Simulation model for uncertainty estimation of measurements performed on five-axis measuring systems

Abstract

Five-axis measuring systems (i.e. coordinate measuring machines equipped with articulated probe heads capable of continuous indexation or five-axis machine tools with inspection probe mounted on a tilt and swivel head) are becoming more and more popular, especially in industrial applications, since their usage speeds up the measurement process without significant loss in accuracy. Widespread adoption of these systems necessitates development of viable and easy-to-use measurement uncertainty estimation methods. This paper describes the experiments required for identification of errors of five-axis measuring systems based on usage of LasrTracer system and measurements of ring standard. It also expounds the methodology for implementation of virtual CMM-based simulation model for these systems giving the explanation on all input quantities used in the model along with detailed mathematical explanations on uncertainty propagation procedure. Eventually, it presents the validation methodology and the results of validation measurements performed in order to prove the correct functioning of developed model. Basing on these results, the main conclusion drawn in the paper is that presented virtual model should be regarded as working properly and producing metrologically correct values of measurement uncertainty for common metrological tasks known from GD&T framework.

New European Metrology Network for advanced manufacturing

“…The publications of high value for the EMN are located in the upper right-hand quadrant, where the quality is rated highest and the number of mentioned gaps is between 6 and 12. Of the 145 analysed publications, 11 are considered particularly valuable [22][23][24][25][26][27][28][29][30][31][32].…”

The modelling of the measuring point reproduction error for optical coordinate measuring machines

“…Such a structure was adapted using various solutions that have been developed over the years by different research centres. One of the significant conceptions was developed in the Laboratory of Coordinate Metrology (LCM), it assumes that the accuracy of point coordinate measurement can be described by means of residual error distribution [5,6], i.e. errors that remain after the application of systematic error compensation methods.…”

“…Residual errors are determined in certain points covering the measuring volume of the machine, which is comprised of a reference grid of points. The errors can be experimentally determined by, for example, measurements of standard elements (hole plate, ball standards) [4] or using other devices like laser tracking systems [5,6]. However, because residual errors also accommodate random errors, the results obtained during experiments should not be treated as exact error values but rather as information about the probability with which the reference points can be reproduced by the machine.…”

“…Because the distribution of results can be different for each measuring axis, it can be described for a 2D case as an ellipse (according to [7]) and for a 3D case as an ellipsoid [4]. The virtual machine described in detail in [5] uses ellipsoids of point reproduction probability. A laser tracking system is used for the determination of the position of the retroreflector which is mounted in the place of the CMM's probing system.…”

Assessment of Influence of Sample Averaging on Accuracy of Point Coordinates Measurement Performed Using Laser Tracking Systems

“…Such approach fits in with the trend of reducing the manufacturing time which includes also time needed for accuracy assessment of the measurements results obtained during the quality control stage. The so called "Virtual models" of different systems were successfully developed for different measuring systems [5,10]. During development of such models several challenges must be overcome, including: identification and modelling of main sources of errors during measurements [2] and proper model validation [6].…”