For the precise and accurate measurement of surface topography a whole range of surface detection systems is available. With their application in research and production problems arise due to the lack of traceable standard artefacts for the instrument calibration in X, Y and Z directions and for the calibration of filters. Existing ISO standards on calibration specimens are inadequate and limited in that they only cover contacting instruments and only partially the measuring ranges for these instruments. The whole range of non-contacting instruments are not covered despite their increasing use in industries ranging from automotive manufacture to ultraprecision manufacture of data storage systems and compact discs.
The project is concerned with developing calibration standards including their production methods and calibration procedures as a consistent means of calibrating different types of instruments that report microtopography information about engineering surfaces across the whole range of characteristic dimensions.
The work programme consists of the following work packages:
- Design of calibration artefacts.
- Design and laboratory set-up of an active calibrator device.
- Development of production methods and investigation of limits of the processes for producing primary standards.
- Development of reproduction processes and investigations of the reproduction limitations of the replication methods.
- Development of calibration procedures for calibration specimens and instruments.
- Development of non-invasive cleaning, sealing and packaging methods for surfaces of calibration standards.
A survey report in German and a short version in English on the state of art of calibration standards are available. The design of calibration standards comprises the overall geometry of basic bodies for compression and injection moulding of plastic negatives with different step height, sinusoidal-, triangular and arcuate profiles covering Pt-values from 0.05 µm up to 100 µm and PSm values from 0.8 µm up to 800 µm. For active calibration in Z-direction a small size vertical calibrator has been designed, built and tested. Primary calibration standards have been produced by ion-beam and plasma etching (step height standards), by holographic generation of sinusoidal structures with two-beam interference exposure and by ultra-precision diamond cutting. From primary standards compression and injection moulded plastic negatives and Ni-negatives have been made from which again Ni-positives were produced. The replication processes showed negligible deviations from the Pt and Pa values compared to the primary standards. An important prerequisite is the cleanliness of the surfaces to be replicated during all stages of the replication processes. Procedures for cleaning glass, PVC, PC, PMM and Ni-surfaces have been developed and tested.
Calibration procedures for calibration standards and for calibrating instruments in X-, Y- and Z-direction have been developed and tested. Proposals for standardization of calibration standards and calibration procedures were derived from the results of the project.