Impact of warm-up period on optical coordinate measuring machine measurement accuracy

The multisensor optical coordinate measuring machines utilizes various systems used for point coordinates acquisitions. Different sources of light, power supply units and other electric devices along with motors responsible for machine movement along coordinate system axes introduces temperature variation into its measuring volume. It may be especially problematic after turning a machine on as it took some time before temperature of system stabilize. This paper tries to answer if accurate measurements can be performed during machine warm-up period. Applied methodology is based on the measurements of hole plate standard performed during machine warm-up and after a temperature stabilization. Additionally the amount of time needed for the temperature stabilization can be estimated. Obtained results show that although utilized temperature compensation reduce systematic errors related with temperature variations, the warm-up period may introduce the noticeable change of point measurement uncertainty.