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Page 598 of 977 Results 5971 - 5980 of 9762

W. Lotze, U. Lunze
TOLERANCE-FIT OF GEOMETRIC ELEMENTS AND SCULPTURED SURFACES AND PROFILES

For quality control in the case of workpieces measured by CMM both a sufficient number and location of measuring points and the correct evaluation for determining the minimum deviations of size, position and form for the entire workpiece guaranties economic manufacturing. The idea to fulfil this general objective function opens a new set of tasks besides of the well known data fitting for individual features. The paper deals with new solutions for data fitting of compound features with partly different tolerances oriented on the minimum zone objective function.

J. Leopold, H. Günther
NEW DEVELOPMENTS IN FAST 3D - SURFACE QUALITY CONTROL

Inspection is the process of determining if a product deviates from a given set of specifications. Fast Inspection usually involves measurement of specific part features such as assembly integrity, geometric dimensions and surface finish. It is a quality control task, but is distinguished from testing tasks. The visual inspection of 3D - parts (car body parts) is a special task within manufacturing that has been auto-mated at a comparatively slow pace up to this time. Different optical methods, applied for 3D - Measuring of microscopically and macroscopically sheet metal parts based on the Projected Fringes Method (PFM), the Electronic Speckle Interferometry (ESPI), the Structured-Lighting Reflection Technique (SLRT), White-Light-Interferometry (WLI) and also SEM-, AFM- and Laser Scanning methods (LSM) will be discussed. In addition, stylus instruments and also colorimeter measurements was included. The presentation is closed with advantages and disadvantages of different contemporary intelligent methods for car body inspections: Neural Net based Classification; Fractal Analysis and Wavelet Transformation.

K. I. Kutchinsky, S. V. Plotnikov, S. P. Yunoshev
SMART AND FLEXIBLE DIMENSIONAL INSPECTION

One of the important requirement for the smart automatic dimensional inspection systems is the operative widening of the inspected object nomenclature. The flexible technology of dimensional inspection, which allows to satisfy this demand, is suggested. This technology is based on the description of the inspected object as a combination of the basic elements – primitives. Such description can be automatically obtained from the object drawing, performed by means of the automatic design program (e.g. AutoCAD), according to certain rules of indication of inspected parameters and tolerances. Then formed description is used to produce an inspection strategy (including creation of the number, position and order of shadow projections on the various object fragments) at the stage of automatically translation the object drawing into its description file in the internal system format. Proposed technology was successfully applied to the optico-electronic systems for measurement of geometrical parameters.

M. Krystek, P.J. Scott, V. Srinivasan
DISCRETE LINEAR FILTERS FOR METROLOGY

Linear filters are used quite extensively in the field of dimensional metrology and surface texture for smoothing data collected from measurements. Past application of linear filters was largely limited to the Gaussian and 2RC filters. But recent advances in spline and wavelet theories have opened the way for more flexible and powerful linear filters that are getting more attention in industry. This paper describes these advances in linear filters and how they are influencing the development of ISO filter standards.

H. Korzeniewski, J. Jamiñski
ESTIMATION OF EPICYCLOIDAL GEAR CONTOUR

There are described guidelines of creating epicycloids and their application in engineering. Authors propose a scanning method as a way of estimation of real deviation of contour for epicycloidal gears. Measuring results and their interpretation is presented as well.

J. Kato, I. Yamaguchi
PHASE-DETECTION WAVELENGTH-SCANNING INTERFEROMETRY

We have realized an accurate height measurement for discontinuous shape by using the wavelength scanning interferometry combined with phase-shifting technique. It is based on detection of phase variation slope along the wavenumber axis at each pixel of a CCD camera that takes a number of phase-shifted interferograms using a PZT mirror. By using a tunable laser diode with wavelengthscanning range of 8 nm and scanning step of 0.2 nm, a height standard deviation of 40 nm could be obtained for the depth of ± 0.75 mm. This technique was applied to profile measurements of an aspherical mirror and rough-surface objects.

I. Kamigaki, 0. Yamakawa, Y. Omori T. Yamagiwa, H. Sakai
ROUNDNESS MEASUREMENT AND ITS UNCERTAINTY IN AN INTERNATIONAL COMPARISON

A highly accurate roundness measuring instrument and the calibration system of its probe were developed. The international round robin comparison of form measurement organized by the CIRP was carried out from 1996 to 1998. The measuring results obtained by using this instrument and system correspond satisfactory to the results by PTB with very small measurement uncertainty. For example, the obtained roundness of zerodur sphere with 50 mm diameter is about 179 nm with 9 nm (k = 2) in uncertainty of measurement, while the corresponding result by PTB is 184 nm and 10 nm respectively.

R. Jäger, P. Becker, N. M. Durakbasa, U. Kuetgens. P. H. Osanna, E. Seidl, M. Zawisky
OPTIMIZING PERFORMANCE OF NEUTRON INTERFEROMETERS

The perfect crystal neutron interferometer is an extremely sensitive device for verifying new concepts in quantum theory, the precise measurement of nuclear constants and non-destructive material analysis. The performance of such interferometers is strongly deteriorated in case of geometric imperfection. We at the Atominstitut of the Austrian Universities prepare the worldwide largest interferometers with lengths up to 21 cm cut from 4 inch monolithic perfect single crystal silicon ingots. The precision requirements are so demanding that we cannot rely on the precision of the cutting machines which is several microns for large crystals. Therefore we have developed an iterative procedure of precise determination and correction of geometric imperfections in the sub-micron range accompanied by numeric simulations of the fringe visibility. We will present improvements in interferometer quality using precise geometric measurements, numerical simulations and selective etching.

D. Janecki, S. Adamczak
LEAST-SQUARES VERSUS MINIMUM-ZONE FORM DEVIATIONS

This work deals with theoretical research into the occurrence of maximum differences between form deviations obtained for two types of reference profiles - least squares profile and minimum zone profile. The investigations concerned roundness, sphereness, (two- and three-dimensional) straightness, flatness and cylindricity profiles. Examples of interrupted and filtered profiles were also analysed.

D. Indof, S. Mahovic
2D AND 3D APPROACH TO MEASURING ROUGHNESS PARAMETERS

Contrary to the previous requirement to only monitor the changes, the need to understand the nature of the surface structure is more and more emphasised nowadays. There is already the possibility for 3D measurements, to a great extent owing to the development of electronics and computers. The contribution of this paper is in the analysis of the assessment of roughness using classical roughness parameters applied to 3D surfaces and an attempt to define the new parameters that would provide a more complete assessment of roughness with relation to the functional requirements met by the surface.

Page 598 of 977 Results 5971 - 5980 of 9762