Siemens SINUMERIK 840D sl Programming Manual page 175

Requirements
● The probe must be active as tool.
● Tool type of the probe:
– 3D multi probe (type 710)
– Mono probe (type 712)
Note
The following measuring methods are only possible in the axes of the plane:
● 3D probe with spindle reversal (differential measurement)
● Align 3D probe
The probe types 712, 713 and 714 generally cannot be used for these measuring methods.
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
possible.
● Measured with four points (setting via parameters).
● Measured with a recently calibrated probe.
Starting position before the measurement
The probe is 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. When selecting
this preliminary position in the axes of the plane, the start angle setting must be taken into
account. This is because the first measuring point and all additional ones are shifted on the
circular path through the start angle.
Using a start angle of 180° as example, the first contact point is on the opposite side of the
hole to be measured. If this would not be taken into account for the start position, then the
collision would occur with possible obstructions in the hole.
Measuring cycles
Programming Manual, 12/2017, 6FC5398-4BP40-6BA1
Measuring variants
3.3 Measure workpiece (milling)
175