The paper deals with the Fourier spectrum of nominally round profiles measured by the radius method. It is shown that amplitudes and phases of individual harmonics found by this method depend on the distance between the geometric centre of the investigated cross-section of the specimen under measurement and the centre of rotation as well as of the position of the sensor. On the grounds of a theoretical analysis, mathematical relations that describe the phenomenon of modulation of profile’s harmonics has been worked out. The paper describes conditions under which the eccentricity of a...
The calibration of the stylus type surface texture measuring instruments is usually carried out using a precision reference specimen of regular or random pattern of irregularities. These precision specimens are produced with hardened surfaces in order to minimize the scratching effect of the stylus on their certified values. The continual tracing on these surfaces is expected to deteriorate their quality. An experimental investigation on one of these specimens having a sinusoidal pattern of irregularity has been carried out. The specimen was traced several times on exactly the same position....
The method and the computerised set-up for the accuracy of touch trigger probe testing, outside CMM is discussed. A high resolution interference displacement transducer with a low measuring force is applied. The results of preliminary tests of TP2-5W and TP6 (Renishaw) probe in XYZ space are shown. The metrological characteristics of the probe are analysed.
In the paper the authors presented a comparison analysis of three different probes used for surface topography measurement. Skid and skidless stylus probes were used as contact pick-ups, while an optical autofocussing pick-up was applied as a non-contact one. The analysis was performed using several different topography parameters. It showed that a skid causes some relatively small distortions as far as the surface representation is concerned. The optical probe on the other hand proved to be a very difficult measuring tool, particularly for surfaces with steep slopes and sharp edges. Yet...
The role of surface metrology with respect to manufacture and performance is explained. How the rule has changed over the years and how it is likely to develop is discussed. It is shown how the classification of workpiece performance is related to surface typology and manufacturing control.
The aim of a high precision measurement room is to minimize most of the disturbing influences on the measuring devices installed in the measurement room by structural organization. The goal of scientific research in the field of manufacturing metrology is in particular the improvement of the measurement accuracy in the micro- and sub-micrometer range with simultaneously desired automation of the measurement procedures. In each case, reliable results must be obtained according to the internationally defined units for the success of the research work and for the acknowledgement of the results...
Interferometric length measurements without parallax error, based on the phenomenon of the reproducible wringing, are demonstrated. Using reproducible wringing together with the slave-block technique, accuracy level below 1 nm can be obtained for blocks of a few mm length with small flatness deviation. Phase change correction determination with sub-nm uncertainty is achieved for blocks up to 100 mm. Comparing the results of the double-ended method on a transparent reference plate with the reproducible wringing results, measurements without parallax error can be performed in the general case...
For the past four years, a group of international experts in the International Organization for Standardization (ISO) has been working on a series of standards for geometrical filters. This effort was motivated by an urgent need in industry to define the terms, concepts, and techniques involved in reducing raw data collected by measurements for proper interpretation while inspecting manufactured parts to verify whether they meet their tolerance specifications. This paper describes the efforts of this ISO group and what has been accomplished thus far.
In this paper, profiles along concentric circles on two precise mirrors are measured by using a Fizeau-interferometer with no standard. For the measurements, spacing between the two flat mirrors is measured with the interferometer at the angles of every 5 degrees along the circles. With these data, profiles are calculated using the Fourier transformation method and linear equation method. Profiles along ten concentric circles are calculated from the data although the mean plane of each profile is different. Discussion is made on the calculation of two-dimensional surface profiles along the...
We report on simple high-sensitivity interferometric technique of detecting vibrations and present characteristics of laser vibrometer using GaAs and SnS 2 adaptive photodetectors based on the effect of the non-steady-state photoelectromotive force. It enables efficient direct conversion of high-frequency phase modulation of speckle-like optical wave reflected from the vibrating object into an output electrical signal with concomitant setting of optimal operation point of the interferometer and suppression of amplitude laser noise. The results of measurements of small vibration amplitudes of...