated during turning, for
example by high rotational speeds and heavy or unbalanced
workpieces. Incorrect machining parameters, neglected
unbalances or improper fixtures lead to an increased risk of
accidents during machining!
Clamp the workpiece in the spindle center
Clamp workpiece securely
Program low spindle speeds (increase as required)
Limit the spindle speed (increase as required)
Eliminate unbalance (calibrate)