**4. Conclusions**

48 Modern Metrology Concerns

Fig. 9. Calibration results on Zerodur scale, 200 mm graduation, 1 mm step.

Fig. 10. Comparison of long line scale calibration capabilities

conditions in the laboratory.

It has been demonstrated that the capabilities of a newly developed comparator are close to the calibration capabilities of analogous long scale calibration systems in the other countries, available from BIPM key comparison database, see Fig. 10, and still can be improved first of all by embedding an automatic line focusing system and tightening tolerances of ambient Precision measurements based on the length standard are very important, and their significance is growing with the advancement of science and industrial technology. Particularly important is product quality improvement in production processes. The development of metrology standards follows the needs of technology.

Diversity of tools and measurement techniques in dimensional metrology require significantly more mature set of standards for characterization of the measurement process used to obtain measurement data, e.g. what sampling strategy was used, what filtering was applied and what measurands definition was applied. It will also expect more know-how on the user level of the metrology involved in operating modern measurement equipment.

In industrial metrology, several issues beyond accuracy constrain the usability of metrology methods. These include, among other factors, the speed with which measurements can be accomplished on parts or surfaces in the process of manufacturing, and the ability of the measurement system to operate reliably in a manufacturing plant environment considering temperature, vibration, dust, and a host of other potential hostile factors.

The relevance and necessity of addressing the problem of precision and high-speed line scale calibration is primarily driven by the rapid increase of demands on calibration efficiency of precision scales. Considerably higher precision and efficiency requirements are set for new systems, besides, it is aimed at traceability of precision line scale parameters during manufacturing process in the technological line, and calibration process should be as short as possible.

This chapter comprehends a synopsis and analysis of literature and existing scientific and technical solutions of precision 1D length calibration. It addresses also the problems of the research and development of an interferometer-controlled comparator that is operated in non-ideal environmental conditions and enables to trace the calibration of line scale of up to L ≤ 3.5 m long to the wavelength standard.

The analysis and research results represent both systematic methodology and knowledge base for evaluation the length calibration accuracy that involve current and new technologies, and can be applied gradually in various precision machinery and instrumentation.
