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One-dimensional grating standards with sub-hundred nanometre pitches are required for calibration of nanometrological instruments. Nanometric lateral scales (design pitches: 100, 60 and 50 nm) for the calibration of nanometrological instruments were designed and fabricated by electron beam cell projection lithography. An offset-locked laser system consisting of an I2-stabilized He–Ne laser and a slave laser was installed in an atomic force microscope with differential laser interferometers (DLI-AFM) for the realization of a continuously, directly length-standard-traceable system and the pitches of the lateral scales were calibrated using the new DLI-AFM. The average pitches were quite close to the design pitches and the expanded uncertainties (k = 2) were less than 0.6% of the design pitches. The developed nanometric lateral scales are of sufficiently high quality and are candidates for certified reference materials (CRMs).

Industrial x-ray computed tomography (CT) is a well-established non-destructive testing (NDT) technology and has been in use for decades. Moreover, CT has also started to become an important technology for dimensional metrology. But the requirements on dimensional CTs, i.e., on performing coordinate measurements with CT, are different from NDT. For dimensional measurements, the position of interfaces or surfaces is of importance, while this is often less critical in NDT. Standardization plays an important role here as it can create trust in new measurement technologies as is the case for dimensional CT. At the international standardization level, the ISO TC 213 WG 10 is working on specifications for dimensional CT. This paper highlights the demands on international standards in the field of dimensional CT and describes the current developments from the viewpoint of representatives of national and international standardization committees. Key aspects of the discussion are the material influence on the length measurement error E and how E can best be measured. A respective study was performed on hole plates as new reference standards for error testing of length measurements incorporating the material influence. We performed corresponding measurement data analysis and present a further elaborated hole plate design. The authors also comment on different approaches currently pursued and give an outlook on upcoming developments as far as they can be foreseen.

a b s t r a c tA tracking interferometer is a laser interferometer with the mechanism to steer the laser direction to automatically follow a target retroreflector. This paper experimentally investigates the performance of the tracking interferometer prototype, developed by a part of the authors, in estimating the volumetric accuracy of a machining center based on the multilateration principle. Then, the prototype's technical issues are discussed based on the measurement uncertainty analysis. This paper briefly reviews the direct algorithm to calculate the three-dimensional position of the target, as well as the indirect algorithm to estimate geometric error parameters of the machine's kinematic model. Their comparison is also presented based on the uncertainty analysis.

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The vibration and noise of gears is one of the serious problems for devices, such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are considerably affected by the tooth flank form deviation of micrometer order. The quality of product gears is controlled using a gear measuring instrument and calibrated with an involute artifact. However, the conventional calibration of the involute artifact cannot achieve a sufficient accuracy. In this report, a direct method of measuring the involute artifact using a laser interferometer is proposed. Fundamental experiments are carried out, in which the effects of the surface condition of the measured object and the effect of the driving of the artifact are investigated. It is confirmed that the proposed method enables the measurement of the detailed form of an involute tooth flank and has the potential of accomplishing a highly precise measurement of an involute artifact.

and two-dimensional (2D) gratings are some of the most important transfer standards for the calibration of nanometrological instruments. National Metrology Institutes (NMIs) demonstrate their calibration capability through international comparisons among themselves and provide pitch calibration services for their customers. In the past, international comparisons were performed three times for gratings with large pitches such as 4000 nm, 1000 nm, 700 nm and 300 nm. Additionally, a bilateral comparison was conducted for 100 nm and 50 nm between the Japanese National Metrology Institute (NMIJ) and the German National Metrology Institute (PTB). The industry, however, requires calibration services for increasingly smaller pitches. In a previous study, NMIJ developed a nanometric lateral scale, a special 1D grating with 25 nm pitch consisting of Si/SiO 2 multilayer thin-film structures, and calibrated the pitch of this scale by using the NMIJ's atomic force microscope equipped with differential laser interferometers (DLI-AFM). In this paper, we will report results of an informal bilateral comparison for the nanometric lateral scale between NMIJ and PTB.