Richard Davis
MAGNETIZATION OF MASS STANDARDS AS DETERMINED BY GAUSSMETERS, MAGNETOMETERS AND SUSCEPTOMETERS

Magnetization of a mass standard can lead to weighing errors. This is because most modern balances are sources of non-uniform magnetic induction. Although the problem of unwanted magnetic forces is well known, the characterization of the magnetic properties of mass standards and balances can be problematic. This paper compares the kind of information that can be obtained from three types of instruments: Hall-probe gaussmeter, fluxgate magnetometer and susceptometer.

Werner Brenner, Franz Suemecz, Aleksandar Vujanic
PRINCIPLES OF MICRO TORQUE MEASUREMENT - AN OVERVIEW

This paper gives an overview of rotating microsystems including the entire spectrum of dimensions from the sub-millimeter range to sizes of a few millimeters. Principles and instrumentation for micro torque measurement are described.

Dae-Im Kang, Hou-Keun Song, Jeong-Tae Lee, You-Kyu Park, Jong-Ho Kim
TRACEABILITY OF LARGE FORCE STANDARDS IN KOREA

This paper describes traceability of large force standards up to 30 MN in Korea. 15 material testing machines of each having more than 10 MN capacity in industrial companies have been used for evaluating performances of mechanical components such as a pot bearing or an elastic bearing which is one of the important components in bridges. We have 10 MN force standard machine with relative uncertainty of 5·10^-4 (k = 2). We designed build-up force measuring systems of having 30 MN capacity to be used in calibrating material testing machines above 10 MN capacity. We have evaluated uncertainty budgets of build-up systems. Also, this paper summarizes calibration results of a material testing machine of 30 MN in Korea.

Gerd Jäger, Roland Füßl
INTERFERENCE-OPTICAL FORCE SENSOR FOR SMALL FORCES

Force measurement at a resolution in the micronewton range is advantageously performed by means of electromagnetic force compensation. So far, weighing systems of this kind have been working only in a horizontal position. Although resistance strain gauge force sensors are suited to various force directions, they cannot be used for precision measurements in the micronewton range.
In this paper, an interference-optical force (IOF) sensor is described which can be used both for horizontal and vertical force measurement. The force measuring range of a specially designed force sensor amounts to 100 mN (10 g), resolution to 0.01 mN, and the extended measuring uncertainty to 0.008 mN for k = 2. The structure, the operating principle and the signal processing of the force sensor are described and, furthermore, a uncertainty of measurement analysis of the entire system is made. The successful application of the interference-optical force sensor is finally demonstrated by means of the example of the calibration of applanation tonometers.

C. Ferrero, C. Marinari, E. Martino
DEVELOPMENT AND METROLOGICAL CHARACTERISATION OF A BUILD-UP FORCE STANDARD UP TO 3 MN

The establishment of national calibration services (NCS) and mutual agreements between the NCS of the different countries (UKAS, DKD, SIT, etc.) have increased the necessity of the dissemination of the unit of force inside the individual countries and of standards harmonisation through continuous international comparison. In the paper the development, construction and preliminary metrological characterization of a Build-Up System (Force Transducers Pyramid Type) are described. In its construction three force transducers, in the nominal range of 1000 kN were used, individually calibrated and later together. Results are given concerning: the evaluation of repeatability, linearity, rotation effect and hysteresis.