Abstract Recent advances are described in the measurement and definition of surface microgeometry, with special emphasis on the role of the stylus instrument. Statistical descriptions of surfaces are discussed and it is shown that the geometry of surface profiles can be specified completely by two parameters, the r.m.s. roughness and the correlation length. Hardware and…
Abstract The structure function, which is related simply to the autocorrelation function but is without some of its disadvantages, is proposed as a means of quantifying variations in surface texture. Both profile and surface structure functions can be computed; the latter conveniently shows the effect of anisotropy on roughness. Using the structure function, the plastic…
Abstract This paper presents a novel approach for the mapping of geometric errors of machine tools and coordinate measuring machines by a single tracking interferometer. The concept is based on interferometric displacement measurements between reference points that are fixed to the base and offset points fixed to the machine head. The experimental comparison with an…
Abstract This paper describes a procedure used to determine the measurement uncertainties of spherical measurement systems. This procedure requires measuring a series of unknown yet fixed points from several different instrument locations. The resulting observations are then bundled to determine the set of instrument locations that minimizes the observational discrepancies of the system. We shall…
Abstract A spherical cat’s-eye retroreflector made from a glass material having a refractive index of two was developed. The geometrical sphericity of the cat’s eye and the sphericity examined optically were approximately 100 nm and 500 nm respectively. The discrepancy between these two values is discussed. This optical device is very versatile in terms of…
Abstract The field of Large-Scale Metrology has been studied extensively for many decades and represents the combination and competition of topics as diverse as geodesy and laboratory calibration. A primary reason that Large-Scale Metrology continues to represent the research frontier is that technological advances introduced and perfected at a conventional scale face additional challenges which…
Laser tracker/5 Abstract This paper describes two laser tracking techniques currently under development at the National Bureau of Standards for robot performance measurements. Tests indicate that the system can be used in real-time to determine the three-dimensional static and dynamic positioning accuracy of a robot end-effector to a few parts in 100,000 (i.e. 12.5–50 μm…
Laser Tracker/1 Abstract Thirty years since their invention, laser trackers are now recognized as the measurement tool of choice in the manufacture and assembly of large components. The general design of laser trackers, i.e., a ranging unit on a two-axis gimbal, has not changed significantly over the years. However, innovations in ranging technology, for example,…
X Ray CT/11 Abstract An increasing number of industrial sectors are considering the potential of additive manufacturing as an asset to improve theirproduction. Indeed, additive manufacturing enables the fabrication of very complex geometries and inner cavities that cannot bemanufactured with conventional techniques. However, in critical sectors such as aerospace, defence and medical, the parts needto…
X Ray CT/10 Abstract As the use of multi-material objects in industry continues to rise, the need for geometrical quality control by means of computed tomography-based coordinate measurement systems (CT-based CMSs) for entire geometries is rising as well. But the lack of international standards and the limited knowledge available on the influence of multi-materials on dimensional CT…
X Ray CT/9 Abstract This paper presents a set of modular test parts specially designed for the evaluation of the extraction operation using CT measuring systems. The motivation in developing the test parts was to individually quantify different types of CT-induced measurement errors and their influence on measurement results. The characteristics of the test parts…
X Ray CT/8 Abstract X-ray Computed Tomography (XCT) has become a common tool for dimensional analysis as it allows for non-destructive internal and external measurements. Manufacturers often specify the accuracy of dedicated metrology XCT systems as a maximum permissible error (MPE) statement determined using workpieces, test lengths and positions that are significantly different between manufacturers….
