For on-machine measurement of workpiece position, orientation, and geometry on machine tools, five-axis continuous (scanning) measurement by using a laser displacement sensor has a strong advantage in its efficiency, compared to conventional discrete measurement using a touch-triggered contact probe. In any on-machine 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 five-axis on-machine measurement by using a laser displacement sensor. To validate the present simulator, experimental comparison of measured and simulated trajectories is conducted on five-axis on-machine 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 low-pass filtered) was at maximum 5 lm. Uncertainty assessment demonstration for more practical application example of a turbine blade measurement is also presented.

A triangulation-based laser displacement sensor using the diffuse reflection light has a strong practical advantage in its robustness against the tilting of the object surface to the sensor's sensitive direction. On the other hand, it is often subject to higher-frequency noise-like measurement error in scanning operations. This error is caused by the movement of the speckle in the reflected laser beam spot with the scanning operation. This paper first discusses how the dual-view triangulation, using two image sensors aligned symmetrically about the laser beam axis, can reduce the scanning noise in principle. Then, its inherent limitation is discussed. Since different points on the target surface cast the specular reflection to each image sensor, the influence of the sensor's lateral movement cannot be canceled by comparing the reflected spot's displacement on each image sensor. This issue can be observed clearer when measuring a surface of a less random surface profile. It is experimentally validated.

In this paper, the measurement error of a diffusereflection-type laser displacement sensor is analyzed for profile measurement. Multi-reflection error is predicted by a simple-beam-tracking simulation. Based on the simulation results, the measurement range of a laser displacement sensor is tuned, and multireflection error is reduced. Then, measurement errors in the experimental measurement of a small die are evaluated.

For the efficiency of machining of high-precision parts, their on-machine measurement plays a very important role. Laser displacement sensors enable high speed measurement with cost effectiveness. However, laser displacement sensors are potentially subject to several measurement errors. In this paper, the measurement error of a diffuse-reflection-type laser displacement sensor is analyzed for profile measurement. To this end, multi-reflection error is predicted by a simple beam tracking simulation. Based on the simulation result, the measurement range of a laser displacement sensor is tuned narrower to reduce multi-reflection error. Then, measurement errors were evaluated.