DIN EN ISO 15530-3:2012-01

This standard has been prepared by Working Group ISO/TC 213/WG 10 "Coordinate measuring machines" with substantial collaboration by German experts. On the national level, Joint Working Committee NA 152-03-02-12 UA "Koordinatenmesstechnik (GMA 3.31)" ("Coordinate Metrology (GMA 3.31)") is responsible for the revision. CEN/TC 290 is responsible on the European level. This part of ISO 15530 specifies the evaluation of measurement uncertainty for results of measurements obtained by a CMM by using calibrated workpieces. It provides an experimental technique for simplifying the uncertainty evaluation of CMM measurements, whose approach (substitution measurements) leads to measurements being carried out in the same way as actual measurements, but with calibrated workpieces of similar dimension and geometry instead of the unknown workpieces to be measured. Non-substitution measurements on CMMs are also covered, as are the requirements of the uncertainty evaluation procedure, the measurement equipment needed, and the reverification and interim check of the measurement uncertainty. The evaluation of measurement uncertainty is always related to a specific measuring task. Coordinate measuring machines (CMMs) have become essential for the verification of geometry in industry. According to the ISO 9000 series of standards the relevant measuring equipment in a quality management system is required to be calibrated against certified equipment having a known and valid relationship to internationally or nationally recognized standards in order to establish traceability. According to the International vocabulary of basic and general terms in metrology (VIM), a calibration comprises - besides the establishment of the relationship between the measured and the correct values of a quantity - the uncertainty evaluation in the final results (measurands) of the measurement task. However, uncertainty evaluation methods covering the errors arising in the innumerable measurement tasks a CMM can actually perform are often very complex. In these cases, the risk of an unrealistic estimation of task-related uncertainty is likely to arise. The aim of this document is to provide an experimental technique for simplifying the uncertainty evaluation of coordinate measuring machine measurements. In this experimental approach, measurements are carried out in the same way as actual measurements, but with calibrated workpieces or measurement standards of similar dimension and geometry instead of the unknown objects to be measured. The description of this experimental technique to evaluate measurement uncertainty is the key element of this part of the document. The standardization of such procedures for the uncertainty evaluation serves the worldwide mutual recognition of calibrations and other measurement results. This document is applicable for non-substitution measurement of workpieces or measurement standards, where the measurement result is given by the indication of the CMM. Furthermore, it is applicable for substitution measurement, where, in opposition to the non-substitution measurement, a check standard is used to correct for the systematic errors of the CMM. The latter will generally decrease the measurement uncertainty and is often used, especially in the field of gauge calibration. The engineering standard describes one of several methods of uncertainty evaluation. Because of the experimental approach, it is simple to perform, and it provides realistic statements of measurement uncertainties. The limitations of this method can be summarized as: the availability of artefacts with sufficiently defined geometrical characteristics, stability, reasonable costs, and the possibility of being calibrated with sufficiently small uncertainty. The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 10360-1:2000, Geometrical Product Specifications (GPS) - Acceptance and reverification tests for coordinate measuring machines (CMM) - Part 1: Vocabulary International vocabulary of basic and general terms in metrology (VIM). BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, 2nd edition, 1993. Guide to the expression of uncertainty in measurement (GUM). BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, 1st edition, 1993, corrected and reprinted in 1995. Bibliography: DIN V 32950, Geometrical product specification (GPS) - Masterplan, DIN V EN ENV, Guide to the expression of uncertainty in measurement, DIN EN ISO 10360-1, Geometrical Product Specifications (GPS) - Acceptance and reverification tests for coordinate measuring machines (CCM) - Part 1: Vocabulary