Jon R. Pratt, David B. Newell, John A. Kramar
The NIST electrostatic force balance compares mechanical probe forces to an SI realization of force derived from measurements of the capacitance gradient and voltage in an electronic null balance. As we approach the nanonewton regime, the finite stiffness of the guiding flexure in the balance becomes a limiting factor. Here, we consider an equal arm balance mechanism constructed using flexure pivots as an alternative to the compound rectilinear spring of the present design. We review how the sensitivity of such mechanisms can be adjusted either by manipulating the center of gravity, or by...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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John A. Kramar, David B. Newell, Jon R. Pratt
We have designed and built a prototype electrostatic force balance for realizing forces in the micronewton range. The active electrodes are concentric cylinders, the outer serving as the reference and the inner suspended and guided by a rectilinear flexure mechanism. The geometry has been designed such that a near-linear capacitance gradient of 1 pF/mm is achieved at a working overlap of 5 mm. We have used this balance in a null-displacement mode to compare an electric realization of force with the force generated by calibrated deadweights of nominal mass 1 mg, 10 mg, and 20 mg. The...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Douglas T. Smith, Shane Woody, Jon R. Pratt
The loading mechanisms of instrumented indentation machines are often calibrated using deadweights. In many cases, due to the geometry of the loading frame, the applied deadweight is tensile, while the indentation loads to be measured are compressive. In this paper, we report preliminary efforts to develop a compressive load cell for use on a typical instrumented indentation machine. Two devices were evaluated, one a compact capacitance-based device (fabricated at the National Institute of Standards and Technology), the other a piezoresistive force sensor. We will describe the calibration...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Günter Doemens, Dieter Spriegel, Hans Wünsche
In the fields of automation, drives and production engineering the measurement of force and torque is of particular importance for the monitoring and control of industrial processes. Today’s sensors applied for this purpose are mostly based on strain gauges with a limited range of applications. Reasons therefore are rooted in the short duty cycle, the poor overload safety and the complex mounting. In order to avoid the disadvantages mentioned an innovative micro-system based capacitive force and torque sensor has been developed. By attachment at two distinguished points the sensor is...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Thomas Allgeier, Helmut Gassmann, Ulrich Kolwinski, Peter Giesecke
This paper introduces the requirements and possibilities of simultaneous force and moment measurements in industrial testing. Apart from describing the principal mechanics of force and moment vectors, important implications of ignoring disturbing components are mentioned. This is followed by an overview of practical applications of multicomponent measurements. The main part of the paper describes a new measurement tool for the data acquisition, evaluation and vector analysis. This comprises issues of transducer selection and applicability, details of the electronics used and also addresses...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Thomas Allgeier, Ulrich Kolwinski, Daniel Schwind
This paper describes a new type of standard machine, based on a travelling (jockey) weight moving along a lever which is supported on strain-controlled elastic hinges. It is equally applicable to the quantities force and torque. In addition to step-by step loading, the machine can perform continuous calibrations without having to rely on a reference transducer. Furthermore, testing through the zero load condition is possible with suitable mounting components. In the case of force machines, the jockey-weight design allows to tare the weight of all load introduction components, so that loads...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Udo Milz
We present new, weighing sensors with integrated electronics, specially optimized for dynamic weighing and dosing. There is already extensive signal processing in the transducer, with all the necessary functions for fast weight value acquisition and for full, local dosing control.
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Reinhold Vollmert, Günther Ramm
Strain gauges allow the measurands force, pressure, torque or strain to be converted into voltage ratios and to be indicated by measuring amplifiers. Precision measurements are preferably carried out at 225 Hz and at voltage ratios of up to 2 mV/V. Bridge standards, which have to be traced back to national standards, are used for the electrical calibration of these measuring amplifiers. More than 15 years ago, in PTB the first measuring arrangement for this purpose has been developed and installed. The present contribution explains the traceability principle of bridge standards, shows the...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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Oliver Mack
For the measurement of the physical quantity force with conventional transducers it is assumed that the preferred direction of the force transducer is the same as that of the vector of the force. In practice this case is rarely being observed. Due to insufficient alignment of the transducer or of the measurement facility mechanically disturbing components such as bending moments, shear forces or additional axial forces occur which may influence the measurement result significantly. This paper deals with the investigation of the influence of static mechanical disturbing components on a...
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
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D. Ratschko, C. Schlegel, F. Scholz, M. Gläser
An analysis of an ion beam produced through sputtering of gold by means of Xenon ions in a CHORDIS ion source was performed. The composition of the extracted ion beam was investigated via mass spectroscopy using a double focussing dipole magnet. From the high resolution mass spectrum the abundance pattern of stable Xe isotopes was varified and the amount of charge transitions from 2+ → 1+ could be estimated. A maximum gold current of 0,8 mA directly behind the ion source was measured.
Joint International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the age of globalization
· TC3
· 2002
· Download