Virtual Instruments in Dimensional Metrology

During the last five years, in order to improve understanding of content related to "Coordinate Metrology", the Laboratorio de Metrología y Metrotecnia (LMM) from the Polytechnic University of Madrid offers its PhD students, as a course work, the construction of a virtual instrument. This virtual instrument simulates the imaging of a part to be measured by optical dimensional metrology instruments (microscopes, profile projectors, vision machines). The LMM provides students with images similar to those they would obtain with real instrumentation for the instrument adjustment and calibration process. Working with these images, students should determine the adjustment parameters of the virtual instrument. Once these parameters are set, the student can perform the proper calibration of the virtual instrument. Beyond this process, the instrument is already able to perform traceable measurement. In order to do that, LMM offers students some images of parts. Students should perform some measurements using those images and estimate the corresponding uncertainties

Review of the mathematical foundations of data fusion techniques in surface metrology

The recent proliferation of engineered surfaces, including freeform and structured surfaces, is challenging current metrology techniques. Measurement using multiple sensors has been proposed to achieve enhanced benefits, mainly in terms of spatial frequency bandwidth, which a single sensor cannot provide. When using data from different sensors, a process of data fusion is required and there is much active research in this area. In this paper, current data fusion methods and applications are reviewed, with a focus on the mathematical foundations of the subject. Common research questions in the fusion of surface metrology data are raised and potential fusion algorithms are discussed

Fuzzy Logic Applications in Metrology Processes

Three-dimensional metrology is concerned with checking the conformity of machined parts with the geometrical specifications on their definition drawings from the design office. Three-dimensional measurement is a firmly established technique in the industry. For this, we apply the fuzzy logic to solve probing. Probing technology is widely used in three-dimensional metrology. In addition, we measure the very small dimensions, that is, the measurement at the micrometer scales. This chapter presents a new approach to the developing gear curve (CMMs). This method aims to select the most likely contact point for each successive arc by applying geometrical criteria and a fuzzy logic estimator, as you know there are several methods, but the fuzzy logic is more efficient and closer to the profile reel. The fuzzy logic system is particularly suitable for application to the three-dimensional metrology, including applications on a small radius probe as well as probing discontinuities to the flank profile. In addition, the time allowed is 144.09 s. Tests were carried out on gearboxes of agricultural machinery in the factory of my country (Algerian Tractors Company)

Dimensional metrology and positioning operations: basics for a spatial layout analysis of measurement systems

Dimensional metrology and positioning operations are used in many fields of particle accelerator projects. This lecture gives the basic tools to designers in the field of measure by analysing the spatial layout of measurement systems since it is central to dimensional metrology as well as positioning operations. In a second part, a case study dedicated to a synchrotron storage ring is proposed from the detection of the magnetic centre of quadrupoles to the orbit definition of the ring.Comment: 60 pages, presented at the CERN Accelerator School CAS 2009: Specialised Course on Magnets, Bruges, 16-25 June 200

Surface dimensional metrology by optical triangulation

Non-destructive dimensional inspection of surfaces is an issue of utmost importance in a large number of situation in R&D and in the industrial world. An increasing number of surfaces and surface types must be microtopographically characterized in non-invasive ways. Optical triangulation in different approaches allow the establishment of metrological systems that by its inherent relative simplicity versatility robustness and reliability can cope with most modern requirements of the non-invasive inspection of objects and surfaces both smooth or rough. In this communication we will present a brief review of the work done at the Microtopography Laboratory of the Physics Department of the University of Minho, Portugal, on the development of methods and systems of optical triangulation based microtopographic inspection of surfaces.info:eu-repo/semantics/publishedVersio

Inertia compensation while scanning screw threads on coordinate-measuring machines

Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up measuring process while still maintaining high accuracy. However, in some cases accuracy drasticaly depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of some dynamic effects while scanning screw threads on coordinate-measuring machines

A newly conceived cylinder measuring machine and methods that eliminate the spindle errors

Advanced manufacturing processes require improving dimensional metrology applications to reach a nanometric accuracy level. Such measurements may be carried out using conventional highly accurate roundness measuring machines. On these machines, the metrology loop goes through the probing and the mechanical guiding elements. Hence, external forces, strain and thermal expansion are transmitted to the metrological structure through the supporting structure, thereby reducing measurement quality. The obtained measurement also combines both the motion error of the guiding system and the form error of the artifact. Detailed uncertainty budgeting might be improved, using error separation methods (multi-step, reversal and multi-probe error separation methods, etc), enabling identification of the systematic (synchronous or repeatable) guiding system motion errors as well as form error of the artifact. Nevertheless, the performance of this kind of machine is limited by the repeatability level of the mechanical guiding elements, which usually exceeds 25 nm (in the case of an air bearing spindle and a linear bearing). In order to guarantee a 5 nm measurement uncertainty level, LNE is currently developing an original machine dedicated to form measurement on cylindrical and spherical artifacts with an ultra-high level of accuracy. The architecture of this machine is based on the ‘dissociated metrological technique’ principle and contains reference probes and cylinder. The form errors of both cylindrical artifact and reference cylinder are obtained after a mathematical combination between the information given by the probe sensing the artifact and the information given by the probe sensing the reference cylinder by applying the modified multi-step separation method.Thèse CIFR