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Page 847 of 936 Results 8461 - 8470 of 9356

Ichiko Misumi, Satoshi Gonda, Osamu Sato, Kentaro Sugawara, Kazunori Yoshizaki, Qiangxian Huang, Tomizo Kurosawa, Toshiyuki Takatsuji
DESIGN AND FABRICATION OF NANOMETRIC LATERAL SCALE CONSISTING OF GaAs/InGaP SUPERLATTICE

Nanometric lateral scales with 25 nm pitch using GaAs/InGaP superlattice were designed and fabricated for realization of the-smallest-pitch-CRMs. The pitch of the scales was measured by a nanometrological AFM and uncertainty in pitch measurements was evaluated. The quality of the developed scales as CRMs was verified.

Cristian Fosalau, Emil Vremera, Marinel Temneanu, Mihai Cretu
USING THE GMI EFFECT FOR DETECTING SMALL ROTATIONAL MOVEMENTS

The paper goal is to describe the way in which the Giant Magnetoimpedance Effect (GMI) occurring in the magnetic amorphous wires can be utilized to detect small rotational movements. The operation principle is based on modification of the wire impedance under action of a torsional stress when an ac low current flows through it. The schematic overview of an angle sensor built around this effect, along with some experimental results obtained upon the functional model are presented in the paper. Analysis was performed on the sensor behavior under different frequencies and intensities of the current flowing through the wire as well as under different values of an axial dc magnetic field applied to the wire in order to control the angle span of the sensor.

Dariusz Janecki, Stanisław Adamczak, Marek Cabaj
DETERMINING THE CHARACTERISTICS OF SENSORS DISPLACEMENT IN INSTRUMENTS FOR ROUNDNESS MEASUREMENTS

In the paper "A new approach to the examination of the displacement sensor characteristics" published in Measurement, vol. 28, pp. 261-267, sebrowska-Lucyk proposes a new, interesting method for measuring the characteristics of displacement sensors. The method consist in exciting the sensor tip with a sinusoidal signal having a known amplitude. In this paper, the authors modify the method so that it is possible: (1) to conduct measurements by means of a typical sensor tip with a circular crosssection, (2) to eliminate the necessity of possessing an additional measuring eccentricity standard, (3) to determine the sensor characteristics on the basis of non-closed roundness profiles.

Antonio Piratelli-Filho, Geraldo G. Soares-Neto
ERROR EVALUATION OF SECONDARY FREE FORM SURFACES IN COMPLEX PART MEASUREMENT

The main purpose of this work is to investigate the errors on secondary surfaces generated to joint free form surfaces of complex parts measured with Coordinate Measuring Machines (CMM) and modeled with CAD techniques. The approach involves the measurement of a complex part and fitting using NURBS curves and surfaces. The errors were determined by difference between determined points on secondary surfaces and fitted CAD surface.

Kazuhiro Ishizu, Akihito Takahashi, Tomoyuki Miyazaki, Kentaro Nemoto
MINUTE FORM MEASURING SYSTEM

According to the progress of industrial products, high-accuracy and minute parts are increasing rapidly. As one of the desired measuring systems for accurately and efficiently evaluating the 3D form of these mass-production minute form parts, an evaluation system constructed by combining "a high-accuracy stage", "minute probes" and "an optical unit" is described.

Bartosz Gapinski, Miroslaw Grzelka, Miroslaw Rucki
SOME ASPECTS OF THE ROUNDNESS MEASUREMENT WITH CMM

In the article, the form deviation (roundness) measurement with the Coordinate Measuring Machine has been discussed. The influence of the measuring points number and the type of the roundness deviation on the result (since different fitting elements are used) has been presented. The obtained investigation results prove that minimal number of points is not enough for measurement, while the too large number does not improve the measurement, as well. The recommendation on the measuring points number have been given.

Sueli Fischer Beckert, Edson Pacheco Paladini
MEASUREMENT PROCESSES ANALYSIS WITH GRR OR EXPANDED UNCERTAINTY? APPLICATION OF CONFIDENCE LEVEL OF 99,73% OR 95,45%?

This paper demonstrates the application of the ISO GUM for analysis of the measurement processes used in the product control. It describes the attention in the method application and the need to establish the acceptability criterion for the measurement process. But also their advantages, such as, the identification of the existent uncertainty sources, the simplification through the sample selection and the application of a confidence level of 95,45%.

Tsukasa Watanabe, Hiroyuki Fujimoto
HIGH ACCURACY ANGLE INDEXING TABLE

National Metrology Institute of Japan studied the high precision angle indexing table. We used the principle that NPL reported the indexing accuracy 0.01" in 1984. We verified this principle using the angular primary standard of Japan and proved this principle can exceed 0.001" super-high angular precision.

Yukitoshi Ihara, Shozo Matsushita
MOTION ACCURCY MEASUREMENT DEVICE BY USING PARALLEL MECHANISM FOR MULTI-AXIS MACHINING CENTERS

The main purpose of this study is to develop a measuring device by parallel kinematics for measuring a motion accuracy of multi-axis machining centers. The initially developed measuring device had three displacement sensors and it could measure only position of the spindle because it had only 3 DOF. Optical linear encoders were used for the displacement detecting sensors, while the steel balls and permanent magnets were used for the joints of parallel mechanism. With the 3 DOF device the motion accuracy of machine tools with three-axis was measured. Since the mechanism of the joint was smooth and the sensor resolution was small enough, the measured result showed that the measuring device had an enough performance for the machining centers in normal accuracy. Then the 6 DOF measuring device was developed. It had six displacement censors and it could measure both position and posture angle of the main spindle. In spite of the adoption of parallel kinematics, the forward kinematics calculation was possible due to the sophisticated arrangement of sensors, thus the hi-speed data acquisition could be possible.

Vedran Mudronja, Sanjin Mahović, Biserka Runje, Srđan Medić, Gorana BarÅ¡ić
EXAMPLE OF CALCULATING CORRECTIONS AND MEASUREMENT UNCERTAINTY IN THE PROCEDURE OF MEASURING SPHERES

Metrology practice confirms that very often by carrying out the corrections the result of measurement may contain greater error (deviation) than in the case of no corrections at all. Therefore, it is often assumed that the value of correction is zero, with assumed influences on the uncertainty of correction included in the uncertainty of the measuring results. In the field of length metrology the correction cannot be avoided in case of temperature influences or actions of the measuring force during the measurement procedure. Numerous experiences show that temperature correction is a questionable procedure due to a whole number of unknowns, and in case of more demanding measurements and the related more demanding uncertainties of measurement, one resorts to achieving of standard temperature conditions. However, the measurement results have to be corrected in case of the action of the measurement force, especially because the value of correction often exceeds the value of uncertainty of measurement. An example of measuring the sphere diameter, described in this work, fully supports the mentioned claim.

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