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.
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...
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....
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.
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.
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...
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.
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...
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.
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.