Wojciech Płowucha, Władysław Jakubiec University of Bielsko-Biała, Laboratory of Metrology

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1 Wojciech Płowucha, Władysław Jakubiec University of Bielsko-Biała, Laboratory Laboratorium of Metrology Metrologii

2 Laboratory Laboratorium of Metrology Metrologii

3 Laboratory Laboratorium of Metrology Metrologii

4 Calibration of CMMs, ACMM, microscopes, measuring projectors, special geometrical gauges. Laboratory Laboratorium of Metrology Metrologii

5 Coordinate measuring technique (CMT) quickly developing and widely present in the industry (not only machine) measurement technology. Geometrical product specification (GPS) intensive standardization works are underway (ISO TC 213) aimed at organizing, clarifying and filling gaps in a large series (almost 100) of standards. Measurement uncertainty the problem is generally known, but it is not easy (especially in the case of coordinate measuring technique), and recently the quality management systems used in industry require that the uncertainty is "known and appropriate". Laboratory Laboratorium of Metrology Metrologii

6 Coordinate measuring technique Tactile (touch-trigger, scanning) with rotary table (fourth axis) Optical and multisensor

7 Coordinate measuring technique ACMM articulated measuring arms

8 Coordinate measuring technique laser-tracers

9 Coordinate measuring technique CT computed tomography

10 Coordinate measuring technique Optical scanners

11 Coordinate measuring technique in comparison with conventional measurements (examples) Measurement of size (diameter) Conventional measurement: - caliper, micrometer two-point measurement, - bore-gage three-point measurement, - gauges realization of Taylor pronciple (E), - circumference measurement devices. Coordinate measurement: - Tactile measurements: significant numer of probing points; result is associated circle (in particular section) or cylinder; different association criteria may be applied, calculation of twopoint diameter possible if required, - Optical measurement: as above.

12 Coordinate measuring technique in comparison with conventional measurements (examples) Gears measurements Conventional measurement: - Special measuring devices a required to measure diffenet characteristics Coordinate measuring technique: - CMM-evaluation-software option required; some characteristics may be evaluated virtualy

13 Coordinate measuring technique in comparison with conventional measurements - summary Advantages of Coordinate measuring technique - necessity for large number of different measuring devices (special devices in particular) is eliminated. - the time of starting a new production is reduced (the time needed to "write" the measurement program is definitely shorter than the time needed to design and manufacture a special device) - with CMT it s easier to implement design changes during production (short time for updating measuring programmes) LM ATH LM had the opportunity to participate in the implementation of a new product for production at Avio Bielsko-Biała (a set of blades) where for the first time the special measuring instruments were replaced with direct CMM measurement.

14 Coordinate measuring technique in comparison with conventional measurements - summary Special requirements - Measurement of roughness on CMM development is ongoing, some solutions are available (even for machine tools), - Measurement of small radii and edges these are important characteristics in some applications (fatigue strength) In short time no complex solution can be expected.

15 Sources of uncertainty GPS&V Source: A. Weckenmann

16 CMM software Post-inspection Statistical analysis Graphical presentation Analysis of measurement uncertainty Computer Aided Accuracy CAA Geometrical error correction Thermal effects correction Programming Offline programming and simulation Parametric programming Feature oriented programming ISO Core software Probing system qualification Coordinate system definition and manipulation Association of geometrical features Relations between geometrical features (distance, angle, intersections, ) Geometrical deviations evaluation Tolerances analysis (OK, NOK)??? Specialized options Gears Threads Camshafts Freeform surfaces Reverse engineering Accesories Multisensor Probe changer Rotary table Automatic workpiece handling Multicolumn CMMs

17 What we measure? Geometrical characteristics Sizes Dimensions other than sizes Geometrical tolerances According to the modern approach of GPS, the toleranced dimensions should only be used for features of size.

18 Structure of the ISO GPS system 3 type of standards are distinguished: fundamental, general and complementary. Standards follow a 9 x 7 matrix system. Rows (9) are geometrical properties. Columns (7) are chain links. Geometrical properties: - size, - distance, - form, - orientation, - location, - run-out, - profile surface texture, - areal surface texture, - surface imperfections Chain links: A: Symbols and indications, B: Feature requirements, C: Feature properties, D: Conformance and non-conformance, E: Measurement, F: Measurement equipment, G: Calibration The GPS standards standards relate to geometric properties as a whole (not only designation symbols to express the requirements but also all aspects concerned with verification). It s often misinterpreted that GPS is synonymous with GD&T. The chain links B and C clearly refer to the coordinate technique.

19 Main GPS standards ISO 286 (1988, 2010) Geometrical product specifications (GPS). ISO code system for tolerances on linear sizes. Part 1: Basis of tolerances, deviations and fits ISO (2016) Geometrical product specifications (GPS). Dimensional tolerancing. Part 1: Linear sizes ISO (2011) Geometrical product specifications (GPS). Dimensional tolerancing. Part 2: Dimensions other than linear sizes ISO 1101 (2006, 2012, 2017) Geometrical product specifications (GPS). Geometrical tolerancing. Tolerances of form, orientation, location and run-out ISO 5459 (2011) Geometrical product specifications (GPS). Geometrical tolerancing. Datums and datum systems

20 Features of size The features of size are shafts and holes as defined in ISO 286, namely cylindrical elements or pairs of parallel planes.

21 Sizes according to ISO

22 Sizes Basic interpretation of size is local twopoint size. Such interpretation does not require special designation. Other interpretation of size, very often applied, is global size understood as size of feature calculated with one of following association criteria: Gaussian (GG) (Fig. a), maximum inscribed (GX) (Fig. b), minimum circumscribed (GN) (Fig. b) or minimax (GC).

23 Sizes In case of envelope requirement (modifier (E)) the verification of the product geometry practically consists on simultaneous check for fulfilling the two requirements mentioned previously.

24 CMM verification of GG size

25 CMM verification of LP (min, max) size

26 CMM verification of envelope requirement E (LP + GN)

27 Example D = 363,22 +/-0,04 D(LP) = (363, ,2625) (297 values) Frequency D(LP) D(GG) = 363,2503 D(E) = 363,2751

28 Verification of size as distance of two parallel planes

29 Dimensions other than size

30 Dimensions other than size

31 Example: specification of requirements for bearings GN minimum circumscribed size LP two-point size ALS any longitudinal section Intersection plane indicator (symmetry) (applies to the crossection symmetrical with datum K which is the hole axis) A B between A and B ; defines length of the toleranced element (applies to the perpendicularity of the outer ring axis) aaa SR range of sizes SD standard deviation of sizes ACS any cross section

32 Geometrical tolerances (ISO 1101) Classification: Form Orientation Location Run-out Tolerances of orientation limit form deviations. Tolerances of location limit form and orientation deviations.

33 Datums as tangential elements

34 Datums as tangential elements Evaluation method for datum assignment Evaluation method for the measurement

35 Perfect verification operator for perpendicularity No direct solution in CMM software: Form deviation of the toleranced feature is not taken into account

36 Laboratory Laboratorium of Metrology Metrologii

37 Laboratory Laboratorium of Metrology Metrologii

38 Laboratory Laboratorium of Metrology Metrologii

39 n11 EUCoM Standards for the evaluation of the uncertainty of coordinate measurements in industry Laboratory Laboratorium of Metrology Metrologii

40 n11 EUCoM Standards for the evaluation of the uncertainty of coordinate measurements in industry Objectives: 1. To develop traceable and standardised methods for evaluating coordinate measurements a posteriori. This should include the improvement of existing methods in EN ISO and pren ISO To develop a simplified and validated method for predicting the uncertainty of coordinating measurements a priori using type B evaluation (i.e. expert judgement). 3. To demonstrate the validity of existing methods and those from objective 1 & 2 in industrial conditions and evaluate their consistency and accuracy against the Guide to the Expression of Uncertainty in Measurement (GUM) and its supplements. 4. To contribute to revisions of EN ISO and EN ISO by providing the necessary data, methods, guidelines and recommendations, in a form that can be incorporated into the standards at the earliest opportunity. In addition, to collaborate with the technical committees CEN TC 290 and ISO TC 213 WG10 and the users of the standards they develop to ensure that the outputs of the project are aligned with their needs and recommendations for incorporation of this information into future standards at the earliest opportunity. Laboratory Laboratorium of Metrology Metrologii lm@ath.eu