Formulation of Influence of Machine Geometric Errors on Five Axis On Machine Scanning Measurement by Using a Laser Displacement Sensor

Abstract

For onmachine measurement of workpiece position, orientation, and geometry on machine tools, fiveaxis continuous (scanning) measurement by using a laser displacement sensor has a strong advantage in its efficiency, compared to conventional discrete measurement using a touchtriggered contact probe. In any onmachine measurement schemes, major contributors to their measurement uncertainty are error motions of the machine tool itself. This paper formulates the influence of geometric errors of rotary axis average lines on the measurement uncertainty of the fiveaxis onmachine measurement by using a laser displacement sensor. To validate the present simulator, experimental comparison of measured and simulated trajectories is conducted on fiveaxis onmachine measurement of a precision sphere of the precalibrated geometry. For total 28 paths measured on the spherical surface, an error in the simulated trajectories from measured trajectories (properly lowpass filtered) was at maximum 5 خ¼m. Uncertainty assessment demonstration for more practical application example of a turbine blade measurement is also presented.