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A major problem in finding the flow stress in metal cutting is the intense circumstances under which deformation takes place in the chip root. Large deformations are imposed on the workpiece material at high speed in a very small area. This results in mechanical material behaviour far removed from that encountered in conventional material tests. Therefore, to determine the flow stress in cutting it is necessary to determine the conditions under which the material is being deformed. This paper describes how the strains, strain rates and temperatures have been determined in orthogonal cutting tests of steel AISI 1045 and aluminium AA 6082-T6. It appears that in the region where the chip is separated from the workpiece (i.e. the primary shear zone) the workpiece material is sheared considerably to equivalent strains in the order of 1–2. Also, the strain rate in the primary shear zone is found to be very large: in the order of 2.0×104 s−1. To find the temperatures in metal cutting an IR camera is used. It appears that the feed rate and cutting speed hardly influence the shear plane temperature. The measured shear plane temperature is approximately 290 °C in the case of the steel and approximately 190 °C in the case of the aluminium alloy.

New measurement techniques and methods for characterizing the quality of optical fibers are presented. The fibers are to be used in a single-fiber-fed heterodyne laser interferometer with nanometer uncertainty. The polarization-mixing properties of several different polarization-maintaining fiber types, as well as the effects of fiber lengths on high-precision length measurements, is investigated for the first time. Mixing ratio and polarization orthogonality were measured using three different methods. The measured mixing ratios varied between 1:100 and 1:1650 (intensity). Also the influence of the fiber assembly on the polarization-mixing properties is shown.

ispartof: pages:264-265 ispartof: Proceedings of the 4th EUSPEN international conference pages:264-265 ispartof: 4th EUSPEN international conference location:Glasgow date:31 May - 2 Jun 2004 status: published

ispartof: pages:17-18 ispartof: Proceedings of the 4th EUSPEN international conference pages:17-18 ispartof: 4th EUSPEN international conference location:Glasgow date:31 May - 2 Jun 2004 status: published

In form and roughness measurements, often surfaces are measured which are approximately straight, round, or smooth. Measuring such surfaces often gives measurement results in which noise plays a role. This noise may give an offset in a measurement parameter as the noise makes the parameter, e.g. the flatness deviation of the Ra -value, deviate away from zero. In this paper we propose a method to correct for this noise bias for the roughness parameter Rq which is equivalent to the standard deviation. By considering the decrease in Rq once an average over multiple measurements is made, an unbiased value for Rq is estimated by extrapolating the value to an infinite amount of measurements. It is shown that using this method for two profile measurements only, the true measurand is approached better than with averaging dozens of measurements. This principle is extended to obtain a complete 'noise-corrected' profile by considering the power spectrum and the change of each Fourier component with averaging. As for each Fourier component few estimations are available, the method only has advantages when many measurements are taken. Combining the two methods and considering the statistical significance of each Fourier component enables a further reduction. Simulation and measurement examples are shown for roughness and roundness measurments. Keywords : noise reduction, uncertainty, roughness, form, roundness

ispartof: pages:307-310 ispartof: Proceedings of the ASPE 18th Annual Meeting pages:307-310 ispartof: ASPE 18th Annual Meeting location:Portland, Oregon, USA date:26 Oct - 31 Oct 2003 status: published

ispartof: pages:8-18 ispartof: Proceeding s of Micro system technologies 20013: international conference and exhibition on micro elecro, opto, mechanical systems and components pages:8-18 ispartof: Micro system technologies 20013: international conference and exhibition on micro elecro, opto, mechanical systems and components location:Munich date:7 Oct - 8 Oct 2003 status: published

In displacement interferometry, beam delivery by optical fibres is an important issue as this enables to keep the laser source, which acts as a heating source, away from the path in which a displacement needs to be measured. A complication is the polarisation state of the laser beam, which needs to remain undisturbed as much as possible. We use a set-up in which a single polarisation-preserving fibre is used for both polarization directions which are used in heterodyne interferometry. To correct for strain- and temperature effects, a reference phase measurement is made after the fibre. Various types of polarisation-preserving fibres have been measured with regard to their polarisation-preserving properties. It is shown that with a good quality optical fibre and with proper alignment and phase-compensation methods, the remaining periodic non-linearities in a displacement measurement can be within a few nm. ispartof: pages:479-482 ispartof: Proceedings of Euspen international topical conference on precision engineering, micro-technology, measurement techniques and equipment pages:479-482 ispartof: Euepen international topical conference on precision engineering, micro-technology, measurement techniques and equipment location:Aachen date:19 May - 20 May 2003 status: published

Since the wafer industry in using an increasing amount of double side polished wafers, the future of wafer metrology is very likely to shift from capacitance gauging techniques to optical measurement techniques. Participating in an international project the Technical University of Eindhoven is developing a self calibrating, traceable double side wafer flatness and thickness measurement device.By using proper measurement principles and advanced software a robust traceble wafer thickness measurement instrument is created which combines high lateral resolution, nanometer accuracy, high speed and low cost. The data analysis used in this scanning interferometer involves multiple phase extraction methods, newly developed robust unwrapping methods, surface stitching and smart measuring strategies for the application of software compensation techniques.

In dit artikel wordt een beknopt overzicht gegeven van wat er recentelijk is veranderd in de normgeving op het gebied van ruwheid. Met ruwheid wordt hierbij bedoeld het produceren, meten en verwerken van oppervlakteruwheid. Deze veranderingen worden uitgelegd aan de hand van de verschillende schakels in de normketen.

A popular approach to nano-positioning requirements in precision engineering in general and micro-lithography in particular is to subdivide the stage positioning architecture into a coarse positioning module with micrometer accuracy (Long Stroke), onto which a fine positioning module (Short Stroke) is cascaded. The latter is responsible for correcting the residual error of the coarse positioning module to the last nanometers. High accuracy positioning in 6 Degrees Of Freedom put severe constraints on the actuators and/or bearing systems. Actuators are used for generating a varying force being part of a control loop. Bearing systems should generate a force as constant as possible in the bearing direction, but the force perpendicular to that direction should be as low as possible. Actuators could serve as a bearing system, but on the one hand this would require the actuators to be large and thus heavy and on the other hand a substantial amount of heat is continuously dissipated in order to generate the static forces. Such heat generation does not contribute to the positioning performance of the actuators, but significantly affects the thermal stability of the application. The latter implication will be overcome if the bearing system is established by a system with permanent magnets.

In coordinate measurement metrology, assessment of the measurement uncertainty of a particular measurement is not a straight forward task. A feasible way for calculation of the measurement uncertainty seems to be the use of a Monte Carlo method. In recent years, a number of Monte Carlo methods have been developed for this purpose, we have developed a Monte Carlo method that can be used on CMM's that takes into account, among other factors, the auto correlation of the error signal. We have separated the errors in linearity errors, rotational errors, straightness errors and squareness errors. Special measurement tools have been developed and applied to measure the required parameters. The short-wave as well as the long-wave behavior of the errors of a specific machine have been calibrated. A machine model that takes these effects into account is presented here. The relevant errors of a Zeiss Prismo were measured, and these data were used to calculate the measurement uncertainty of a measurement of a ring gauge. These calculations were compared to real measurements.

This paper reports the fourth set of results of a series of grouped laser comparisons from national laboratories undertaken by the Bureau International des Poids et Mesures (BIPM) at the request of the Comite Consultatif pour la Definition du Metre (CCDM; now the Consultative Committee for Length, CCL) during the period July 1993 to September 1995. The results of this comparison, involving eleven lasers from eight countries and the BIPM, again meet the goals set by the CCDM in 1992 and adopted by the Comite International des Poids et Mesures (CIPM) the same year. The standard uncertainty of the frequency of the He-Ne laser stabilized on the saturated absorption of 127I2 at [lambda] approximately equals 633 nm is reduced to a level of 12 kHz (2.5 parts in 1011) when the lasers compared meet the recommended values of the parameters. The lasers were first compared with the BIPM4 laser with the parameters set to the values normally used in each laboratory; using the BIPM4 laser as a reference the results ranged from -15.4 kHz to 36.8 kHz. After checking and readjusting the values of all the parameters, the range was reduced to -8.6 kHz to 14.0 kHz. Under the latter conditions, the average frequency difference of the group of lasers, with respect to the BIPM4 laser, was 2.7 kHz with a standard uncertainty (1 [sigma]) of 8.1 kHz. The best relative frequency stabilities, with Allan standard deviations of about 5.5 parts in 1012 and 4.6 parts in 1013, were observed with sampling times of 1 s and 100 s, respectively. [Author abstract; 16 Refs; In English]

An interferometer is realized, based on the Twyman-Green Interferometer principle for the calibration of long gauge blocks and length bars in the 100-1000 mm range with an uncertainty of 0.02 micrometers + 0,1 micrometers /m. Also the expansion coefficient of gauge blocks and even of rod-shaped materials with non-optical flat faces can be calibrated in the 18-22 degrees C range with an uncertainty below 1 X 10-7/K. The set-up basically follows the most commonly used interferometer arrangements for long gauge blocks as they are described by Darnedde, Ikonen and Lewis where the most similarities with the latter occur. The set- up has some peculiarities which make the measurement straightforward, accurate and reliable.

An instrument for the measurement of ball diameters in the 0.5-20 mm range in a gauge block interferometer is realized. The measurement principle is that the ball is positioned between an optical flat and a calibrated gauge block. The total length is measured in a gauge block relative to the optical flat and proper measurement of the deformations due to the measuring force. The parallelism is adjusted while viewing the interference patterns on the gauge block and the optical flat. The measuring force can be varied in the 0.03- 2.35 N range. The applied force is calibrated. Experiments show that commonly used formulas to calculate the ball indentation as a function of the applied force are approximately correct; this instrument however provides a direct means to measure this dependence and to apply a proper extrapolation to zero measuring force. The design is rather compact so it will fit in commonly used gauge block interferometers. The uncertainty which can be achieved is less than 0.1 micrometer.

This paper describes an iterative method which can be applied to geometrical problems in whicha large number of measurements are available out of which a large number of parameters are to becalculated. The method is based on the fact that a minimum sum of squared differences between anassumed value of a parameter and a number of independent measurements, is achieved when theparameter has the average value. This principle is applied to the problem of flatness measurementwith a gradient measuring device such as an electronic level (typically 180 measurements, 100parameters for a 10 x 10 grid) and to the measurement of a grid using distance measurements alongthe axes and along the diagonals(e.g. 342 measurements, 200 parameters for a 10 x 10 grid). The type A uncertainty of the result is estimated from simulated measurements in which simulated random measurements are superimposed on exact measurements derived from the known solution.This enables the derivation of uncertainties in coordinates relative to a defined orientation; e.g. theminimum zone plane in flatness measurements. It is shown that in both problems an uncertainty inthe results can be achieved which is about equal to the uncertainty of the single measurements.Methods are proposed to combine these uncertainties with type B uncertainties such as an uncertaintyin the temperature gradient in flatness measurements or the temperature uncertainty in grid measurements.

This paper describes a system which enables a traceable dynamic calibration of probes of e.g. roughness testers and roundness testers. The system is based on a Digital Piezo Translator (DPT). For the calibration of the DPT itself, an interferometric technique has been used. After calibration by laser interferometry, the DPT is used as a transfer standard which can be driven by signals of various, but exactly known, form. This time-displacement form can range from square to sinusoidal or quasi-random with a maximum displacement of 15 and a maximum frequency of about 300 Hz. From a practical calibration of a roughness tester it is shown that, depending on the profile, roughness parameters can be measured with an uncertainty ranging from a few nm to 1%.