Siemens SINUMERIK 840D sl Programming Manual page 289

Sequence
Position before measuring cycle call
Before the cycle is called, the tool must be
moved to the starting position, as shown in
the diagram for turning tools. The measuring
cycle then calculates the approach position
automatically. This position determines the
measuring direction in the measuring axis
_MA. For milling tools, the measuring point
on the tool is determined by entered lengths
1 and 2 (please note: SD 42950:
TOOL_LENGTH_TYPE). If the radius value
is not equal to zero, this is also a
determining factor. The measuring point is
then located on the side which the
measuring probe faces (+R or –R). The axial
or radial position of the tool must be
specified (_MVAR). This starting position
must ensure collision-free approach.
In the case of milling tools, length and radius can be selected as an alternative to length only
to determine the cutter radius.
For length and radius, two measuring points are required. These are approached from
different sides of the measuring probe. First the measuring point facing the measuring probe
at the starting point is approached. Then, after travel round the probe (in the direction of the
starting point), the 2nd measuring point is measured in the opposite direction. If the spindle
is stationary (M5) and measurement without reversal is selected, the 2nd measurement is
performed with a spindle rotation of 180 degrees. The same cutting edge used for the 1st
measurement is now used.
The L1 or L2 offset values and the cutter radius are calculated from these two
measurements.
Measurement with reversal can be selected separately with _MVAR: First the measuring
point is measured in the selected axis and in a milling spindle position according to starting
angle _STA1. Then the tool (spindle) is turned 180 degrees and measured again. The
average value is the measured value. Measurement with reversal causes a second
measurement at each measuring point P with a spindle rotation through 180 degrees from
the starting angle.
The offset angle entered in _CORA is summated to these 180 degrees. That enables
selection of a certain 2nd milling cutting edge that is offset from the 1st cutting edge by
precisely 180 degrees. Measurement with reversal permits measurement of two cutting
edges of one tool. The mean value is the offset value.
Measuring cycles
Programming Manual, 03/2009 Edition, 6FC5398-4BP10-2BA0
Measuring Cycles for Turning Machines
6.3 CYCLE982 tool: Measure turning and milling tools
289