Siemens SINUMERIK 840D sl Programming Manual page 240

Measuring Cycles for Milling and Machining Centers
5.10 CYCLE996 workpiece: Measure kinematics
Mounting the calibration ball
In the case of machinery, the calibration ball is to be installed on the machine table.
In order to measure swivel data records for swivel-mounted workholders, the ball must be
incorporated into the appropriate workholder. In all cases it must be ensured that the probe
can approach and bypass the mounted calibration ball without collision in all the selected
rotary axis positions.
Considering the need to avoid collisions, the calibration ball should be mounted as far as
possible from the center of rotation of the rotary axis that is to be measured.
If the three ball positions result in too small a triangle, this will negatively affect the accuracy
of the procedure:
Calibration ball mounted sufficiently far from
the center of rotation; large triangle can be
clamped
Note
While measuring a rotary axis, the mechanical hold-down of the calibration ball must not be
altered. It is only with table and mixed kinematics that different calibration ball mounting
positions are permissible for the purpose of measuring the first and subsequent rotary axes.
240
Calibration ball mounted too near the center
of rotation; clamped triangle is too small
Programming Manual, 03/2009 Edition, 6FC5398-4BP10-2BA0
Measuring cycles