MEASUREMENT MODELS – THEORY AND PRACTICE OF UNCERTAINTY EVALUATION OF GEOMETRICAL DEVIATION MEASUREMENTS

Abstract

The publication provides a critical analysis of fundamental documents concerning the determination of measurement uncertainty from the perspective of the machinery industry. The requirements contained in the documents JCGM 104, JCGM 100, and JCGM 101 were compared with important documents used in geometrical measurements, particularly with EA-4/02, ISO 14253-2, ISO/TS 15530-1, ISO 15530-3, ISO/TS 15530-4, and VDI/VDE 2617-11. Significant differences between the documents analysed, both terminological and interpretative, were highlighted. The analysis was performed in the sequence of stages for determining measurement uncertainty: formulation, propagation, and summarizing. Special attention was paid to the problem of defining the measurement model and the insufficient reference to the measurement model in the analysed documents. Attention was drawn to the wide range of characteristics measured in the machinery industry, such as linear and angular dimensions and form, orientation, position, and runout deviations, as well as the wide range of measurement equipment used, from simple instruments like callipers, micrometers, and mechanical dial gauges, to coordinate measuring machines and measurement systems. The current approach to the uncertainty of coordinate measurements, including the new possibility of modelling coordinate measurement, was discussed.