4. Measuring geometric errors

Determining one or more of these errors is necessary in the following cases:

• during initial CMM assembly;

• after moving the CMM;

• after a maintenance operation ;

• when creating or modifying the error correction matrix.

• Types of geometric error: for a CMM, there are 21 basic parameters:

  • positioning accuracy and hysteresis (1 parameter per axis) 3

  • orthogonality (1 parameter per plane) 3

  • translation: straightness deviations (2 parameters per axis) 6

  • rotation: yaw, pitch, roll (3 parameters per axis) 9

  • Total:...