Static and dynamic measurements of machine tools

Many machine tools have unwanted error motions, either due to their design or due to applied loads or thermal distortions. There are various standard methods to calibrate the machine and to compensate for some of these errors, and static measurement tests have been used for many years for machine tool acceptance. Static tests capture data at a number of target positions along the axis while dynamic tests can now capture thousands of data points while the machine is in motion. This paper reports on dynamic calibration tests performed on machine tools and reveals some previously undetected problems with machine tool accuracy which static tests were unable to detect. The machines that were tested included a large travelling gantry universal machining centre and a travelling column machining centre located in the north of England.