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The development is described of fiber Bragg grating (FBG) probes with single or four cores using spheres fixed onto optical fibers comprising Bragg gratings in their cores. Simulations and preliminary experiments were conducted to evaluate the performance of these FBG probes for dimensional metrology with micro parts of high aspect ratio. Simulation and experimental results indicate that a one-dimensional FBG probe with single core can be used to achieve an axial resolution of 100 nm at an aspect ratio of 15:1. A three-dimensional FBG probe with four cores can be used to achieve a theoretical axial resolution as high as that of a FBG probe with single core, with a capability of decoupling two-dimensional radial displacements with a resolution of 13 nm. [ABSTRACT FROM PUBLISHER]

Abstract: Nonrigid parts are traditionally mounted on over-constrained holding fixtures during inspection in order to support the part and maintain an acceptable level of measurements repeatability and reproducibility. The fixture's over-constrained configuration and restraining sequence are critical characteristics of the fixture and can become active components of the measurement system. Therefore, this paper investigates the profile measurements repeatability of an aluminum flat panel with respect to these aforementioned characteristics. To this end, this paper studies the measurements variability of the panel mounted on four over- constrained fixture configuration, each with two different restraining sequences. [Copyright &y& Elsevier]

Abstract: This paper presents a new virtual environment aimed to the realization of dimensional metrology practices, in the framework of the Degree in Mechanical Engineering of Technical University of Madrid. The development of this project allows the implementation of an interactive teaching model, focused on the student, which combines master classes and virtual applications, in an environment known as DE–learning (driven e-learning). This teaching tool directs and helps students on an individual way in the dynamic and interactive practice development. In particular, this module simulates the functioning, calibration and measurements using a horizontal coordinate measuring machine (HCMM). The program interface has been developed trying to create an easy-to-use environment for the students, in order to be a first contact with the HCMM and its possible metrological applications. [Copyright &y& Elsevier]

Abstract: This paper presents the problem of optical measuring machine calibration, emphasizing the calibration of the “optical system”, omitting the calibration of the “machine system”. The calibration of an optical measuring machine is the first step before using the instrument for any application. For this purpose, a mathematical model has been developed to transform the coordinates of a point in space (3D) into coordinates of a point in an image (2D). Using this camera model, a calibration procedure has been developed using a grid distortion pattern. Finally, a procedure for calculating the uncertainty of the camera and geometric distortion parameters based on the Monte Carlo method has been developed. [Copyright &y& Elsevier]

The purpose of this article is to show a software application made for online calibration via Internet from simple measuring instruments from the dimensional area (exterior micrometer and calliper). It also shows the educational results obtained in the teaching experiences where it has been used. The environment created makes it possible to replace real practices with virtual simulations where the student must make the proper metrological decisions and make the necessary calculations to determine the instruments' expanded uncertainty. This software has shown to be a very useful and efficient tool in training the distance learning students in the course titled: 'Calibration Plan for Ensuring Quality in Industrial Laboratories,' offered by Technical University of Madrid. Furthermore, some very notable academic results have been achieved among students from two pilot groups for the Mechanical Engineering degree program. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 387-399, 2013 [ABSTRACT FROM AUTHOR]

Quality control of micro components is an increasing challenge. Smaller mechanical parts are characterized by smaller tolerance to be verified. This paper focuses on the dimensional verification of micro injection-moulded components selected from an industrial application. These parts are measured using an optical coordinate measuring machine, which guarantees fast surface scans suitable for in-line quality control. The uncertainty assessment of the measurements is calculated and three analyses are carried out and discussed in order to investigate the influence parameters in optical coordinate metrology. The estimation of the total variability of the optical measurements and the instrument repeatability are reported; moreover, the measurement system capability is evaluated according to the measurement system capability indices Cg and Cg k. [ABSTRACT FROM AUTHOR]

Tilt and radial error motion of a laser tracker head as it spins about the two rotation axes result in small but measurable ranging and angle errors. The laser tracer, on the other hand, measures range with respect to the center of a high quality stationary sphere. It is therefore not expected to be influenced by the radial error motions of the carriage that carries the optics and the source, but the form error of the reference sphere and possibly the eccentricity in its placement with respect to the circular path traced by the carriage will be contributors to the ranging errors. In this paper, we describe experiments to assess the magnitude of these ranging errors as a function of the azimuth angle in different laser trackers and a laser tracer. [ABSTRACT FROM AUTHOR]

We describe the application of several surface profile filters as an enabling tool in the dimensional measurements of an engineering artifact, namely, a fuel cell plate. We recently reported work on the development of a non-contact system for dimensional metrology of bipolar fuel cell plates. That system comprises two laser spot triangulation probes that acquire profile data across a plate. While the non-contact system provides rapid measurements (measurement speed of 100 mm s-1 to 500 mm s-1), the data are noisy and cannot be used directly to obtain features of interest such as channel depth and width. In this paper, we show how different surface profile filters such as the spline, morphological, and robust filters, can be employed to identify and suppress outliers and to produce a mean line that serves as a substitute geometry from which we can determine features of interest. Further, we compare the non-contact probe data against contact probe measurements made using a coordinate measuring machine. Surface profile filters are again useful in correcting the reference data for tip size and also in removing any free form deformation in both data sets prior to parameter evaluation and comparison. [ABSTRACT FROM AUTHOR]

Abstract: With the development of micro systems in recent years, the demands for ultraprecision measurement become more important in the field of dimensional metrology. In this paper, a tactile probing system based on capacitive sensor for precision metrology is presented. The capacitive sensor is fabricated by MEMS technique, and a commercial micro-probe and the capacitive sensor are integrated together to constitute the initial probing system. The signal processing circuit is designed to be based on AD7747 chip which is substantially a high resolution, Σ-Δ capacitance-to-digital converter (CDC). Then the experiment set-up is configured and experimental results indicate that when a 0.3mm probing head is used, the probing system has a resolution of better than 10nm along axial direction and better than 25nm along radial direction. With the low residual nonlinear error, the proposed system can therefore be used for submicron measurement of small structures with dimension larger than 0.3mm and depth down to 2.3mm. [Copyright &y& Elsevier]

In a free state, nonrigid parts can take on different shapes compared to their design model. Such behavior of nonrigid parts introduces particular challenges to engineers during the geometric and dimensional requirements specification and inspection steps. Given that the choice of inspection method is guided by the requirement specification type, this paper presents two sections dealing, respectively, with the specification and the inspection method used for nonrigid parts. Accordingly, this paper proposes a categorization of the particular specification methods used for the geometric dimensioning and tolerancing of nonrigid parts under the American Society of Mechanical Engineers and International Organization for Standardization standards, as well as a review of the available approaches for the fixtureless inspection method of these parts. Typical applications of each specification method, as well as the advantages and drawbacks of their use, are proposed as general guidance. Finally, the current research trends into the fixtureless inspection methods of nonrigid parts are underscored. [ABSTRACT FROM AUTHOR]

A novel approach is proposed for the characterization of critical dimensions and geometric errors, suitable for application to micro-fabricated parts and devices characterized as step-like structured surfaces. The approach is based on acquiring areal maps with a high-precision optical three-dimensional profilometer and on processing topography data with novel techniques obtained by merging knowledge and algorithms from surface metrology, dimensional metrology and computer vision/image processing. Thin-foil laser targets for ion acceleration experiments are selected as the test subject. The main issues related to general applicability and metrological performance of the methodology are identified and discussed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In relation to the industrial need and to the progress of technology, Laboratoire National de M'etrologie et d'Essais (LNE) would like to improve the measurement of its primary pressure standards, spherical and flick standards. The spherical and flick standards are, respectively, used to calibrate the spindle motion error and the probe, which equip commercial conventional cylindricity-measuring machines. The primary pressure standards are obtained using pressure balances equipped with rotary pistons. To reach a relative uncertainty of 10-6 in the pressure measurement, it is necessary to know the diameters of both the piston and the cylinder with an uncertainty of 5 nm for a piston diameter of 10 mm. Conventional machines are not able to reach such an uncertainty level. That is why the development of a new machine is necessary. The purpose of this paper is to present the concepts and the architecture adopted in the development of the new equipment dedicated to cylindricity measurement at a nanometric level of a accuracy. The choice of these concepts is based on the analysis of the uncertainty sources encountered in conventional architectures. The architecture of the new ultra-high equipment as well as the associated calibration procedures will be described and detailed. [ABSTRACT FROM AUTHOR]

This paper is a study on the determination of the measurement uncertainty for a relatively simple and widespread calibration task. The measurement of a special form deviation of gauge blocks using the so-called five-point technique is discussed in detail. It is shown that the mainstream treatment of the measurement uncertainty (i.e. propagation of uncertainties) cannot be applied to this problem for principal reasons; the use of supplement 1 of the GUM (Monte Carlo method) is mandatory. The proposed model equation is probably the simplest 'real world' example where the use of supplement 1 of the GUM not only gives better results, but gives results at all. The model is simple enough to serve as a didactical example. Explicit analytical expressions for the probability density functions, expectation values, uncertainties and coverage intervals are given which is helpful for the validation of dedicated software products. Eventually a complete avoidance of the standardized form parameters in calibration certificates is proposed. The statement of 'corner-deviations' would be much more useful, especially for the evaluation of key comparisons. [ABSTRACT FROM AUTHOR]

Abstract: Combining multiple sensors on CMMs (Coordinate Measuring Machines) is useful to fulfil the increasing requirements on both complexity and accuracy in dimensional metrology. Yet, the methodology to plan measurement strategies for systems combining different types of sensors is still a major challenge. Such planning is commonly done in an interactive way. This paper presents a methodology which can create inspection plans automatically for CMM inspection combining a touch trigger probe and a laser scanner. The inspection features are specified based on the extracted geometry features and the associated PMI (Product and Manufacturing Information) items from a CAD model. A knowledge based sensor selection method is applied to choose the suited sensor for each inspection feature. For touch trigger measurements, the sampling strategy considers the measurement uncertainty calculated by simulation. A geometry-guide method is developed for collision-free probing path generation. For laser scan measurements, the required view angles and positions of the laser scanner are determined iteratively, based on which the scan path is generated automatically. The proposed methodology is tested for several cases and validated by measurement experiments. The methodology provides suited planning results and can be used for automated dimensional inspection, i.e. Computer Aided Quality Control (CAQC). [Copyright &y& Elsevier]

Abstract: Laser triangulation probes are increasingly used for dimensional measurements in a variety of applications. At the National Institute of Standards and Technology, we have recently explored the use of laser spot triangulation probes to determine dimensional features such as height and width of channels in a fuel cell plate. To assess the suitability of the probes for performing these dimensional measurements, we designed several experiments that highlighted different error sources in the probes. This report is a summary of those experiments. Numerous studies have been reported in the literature on error sources in laser triangulation probes utilizing artifacts of varying shape (form), color, reflectivity, surface finish, etc. However, our experiments are targeted towards establishing bounds on errors when measuring simple linear dimensions such as height and width on prismatic objects of a single color and material. Our scope is indeed narrow, but intentionally so; it is our objective to highlight the influence of a number of “hidden performance attributes” that impact accuracy of even simple linear dimensional measurements so that it may be of use to others who perform similar measurements. [Copyright &y& Elsevier]

Abstract: The purpose of this paper is to describe the objectives, methodology and structure of a virtual didactic environment developed by the educational research group New Teaching Methodologies in Mechanical Engineering and Manufacturing at the Technical University of Madrid, designed to carry out dimensional metrology practical lessons. This development has allowed teaching to be focused on the student in a DE-learning (driven electronic learning) environment capable of efficiently replacing the traditional method based on master classes and practical hands-on experience with real equipment. In fact, the developed environment directs and assists students, step by step, in their practical experience, proving dynamic and interactive through the use of animations, video and audio contributions, connections with hypertexts and simulations. The model presented in this work seeks a progressive adaptation to the new training paradigms, incorporating emerging communication technologies so that students can harness an even greater role that has hitherto been untapped, hence approaching one of the objectives in the Bologna process. The project has been undertaken entirely with the software house Macromedia: Director MX 2004 and Flash MX 2004, which has afforded the creation of a multimedia application with animations of the highest quality. Scripting languages (Lingo, JavaScript and ActionScript) have likewise been incorporated, permitting the evolution of even more complex elements for user interaction. The project has been undertaken in Spanish and English with a view to meeting the communication needs of students in a multicultural environment, in harmony with the framework program for didactic strategies in the European Higher Education Area. [Copyright &y& Elsevier]

Abstract: Dimensional metrology is an important part of any manufacturing system. It consists of distinct components and requires a large, diverse, and interconnected knowledge base. How to pass information seamlessly with minimal cost and minimal data loss between different components of a dimensional metrology system is a major issue that concerns software and hardware vendors, standards developers, and customers. This paper focuses on the four main elements of a dimensional metrology system: product definition, measurement process plan definition, measurement process execution, and analysis and reporting of quality data. The activities and software modules that are involved in these elements are discussed. Key issues that cause interoperability problems are identified. These issues are discussed as they relate to the current situation in dimensional metrology standards development. The STEP (ISO 10303) standards are the product of an international effort to achieve interoperability for manufacturing systems. Extending STEP is an appropriate way to solve the interoperability problem within dimensional metrology systems. Further development of STEP standards is proposed so that Geometric Dimensioning and Tolerancing (GD&T) information already available in STEP can be linked with manufacturing feature information, measurement technology, and measurement results. The proposed STEP data model is an attempt to provide a standard that will support automatic measurement process plan generation for in-process on-machine measurement. Some case studies are under way to test the model. [Copyright &y& Elsevier]

Abstract: This paper discusses the aspects that influence the interaction between a probe tip and a work piece during tactile probing in a coordinate measuring machine (CMM). Measurement instruments are sensitive to more than one physical quantity. When measuring the topography of a work piece, the measurement result will therefore always be influenced by the environment and (local) variations in the work piece itself. A mechanical probe will respond to both topography and changes in the mechanical properties of the surface, e.g. the Young''s modulus and hardness. An optical probe is influenced by the reflectivity and optical constants of the work piece, a scanning tunneling microscope (STM) responds to the electrical properties of the work piece and so on (Franks, 1991 ). The trend of component miniaturization results in a need for 3-dimensional characterization of micrometer sized features to nanometer accuracy. As the scale of the measurement decreases, the problems associated with the surfaceprobe interactions become increasingly apparent (Leach et al., 2001 ). The aspects of the interaction that are discussed include the deformation of probe tip and work piece during contact, surface forces during single point probing and scanning, dynamic excitation of the probe, synchronization errors, microfriction, tip rotations, finite stiffness effects, mechanical filtering, anisotropic stiffness, thermal effects and probe repeatability. These aspects are investigated using the Gannen XP 3D tactile probing system developed by Xpress Precision Engineering using modeling and experimental verification of the effects. The Gannen XP suspension consists of three slender rods with integrated piezo resistive strain gauges. The deformation of the slender rods is measured using the strain gauges and is a measure for the deflection of the probe tip. It is shown that the standard deviation in repeatability is 2nm in any direction and over the whole measurement range of the probe. Finally, this probe has an isotropic stiffness of 480N/m and a moving mass below 25mg. [Copyright &y& Elsevier]

In many branches of industry, dimensional measurements have become an important part of the production cycle, in order to check product compliance with specifications. This task is not trivial especially when dealing with large-scale dimensional measurements: the bigger the measurement dimensions are, the harder is to achieve high accuracies. Nowadays, the problem can be handled using many metrological systems, based on different technologies (e.g. optical, mechanical, electromagnetic). Each of these systems is more or less adequate, depending upon measuring conditions, user's experience and skill, or other factors such as time, cost, accuracy and portability. This article focuses on a new possible approach to large-scale dimensional metrology based on wireless sensor networks. Advantages and drawbacks of such approach are analysed and deeply discussed. Then, the article briefly presents a recent prototype system - the Mobile Spatial Coordinate-Measuring System (MScMS-II) - which has been developed at the Industrial Metrology and Quality Laboratory of DISPEA - Politecnico di Torino. The system seems to be suitable for performing dimensional measurements of large-size objects (sizes on the order of several meters). Owing to its distributed nature, the system - based on a wireless network of optical devices - is portable, fully scalable with respect to dimensions and shapes and easily adaptable to different working environments. Preliminary results of experimental tests, aimed at evaluating system performance as well as research perspectives for further improvements, are discussed. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an optimised method for the characterization of circular features of any amplitude, which includes the capture of geometric data, by means of the use of three-coordinate measuring machine or digital optical machines with a CCD camera, and its subsequent mathematical processing. The proposed model determines the radius and the circularity error, based on the minimum zone method, and to this end it uses linear programming techniques, the Simplex programming principles and the limaçon approximation. An experimental study on ring gauges and reference disks is provided, including a comparative analysis using the Chauvenet and Grubbs filtering procedures. Last of all, an uncertainty estimation method is proposed by means of the Monte Carlo simulation. The experimental analysis carried out on ring gauges and reference disks accredit that the algorithm developed, implemented in a Matlab® environment, gives reliable results for any circumference arc considered, regardless of its amplitude. [Copyright &y& Elsevier]

This paper aimed at identifying the error sources that occur in dimensional measurements performed using atomic force microscopy. In particular, a set of characterization techniques for errors quantification is presented. The discussion on error sources is organized in four main categories: scanning system, tip-surface interaction, environment, and data processing. The discussed errors include scaling effects, squareness errors, hysteresis, creep, tip convolution, and thermal drift. A mathematical model of the measurement system is eventually described, as a reference basis for errors characterization, with an applicative example on a reference silicon grating. [ABSTRACT FROM AUTHOR]

Abstract: Multisensor data fusion in dimensional metrology is used in order to get holistic, more accurate and reliable information about a workpiece based on several or multiple measurement values from one or more sensors. The theoretical background originates in classical mathematics and statistics, in methods of artificial intelligence (AI) and in the Bayesian fusion approach. Sensor technologies and sensor characteristics influence the data fusion process and determine the gain of information compared to the application of a single sensor. Homogeneous and inhomogeneous sensor configurations lead to complementary, competitive and cooperative information integration with specific advantages depending on the application. The scope includes image fusion, tactile and optical coordinate metrology, coherent and incoherent optical measuring techniques, computed tomography as well as scanning probe microscopes. [Copyright &y& Elsevier]

In many branches of industry, most of manufacturing efforts are directed toward producing objects of specific forms and dimensions. Dimensional measurement is an important part of the production cycle, to check products compliance with specifications. For this, many substantial improvements in the existing technologies have been made, and new measuring systems have been introduced. This paper briefly introduces a recent measuring system— mobile spatial coordinate measuring system (MScMS)—which is suitable for performing dimensional measurements of large-size objects (dimension on the order of tens of meters). MScMS, thanks to its distributed wireless sensor network nature, is portable and can be easily arranged around the measured object. Furthermore, it does not require complex setup operations before being ready to perform measurements. After describing how the system works, we will compare it with well-tested and widespread instruments such as traditional coordinate measuring machines (CMMs), showing analogies and differences. The comparison is structured on the basis of different criteria, which are analyzed in detail in the first part of the paper. Although being able to perform similar measurements, CMMs and MScMS are different in technological features. CMMs are able to achieve higher level of accuracy, while MScMS is more flexible, cheap, and can be important to simplify the current measuring practices within large-scale industrial metrology. It can be concluded that these systems can easily coexist, as each system is suitable for specific applications. [ABSTRACT FROM AUTHOR]

In this paper, a new method that applies a piezoelectric translator to test the dynamic accuracy of scanning probes for coordinate measuring machines (CMMs) is proposed. The principle of the method is presented, and this method is used for the evaluation of measurement uncertainty. The validity of the method is experimentally confirmed on a bridge Zeiss PRISMO CMM equipped with a VAST XT scanning probe. [ABSTRACT FROM AUTHOR]

Abstract: A process based on nanoimprint lithography is proposed to manufacture linear encoders with a pitch below 1μm. A phase scale and a read head were manufactured by pattern transfer on silicon and glass, respectively. The process developed points out that this technology may be suitable for mass produced encoders with a very high resolution and/or accuracy in the nanoscale range. [Copyright &y& Elsevier]

One of the basic principles of dimensional metrology is that a part dimension changes with temperature because of thermal expansion. Since 1931 industrial lengths have been defined as the size at 20 °C. This paper discusses the variety of standard temperatures that were in use before that date, the efforts of C.E. Johansson to meet these variations, and the effort by the National Bureau of Standards to bring the United States to the eventual world standard. [ABSTRACT FROM AUTHOR]

A key focus of the CIRP CAT 2020 is the role of standardization in GPS specification, and the constraints and opportunities provided by standards throughout the design lifecycle, including in the verification of products. This focus is supported by two Keynote presentations from the chairmen of the ASME and ISO committees that develop standards for the specifications of geometric tolerances. The CIRP CAT conferences provide an opportunity for researchers and practitioners to exchange new ideas and discuss the implications of new and evolving research in the areas of geometrical tolerancing, assembly analysis, modeling of manufacturing processes, and standardization. [ABSTRACT FROM AUTHOR]

Abstract: This article reviews some design considerations for the scaling down in size of instruments and machines with a primary aim to identify technologies that may provide more optimal performance solutions than those, often established, technologies used at macroscopic, or conventional, scales. Dimensional metrology within emerging applications will be considered for meso- through micro-down to nanometer level systems with particular emphasis on systems for which precision is directly related to function. In this paper, attention is limited to some of the more fundamental issues associated with scaling. For example, actuator work or power densities or the effect of noise on the sensor signals can be readily evaluated and provide some guidance in the selection for any given size of device. However, with reductions in scale these parameters and/or phenomena that limit performance may change. Within this review, the authors have tried to assess these complex inter-relationships between performance and scale, again from a fundamental perspective. In practice, it is likely that the nuances of implementation and integration of sensor, actuator and/or mechanism designs will determine functionality and commercial viability of any particular system development. [Copyright &y& Elsevier]

Abstract: A method based on Nanoimprint lithography is proposed to manufacture linear encoders in the microscale range. A phase scale and a read head were manufactured by pattern transfer on silicon and pyrex, respectively. The developed process points out that this technology may be suitable for mass produced encoders with very high resolution and/or accuracy in the microscale as well as in the nanoscale range. [Copyright &y& Elsevier]

The analysis of probe operational parameters such as configuration of the probe, including triggering (measuring) force, stiffness, and length of the stylus, has been performed. A new method allowing three-dimensional (3-D) probe error characteristics with several times more accuracy than the procedure used on a coordinate measuring machine (CMM) has been applied. The analyses have been performed for devices of two types: a single-stage and a two-stage switching probe. The influence of the above-mentioned parameters has been analyzed theoretically and verified experimentally in two planes: perpendicular and parallel to the probe axis. Good agreement between the proposed theoretical model and experimental data has been obtained. [ABSTRACT FROM AUTHOR]

Abstract: Influence of the measured objects parameters on coordinate measuring machine (CMM) touch trigger probe inaccuracy of probing is investigated. Factors such as material stiffness of measured workpiece, its surface shape and roughness are taken into consideration. The measuring method out off CMM, based on a rotary table and a reference axis is applied for tests. The concept is based on measurements of the distance between reference and triggering points in various directions. The reference points are established by the rotation of a precise rotary table. The statistical analysis of variance and regression is applied for data analysis. [Copyright &y& Elsevier]

Abstract: A new method of testing of touch trigger probes for coordinate measuring machines (CMM) has been proposed. The concept is based on measurements of the distance between reference and triggering points in various directions. The reference points are established by the rotation axis of a precise rotary table. The advantage of this method relies on easy realisation with application of a commercial device for roundness error measurement. The accuracy of the presented method is much higher in comparison with the existing procedures of CMM probes calibration. The mathematical principle of the method has been presented and used for evaluation of its uncertainty. The validity of the method was experimentally confirmed by means of one- and two-stage type probes. [Copyright &y& Elsevier]

Abstract: In Brazil dial gauges are among the mostly used measurement instruments in industrial dimensional metrology. The objective of this work is to study the positioning effect of the dial gauge in the vertical position and in the horizontal position on the uncertainty of their results in tests and measurements. By using a system with optical solution (laser), with an interferometer method of displacement control, calibrations were performed in six new dial gauges, from two different manufacturers, with scale interval of 0.01mm and measuring range of 10mm. All differences between the obtained values were below the values of the calculated uncertainties of the involved calibration processes. No meaningful differences are noticed, when the dial gauge is either in vertical or horizontal position. This factor produces an effect that does not deserve being considered as a source of meaningful contribution to the final uncertainty of the results of measurements. [Copyright &y& Elsevier]