Siemens SINUMERIK 840D sl Programming Manual page 143

Preconditions
● The probe must be active as tool.
● Tool type of the probe:
Note
When measuring circle segments of < 90 degrees, it should be noted that, mathematically
speaking, measuring points that deviate from the circular shape exert a particularly great
influence on the accuracy of the results (center point, diameter).
For this reason, an especially high degree of care should be taken when measuring small
circle segments. Good results can be attained if the following procedures are used:
The circle segment to be measured should be:
 Free from machining residue.
 Have as exact a circular form as possible, guaranteed by the machining technology.
 Have as smooth a surface as possible, guaranteed by the machining technology.
 Measured with high-quality probes, i.e. the shape of the probe ball is as homogeneous as
 Measured with four points (setting via parameters).
 Measured with a recently calibrated probe.
Starting position before the measurement
The probe should be positioned in the 3rd axis of the plane (tool axis) at the required
measuring height, approx. at a distance of the measuring path DFA in front of the first
measuring point.
Position after the end of the measuring cycle
At the end of the measurement, the probe ball circumference is a distance of the measuring
path DFA radially from the last measuring point at the measuring height.
NOTICE
The range of the measuring cycle starting points with regard to the circle segment center
point must be within the value of the measuring path DFA, otherwise, there is danger of
collision or the measurement cannot be performed!
Measuring cycles
Programming Manual, 02/2011, 6FC5398-4BP40-0BA0
– 3D multi probe (type 710)
– Mono probe (type 712)
possible.
Measuring variants
2.3 Measure workpiece (milling)
143