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Calibration of depth setting standards


The calibration of depth setting standards is offered by numerous DAkkS accredited measurement laboratories. PTB calibrates depth setting standards only for DAkkS laboratories. A list of DAkkS accredited laboratories as of 12.2022 is attached here:

DAkkS-Labor Measure Range
Contact E-Mail
AmetekPt0,2 … 12
JenoptikPt und d0,2 ... 12Stefan Feifelstefan.feifel(at)jenoptik.com
Pt und d>12 … 5500
MahrPt und d0,2 ... 12Arne Deppedkd(at)mahr.com
MitutoyoPt und d0,2 ... 12Wilhelm Blumenscheinw.blumenschein(at)mitutoyo.de
QS-GrimmPt0,8 … 12
Saliger-GruppePt0,2 ... 12Dr. Ramon Watermannvame(at)saliger-gruppe.de
TrescalPt0,2 … 12
Pt12 ... 80

PTB calibration of depth setting standards

The calibration of the step and depth setting standards is carried out at PTB according to the specifications of ISO 5436. The measurements are carried out on the stylus instruments

  • MAHR LD 120 (for deep grooves up to 5000 µm),
    TENCOR P17 (grooves up to 900 µm) as well as the
    HRTS (all intermediate sizes up to 450 µm).

If no deviating specifications are required, the calibrations are carried out with three measuring passes and three cuts each at a distance of 1000 µm.

The number of measurement passes, number of cuts and their position are always listed in the calibration certificate.

For traceability of the calibration measurements, a reference standard with the same height steps is measured before and after the measurement of the standard to be calibrated. The reference standard has been calibrated beforehand with a traceable measuring system. These measurement steps are not necessary when measuring with the HRTS, as this measurement setup is already traceable in itself.

After the measurement, the step heights or groove depths must be calculated individually for each measuring section. For this purpose, the edges (E1, E2, E3 E4, see Fig. 2) must be determined. The edge finding is determined by a software algorithm in our measurements. Based on the edges found, the reference surfaces (A, B and C) can be determined for the respective section. The distance of the reference surfaces to the edges and their length is determined by ISO 5436. For deep grooves, the reference width w is placed in the groove base, for very shallow grooves or grooves with a round groove base, the reference width is half the groove depth. Another special case are very wide grooves etched in silicon. Here the reference width is so large that there is not enough space for the upper reference surfaces. In such cases, the upper reference surfaces are determined according to own specifications, deviating from ISO 5436. The determination of the reference areas is noted in the calibration certificate in all cases.

A regression line g is determined from the measured values of the reference areas A, B and C. The regression line g is, on the one hand, integrated as best as possible into the calibration curve. This is shifted into the reference areas A, B and C as best as possible. The distance of the two shifted, parallel straight lines through A and B as well as through C is the calculated groove depth d.

Fig. 2 Edges and reference surfaces in groove evaluation of deep grooves according to ISO 5436.