Correct Traceability in Flexible and Complex Dimensional Metrology. Uncertainty in coordinate metrology: - Needs - Standards.

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Measurement service and metrological development on request in the Technology Park of Gijón (Asturias) Here is

Metrology by Eugen Trapet, ISM3D (Gijón, Spain) Index of Contents Needs and standards for uncertainty

legal aspects - responsability aspects Related Standards (CMM verification) Calibrated master parts - concept

routine Calibration of the master parts: The Virtual CMM gives traceability to nearly any measurement task -

Prüfprozesseignung = Capability of the measurment process - ISO 453-: Rules for the acceptance and rejection

] - ISO 453-: Guide for the calculation of uncertainty in industrial measurements.

1 Measurement service and metrological development on request in the Technology Park of Gijón (Asturias) Here is the laboratory of ISM3D, 0 m below the ground level Correct Traceability in Flexible and Complex Dimensional Metrology by Eugen Trapet, ISM3D (Gijón, Spain) Index of Contents Needs and standards for uncertainty estimation for CMM measurements - correct use of measuring equipment to control manufacturing procecces - legal aspects - responsability aspects Related Standards (CMM verification) Calibrated master parts - concept - formulae Examples for the use of master parts How to introduce uncertainty into the daily measurement routine Calibration of the master parts: The Virtual CMM gives traceability to nearly any measurement task - concept - examples Conclusion Uncertainty in coordinate metrology: - Needs - Standards Standards VDI/VDE 67-8: Prüfprozesseignung = Capability of the measurment process - ISO 453-: Rules for the acceptance and rejection [taking into account the uncertainties.] - ISO 453-: Guide for the calculation of uncertainty in industrial measurements. - VDI/VDE 67-8: Capability of verification processes ( capability ), - VDA 5: Quality control in automotion Range of accordance - ISO/TS , 4, : Methods to estimate measurement uncertainty - EA-G7: Calibration of MCs [and with MCs]

VDI/VDE 67-8: Capability of the measurement/verification process Measurement process capability Individual acceptable limit (may be company specific) g pp = U pp / T g pp <= G pp Analyze

The Virtual CMM Method Analyze uncertainty using (example of such a master part) Calibration of Master Part ISO/TS 5530-4 simulation / Monte Carlo Suited Part Master Part CMM in production: traceable

2 VDI/VDE 67-8: Capability of the measurement/verification process Measurement process capability Individual acceptable limit (may be company specific) g pp = U pp / T g pp <= G pp Analyze uncertainties with the méthod of calibrated objects. In VDA 5 Anex un G pp of is recommended (concept) How to make master parts traceable? The Virtual CMM Method Analyze uncertainty using (example of such a master part) Calibration of Master Part ISO/TS simulation / Monte Carlo Suited Part Master Part CMM in production: traceable according to ISO TS (Master Part Method) Production Produced parts Analyze uncertainty with master parts. Here an experiment using a calibrated master part from sheet metal at VW Mexico Example of sheet metal measurement Puntos de superficies libres One analyzes points of interest

Analyze uncertainty using Formulas Analyze uncertainty using Formulas Systematic error (average deviation from the calibrated values of the master part) Uncertainty of the calibrated feature Standard

3 Analyze uncertainty using Formulas Analyze uncertainty using Formulas Systematic error (average deviation from the calibrated values of the master part) Uncertainty of the calibrated feature Standard deviation when measuring the individual feature of the master part Influences from the work piece. as far as not accounted for in umeasprocess Influence from temperature. as far as not accounted for in umeasprocess E = y y CalStd u CalStd = U / k average of all deviations of results Calibrated value of the measurand according to the calibration certificate of the master part Uncertainty (k=, 95%) of the measurand according to the calibration certificate of the master part U = k E + ucalstd + umeasprocess + uworkpiece + ( Uncertainty of one specific feature / measurement result) u temp u Meas Process = ( n ) n i ( y y) i= Standard deviation of all measurements made on real parts Analyze uncertainty using Formulas 3 u = m ( ) ( E ) m E WorkPiece i i= Standard deviation from spread of results (several different real parts should be studied) Examples for Master Part Method Example of masetr part: Example of master part: Objeto de referencia tubo Different real parts Let s analyze the coordinate X of this node Experiment work piece influence workpiece workpiece workpiece 3 workpiece 4 cycle cycle cycle cycle cycle averages per orientation y u w x y z X-coordinates of one node x y z 3

Example of masetr part: Example of master part: X-coordinates of one node of the master part (!) Resulting uncertainty of feature E 0.66 syst error (abs) u.036 combined uncertainty k.

397 expanded uncertainty of the result, incl syst errors Recommendation to introduce the unjcertainty issue in daily practice: The Feature-Uncertainty List Recommendations for how to start PAMS

4 Example of masetr part: Example of master part: X-coordinates of one node of the master part (!) Resulting uncertainty of feature E 0.66 syst error (abs) u.036 combined uncertainty k.00 coverge factor U.397 expanded uncertainty of the result, incl syst errors Recommendation to introduce the unjcertainty issue in daily practice: The Feature-Uncertainty List Recommendations for how to start PAMS Method Virtual CMM Concept: Simulation for Uncertainty Calculation (on line, measurement software integrated) There is a shortcut for implementing the master part method: The PAMS Method The PAMS Method is a measurement software integrated point wise correction and uncertainty estimation tool It requires a software option and it requires the point wise calibration of the master part The PAMS Method can easier handle form deviations and CADcomparisons than the classical Master Part Method 4

The food for the Virtual CMM is the exhaustive

accredited laboratory - Validation of the Virtual

5530-4 and VDI/VDE 67-7 describe possible metods

simulation One has to validate the reported

roughness: spheres, cylinders, planes, ball

measurands must be meaured - lengths, sizes -

roundness, straightness, flatness) - coaxiality,

calibrated values within the limits set by the

reference and the uncertainty reported by the

Virtual CMM Validation with extremely precise

used by ISM3D for reporting uncertainty in

5 The food for the Virtual CMM is the exhaustive calibration of the CMM - preferably by an accredited laboratory - Validation of the Virtual CMM in each case of such a calibration ISO/TS and VDI/VDE 67-7 describe possible metods to validate the proper functioning of the simulation One has to validate the reported uncertainty using real parts with independently calibrated features. Parts with very small form errors and small roughness: spheres, cylinders, planes, ball plates, gage blocks, step gages Different measurands must be meaured - lengths, sizes - angles (small, big) - form (cylindricity, roundness, straightness, flatness) - coaxiality, concentricity The results must correspond to the calibrated values within the limits set by the calibration uncertainty of the features on the reference and the uncertainty reported by the Virtual CMM for the specific feature in each case Virtual CMM Validation with extremely precise Multi-Feature Standard (principle) Virtual CMM used by ISM3D for reporting uncertainty in Spanish intercomparison; organized by SIL INGENIERÍA SL Virtual CMM Validation with extremely precise cylinder square standard (protocol) Virtual CMM used by ISM3D for reporting uncertainty in Spanish intercomparison; organized by SIL INGENIERÍA SL 5

Virtual CMM used by ISM3D for reporting uncertainty in Spanish intercomparison; organized by SIL INGENIERÍA SL Calibrated Artefact Multi-Feature Check (EUMETRON

0040 67.003 0.0040 67.9593 0.004 0 68.09 0.0040 3.0433 0.

uncertainty in all measurements and verifications of parts From all methods practised, the master part method is the easiest to use We need an infrastructure to

6 Virtual CMM used by ISM3D for reporting uncertainty in Spanish intercomparison; organized by SIL INGENIERÍA SL Calibrated Artefact Multi-Feature Check (EUMETRON Germany) to analyze uncertainty of CMM measurements Valor real Valor nom. Incertidumbre de medición Tol. Sup. Tol. Inf. Desvío Ideal Intercomparison Object with good surface properties (from EU Project EASYTRAC ) Conclusion We have to comply with ISO 453- and includ statements of uncertainty in all measurements and verifications of parts From all methods practised, the master part method is the easiest to use We need an infrastructure to calibrate such master parts (ISO 705 accredited laboratorios) that base their calibrations on absolute methods to calculate uncertainty (Virtual CMM, multi-position, expert method) We need an assistance service to implement the concept of master parts in the industrial practice 6

Temperature Effects in Dimensional Metrology Influences of Temperature on the Accuracy and how to cope with them

Measurement service and metrological development on request in the Technology Park of Gijón (Asturias) Here is the laboratory of ISM3D, 10 m below the ground level Temperature Effects in Dimensional Metrology