A table-top version of a Kibble balance called Planck-Balance 1 (PB1) has been developed in a collaboration between the Physikalisch-Technische Bundesanstalt and the Technische Universität Ilmenau. It is aimed for calibrating E1 mass standards for a mass range from 1 mg to 1 kg. This paper gives a brief overview of the concept of the PB1, its measurement setup, and some initial measurements of the force mode and the velocity mode.

In a forecast of the revised international system of units, that will come into force on 20th May 2019, the Physikalisch-Technische Bundesanstalt is developing and establishing a strategic concept, that allows the kilogram to be realized and distributed on the basis of new artefacts and methods. Possible paths of the quantum-based kilogram from its definition based on the Planck constant to the macroscopic world are being elucidated, i.e. the use of silicon spheres of different qualities as well as the use of Kibble-Balances and new developments of table-top weighing instruments. Beside metrological aims the availability of realizations and easy handling procedures are of crucial importance within a future dissemination chain. Advantages and disadvantages of different approaches are being examined and current developments, basically on the silicon route, and their expected measurement uncertainty are outlined. Scientific and strategic developments in the use of silicon spheres in the future mass dissemination chain are accompanied by more than 20 national metrological institutes and designated institutes by testing the existing methods and doing their own investigations.

A table top version of a Kibble balance called the Planck-Balance has been developed by the Physikalisch-Technische Bundesanstalt (PTB) and the Technische Universitat Ilmenau (TUIL). After one year of development, the first measurement results were obtained. The mass of a 10 g mass standard has been determined with a relative type A uncertainty of 3 × 10 -7 . A preliminary uncertainty budget shows a relative combined measurement uncertainty of 1 × 10 -6 . This paper gives a brief overview of the concept of the balance, its measurement principle, its results and a preliminary uncertainty budget.

A balance is proposed, which allows the calibration of weights in a continuous range from 1 mg to 1 kg using a fixed value of the Planck constant, h. This so-called Planck-Balance (PB) uses the physical approach of Kibble balances that allow the Planck constant to be derived from the mass. Using the PB no calibrated mass standards are required during weighing processes any longer, because all measurements are traceable via the electrical quantities to the Planck constant, and to the meter and the second. This allows a new approach of balance types after the expected redefinition of the SI-units by the end of 2018. In contrast to many scientific oriented developments, the PB is focused on robust and daily use. Therefore, two balances will be developed, PB2 and PB1, which will allow relative measurement uncertainties comparable to the accuracies of class E2 and E1 weights, respectively, as specified in OIML R 111-1. The balances will be developed in a cooperation of the Physikalisch-Technische Bundesanstalt (PTB) and the Technische Universitat Ilmenau in a project funded by the German Federal Ministry of Education and Research.

The field of Large-Scale Metrology has been studied extensively for many decades and represents the combination and competition of topics as diverse as geodesy and laboratory calibration. A primary reason that Large-Scale Metrology continues to represent the research frontier is that technological advances introduced and perfected at a conventional scale face additional challenges which increase non-linearly with size. This necessitates new ways of considering the entire measuring process, resulting in the application of concepts such as virtual measuring processes and cyber-physical systems. This paper reports on the continuing evolution of Large-Scale Metrology.

Today, almost all measuring systems involve computation and it is important that software components can be shown to be operating correctly. The European Metrology Research Programme Joint Research Project (JRP) NEW06 "Traceability for computationally-intensive metrology" is specifically concerned with developing technology that will deliver such traceability. This paper provides a broad overview of the main activity being undertaken within the JRP. An ultimate goal of the JRP is to establish an information and communications infrastructure for software validation. The steps required to reach this goal are described.

Computational software used in metrology can be validated online at the point of use based on test data and associated reference results. Since modern metrological applications often use complex algorithms for calculating results, it is very import that all computational links are recognized explicitly and are known to be operating correctly. In order to establish traceability to national standards also in metrological computation, the European project EMRP NEW06 TraCIM was launched by the EC and the European metrology association EURAMET. An example from the field of coordinate metrology is used to explain the basic concept: the validation of least squares fitting algorithms for regular features such as cylinders, cones, planes or spheres via the Internet by means of the TraCIM system.

In this paper we propose a way to parametrize certain geometrical elements such as lines, planes or cones, and define distance functions between the respective parameters. These functions are used as test values for the validation of Gaussian best-fit software. Furthermore we describe the concept of reference pairs used for the test and show how one can calculate the numerical uncertainty for these reference pairs applying a Monte-Carlo simulation.

Three-dimensional micro probing systems based on silicon force sensors allow force measurements in the range of several μN. Their high sensitivity enables tactile measurements of three-dimensional micro- and nanostructures without leaving strong traces on the probed surfaces. However, their small sizes of 6.5 mm × 6.5 mm do not allow an easy handling and can lead to a breakage of the complete system rapidly. To improve the handling and the integration of these micro probing systems a new kind of probe head and an appropriate assembling method have been developed. In order to show the performance and the high reproducibility of microprobes for their use in coordinate metrology, many measurements have been carried out with a customary gear measuring instrument on a calibrated spur gear. The results have been compared to calibration values and the deviations are in the range of maximum some 100 nm.

Micro gears are applied in an increasing quantity in many applications. Therefore, precise measurements are of growing importance to ensure their quality. This contribution describes the measurement of gears of a micro planetary gear set with a tactile probe, a tactile-optical probe, an optical sensor, and computed tomography (CT).For the tactile measurements, a high precision piezoresistive microprobe was used. A so-called fiber probe was applied for tactile-optical measurements. This probe applies image processing to determine the position of the tactile probing element. For all tactile and tactile-optical measurements, single point probing was used. The optical measurements were carried out with an imaging sensor based on focus variation. Due to limited accessibility, on some gears not all regions could be measured by the optical sensor and the tactile-optical probe. In contrast to this, with CT the whole part could be measured with high point density. We used a micro-CT system and carried out measurements with Synchrotron-CT.All the sensors used deliver measurement data in Cartesian coordinates. It is a challenge to transfer these data into coordinates in which gear parameters are defined. For this, special attention must be paid to the determination of the gear axis and to the orientation of the teeth.The applied procedures are detailed for different micro gears. The comparison between data of different measurements was carried out successfully. The deviations between the CT data and the tactile or tactile-optical data lie in the range of only a few micrometers.

The paper describes the manufacturing and dimensional measurements of high precision work-pieces by PTB, which shall act as test masses (TM) for the satellite-based experiment MICROSCOPE. The manufacturing involves turning of Ti alloys and PtRh10. The measurements were made by in-process tactile probing, coordinate metrology, and form measurement. The high geometrical demands of the project could be fulfilled on both the manufacturing and the measurement sub-projects.

The accuracy of coordinate measuring machines (CMMs) strongly depends on geometrical errors that effect the measurements. Several methods for mapping these errors have been developed and some have been im- plemented. Examples are the direct measurement analysis by means of interferometers, straight edges, squareness stan- dards or the analysis by application of artefacts like ball or hole plates or by using the multilateration approach using high accurate tracking laser interferometers. In this paper a comparison between the well established ball or hole plate method against the new multilateration approach will be presented and discussed. The measurements were carried out on a high accurate and commercial CMM at the Physikalisch - Technische Bundesanstalt (PTB) in coopera- tion with the National Institute for Standards in Egypt (NIS). For error mapping a ceramic hole plate 960 mm x 960 mm with a grid spacing of 60 mm and a commercial Laser Tracer (LT) were used. Both were originally developed at PTB. The result of the comparison shows that the differences between all estimated rotational axis errors are within 1 arc second. The differences of most of the trans- latorical errors are less than 1 micrometer. Consequently, both error mapping methods can be used alternatively. Moreover, the paper will show that the multilateration ap- proach can cover a long range of the working volume of machines, is easy for handling, and reduces the time of measurements.