A reduced self-calibrating method for rotary table error motions

A novel method for the determination of rotary table errors with six degrees of freedom on coordinate measuring machines and machine tools is introduced. The method is based on the measurement of an uncalibrated circular ball plate in different rotational positions on the rotary table, which is also referred to as the three-rosette method. The novel procedure allows the number of measurement positions to be reduced significantly compared to the complete three-rosette method, while the measurement uncertainty still remains sufficiently small. The method relies on error separation and is self-calibrating, which means that no external reference is required. The sophisticated design of a new ball plate allows rotary table errors to be determined in angular steps of only 5∘.