Zeiss CenterMax, Руководство по эксплуатации

Страница: 132 / 166

7-32
Measuring operation
61211-1020202 CenterMax Operating Instructions
Evaluating the measuring data
Limiting values for deviations
Standard deviation
The result is evaluated based on the standard deviation. There is no
maximum standard deviation which applies to all applications. The
tolerable deviation depends on many factors: e.g. resolution and pre-
cision of the CMM, length and rigidity of the probe shaft, quality of
the probe tip, cleanness of the environment. Normally, the standard
deviation should be within the range of a few micrometers (e.g.
0.002 [mm]).
It might be necessary to decide whether or not to accept measuring
inaccuracies.
Causes of large deviations
The sources of error which may lead to increased deviations are listed
in the following.
Source of error Cause
Reference point – No reference point travel has been carried out.
– No reference measurement has been carried out.
Calibration – Different axis clamping than for calibration
– Different measuring force than for calibration (with VAST)
Temperature compensation – Temperature compensation has not been carried out.
– Incorrect temperature compensation.
Probe design – Probe design is not stable.
– Probe components are not screwed together firmly enough.
– Permissible probe limiting values have not been observed.
The probe is too long, too heavy or contains components which
are not suitable.
Probe status – Calibration sphere or probe element is soiled, oiled-up or dam-
aged.
– Probe components or adapter plate are/is damaged.
Magnetic field – A fault was caused by a magnetic field.
Possible causes of a magnetic field: e.g. workpiece, clamping tool,
probe extensions.
Probing – Probing was not carried out perpendicular to the probing surface.