Skip navigation

System calibration

It is absolutely crucial that the probe is precisely calibrated for each measurement procedure before measurement is taken. Renishaw recommends using a universal calibration tower (Renishaw part number A-3060-4590) to ensure best metrology performance with the RSP3 range of scanning probes.

The position of the individual ball styli and their diameters should be established using the probe calibration programme recommended by the machine manufacturer (see the manufacturer's manual). Each RSP3 probe configuration should initially be calibrated and A0, B0 before the probe can be calibrated in the required head orientations.

WARNING: It is important, when calibrating the RSP3 probe, that the probe is able to access the full circumference of the calibration sphere perpendicular to the direction of the stylus. Sub optimal performance is achieved when a probe is unable to scan the full circumference of the calibration sphere. For instance, to calibrate a probe at both A0, B0 and A90, B0, the calibration sphere should be mounted with a stalk at 45° to the bed of the CMM.

Calibration with standard gimball datum sphere

RSP3 calibration with gimballed datum sphere - correct and incorrect

Calibration with universal calibration tower

The universal calibration tower enables calibration of RSP2 and RSP3 probes on a common artefact. The tower is compatible with the REVO Ø45 mm datum ball for RSP2 calibration, and up to four standard Ø25 mm datum balls for RSP3 calibration. Twelve separate mounting positions are available, three at each compass point, that allow datum balls to be attached at either +45°, 0° or -45°.

Universal calibration tower

Periodic requalification should be performed under the following circumstances:

  • CMM supplier's recommendations, particularly in respect to temperature changes
  • At the start of the working day or a shift
  • After accidental collision
  • When new probe / stylus configurations are introduced
  • If the initial state is unknown or uncertain