The KCDB - the BIPM key comparison database – supports the CIPM MRA. The KCDB contains information on the internationally recognized Calibration and Measurement Capabilities (CMCs) for services available from the participating institutes, and the key and supplementary comparisons supporting these CMCs.

All data listed in the KCDB have been reviewed and approved within the CIPM Mutual Recognition Arrangement
MEASURAND : Relative positions of the gauge surfaces with respect to the centre of the front surface of the first gauge

TRAVELLING STANDARD : A 1020 mm long step gauge with 51 steps

Degrees of equivalence: constant component, *D*_{ic} and expanded uncertainty *U*_{ic}

(*k* = 2), and proportional component, *D _{i}*

MEASURAND : Length between the ball centres of each ball bar

Ball bar material : 2 steel ball bars and one Super Invar ball bar

NOMINAL VALUES : 400 mm and 800 mm for steel ball bars and 800 mm for Super Invar ball bar

*L*_{1} = 400 mm, steel ball bar

*L*_{2 }= 800 mm, steel ball bar

Note that NMIJ and NMIA reported no results for steel ball bar with nominal length 800 mm.

*L _{3}* = 800 mm, Super Invar ball bar

Note that NMIJ and NMIA reported no results for Super Invar ball bar with nominal length 800 mm.

MEASURAND : Relative positions of the gauge surfaces with respect to the centre of the front surface of the first gauge

TRAVELLING STANDARD : A 1020 mm long step gauge with 51 steps

Degrees of equivalence: constant component, *D*_{ic} and expanded uncertainty *U*_{ic}

(*k* = 2), and proportional component, *D _{i}*

Results are presented under A4 printable format in Summary Results (.PDF file).

MEASURAND : Length between the ball centres of each ball bar

Ball bar material : 2 steel ball bars and one Super Invar ball bar

NOMINAL VALUES : 400 mm and 800 mm for steel ball bars and 800 mm for Super Invar ball bar

**Degrees of equivalence, D_{i} and expanded uncertainty U_{i} (coverage factor 2), for each ball bar k**

Results are presented under A4 printable format in Summary Results (.PDF file).

EURAMET.L-K5.n01

Metrology area, Sub-field | Length, Dimensional Metrology |

Description | CALIBRATION OF 1D CMM ARTEFACTS (STEP GAUGES) |

Time of measurements | 2022 - 2023 |

Status | Planned |

References | |

Measurand | Distances |

Transfer device | Step gauge of 610 mm |

Comparison type | Key Comparison |

Consultative Committee | CCL (Consultative Committee for Length ) |

Conducted by | EURAMET (European Association of National Metrology Institutes) |

RMO Internal Identifier | EURAMET 1547 |

Comments | Subsequent comparison of EURAMET.L-K5.2016. |

Pilot institute |
GUM
Glowny Urzad Miar, Central Office of Measures Poland |

Contact person | Dariusz Czułek 48 22 581 9543 |

Pilot laboratory | |
---|---|

GUM |
Glowny Urzad Miar, Central Office of Measures, Poland, EURAMET |

BFKH |
Government Office of the Capital City Budapest, Hungary, EURAMET |

CEM |
Centro Español de Metrologia, Spain, EURAMET |

INMETRO |
Instituto Nacional de Metrologia, Qualidade e Tecnologia, Brazil, SIM |

LNE |
Laboratoire national de métrologie et d'essais, France, EURAMET |

MIRS |
Metrology Institute of the Republic of Slovenia, Ministry of the Economy, Tourism and Sport, Slovenia, EURAMET |

NPL |
National Physical Laboratory, United Kingdom, EURAMET |

VSL |
VSL, Netherlands, EURAMET |

This page proposes print-out on A4 paper (portrait) of the comparison details (best printed out using a black and white printer).

Please, select items to be printed out, then click on "OK" :

Results:

MEASURAND : Relative positions of the gauge surfaces with respect to the centre of the front surface of the first gauge

TRAVELLING STANDARD : A 1020 mm long step gauge with 51 steps

The key comparison reference value, PTB, METAS, NMIJ and NIST, and then by fitting a linear regression to obtain the constant and proportional x_{Rc} parts such thatx_{Rp}, where x_{R} = x_{Rc} + x_{Rp} L is the interval length in mm. LThe combined standard uncertainty of is given by x_{R}u_{R} = u_{Rc} + u_{Rp}, as explained in Appendix B on page 32 of the Final Report.L |

Degrees of equivalence relative to the key comparison reference value have been analysed into constant and proportional D_{i}_{c} terms with expanded uncertainties (coverage factor D_{i}_{p}) k = 2 and U_{i}_{c}, for each laboratory U_{i}_{p}, as explained in Appendix B on pages 32 and 33 of the Final Report.i |

The pair-wise degrees of equivalence are not computed for this comparison. |

MEASURAND : Length between the ball centres of each ball bar

Ball bar material : 2 steel ball bars and one Super Invar ball bar.

NOMINAL VALUES : 400 mm and 800 mm for steel ball bars and 800 mm for Super Invar ball bar

For each ball bar , is obtained as the mean of all participants' values x_{Rk}. The standard uncertainty, x_{ik}, of key comparison reference value u_{Rk}, is obtained from the reported standard uncertainties x_{Rk}, as given in equation 6 on page 25 of the Final Report.u_{ik} |

The degree of equivalence of each laboratory is given by a pair of terms expressed in µm:kD_{ik}= and its expanded uncertainty x - _{ik}x_{Rk} (coverage factor 2) calculated from the equation 4 on page 16 of the Final Report.U_{ik} |

The pair-wise degrees of equivalence are not computed for this comparison. |

TRAVELLING STANDARD : A 1020 mm long step gauge with 51 steps

The participants' reported values and corresponding standard uncertainties are given in Tables 2 and 4 of the Final Report (page 13 and page 15, respectively), for the 51 steps.

For each laboratory * i*, a linear regression was fitted on the data, so the measurement of 51 gauge surfaces is analysed into constant

The measurement of laboratory

VNIIM and INRIM withdrew during the comparison.

NRC and CSIR-NML did not report any data due to technical problems.

CENAM realised a re-measure in 2002.

MEASURAND : Length between the ball centres of each ball bar

Ball bar material : 2 steel ball bars and one Super Invar ball bar

NOMINAL VALUES : 400 mm and 800 mm for steel ball bars and 800 mm for Super Invar ball bar

** x_{ik} **: result of measurement carried out by laboratory

VNIIM and INRIM withdrew during the comparison.

NRC and CSIR-NML did not report any data due to technical problems.

CEM, CENAM, and METAS did not participate in the ball bars comparison.

NMIJ and NMIA reported results only for steel ball bar with nominal length 400 mm.