In this paper a calibration technique for the error mapping of a 2D sensor - a cross-grid encoder – is presented. A reversal technique to assess the squareness errors is used. The calibration set up includes a metrology frame made of Zerodur®, a very low coefficient thermal expansion material in order to reduce thermal errors. Additionally, an analysis by means of finite element method is carried out for an adequate design of the set up. Finally, the uncertainty values for the 2D cross-grid encoder system are calculated.

This paper presents the role played by multilateration when laser trackers (LTs) are used in volumetric verification of long range machine tools.
A comprehensive study on the influence of LTs positioning has been done. The parameters taken into account during the positioning of the LTs are: the viewing angle, the distance to the work space and the LT measurement errors.
Also, different self-calibration techniques for calculating the LTs positioning are explained in order to show their influence in the correction improvement using multilateration techniques.
Finally, it is shown how obtained results improve the effectiveness of this procedure in terms of the final error correction when LTs are used in long range machine tool volumetric verification.

A high-frequency part of repetition frequency modes of mode-locked fiber laser is selected by a tandem Fabry–Pérot etalon. The 3-GHz repetition-modified laser is transmitted to a Michelson interferometer. The interference fringes generated have a temporal coherence pattern and can make positioning in space. The optical system of the interferometer is designed as double-path beams. A center between two beams is located at the position of a measuring probe of CMM. Using this design, we can apply the modelocked fiber laser to artifacts following contact method. The advantage of the contact method can measure variety-shape artifacts, i.e. step gauge etc, that non-contact method cannot be used.

Coordinate Measuring Machine (CMM) is often used for geometrical measurement due to its precision and general versatility. Recently the case that the CMM is placed in production line environment, is increasing. There are a lot of factors which make precision of measurement worse, like dust, thermal fluctuation, a physical collision and so on. To check these influences to precision of measurement, daily inspection of CMM is necessary. In previous research, the method of daily inspection of CMM was proposed. The result of inspection by two artifacts with different ball layout is shown.

As an alternative to the conventional method, which length measurement is performed as a function of the wavelength of a monochromatic laser source, we proposed the method of measuring arbitrary and absolute length using the pulse repetition interval of a femtosecond optical frequency comb (FOFC - the national standard tool for measuring length in Japan). A helium-neon laser evaluation system was developed for distance determination comparison experiment and its uncertainty estimation was performed in order to validate the proposed method.