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Dimensional measurements play a central role in enabling advanced manufacturing technologies, enhancing the quality of products and increasing productivity. This role becomes even more important in the context of Industry 4.0, where reliable and accurate digital models of products, processes and production systems are needed. To establish the traceability chain that links measurements in production to the length unit, dimensional artefacts – ranging from measurement standards to calibrated workpieces – are fundamental. The paper examines dimensional artefacts, discussing their characteristics, availability and role in supporting production by establishing metrological traceability, and provides guidelines for their selection, use and development.

Today, dimensional validation of polymer parts with micrometer level accuracy is performed long time after production because the part needs time to “settle” (which for some polymer materials takes weeks). However, manufacturing industry requires the measurements to be performed before part stabilization, to reduce the waiting time for quality control without compromising the level of accuracy. This work proposes an analytical solution for predicting the reference length of a classical 32 mm polymer part with an uncertainty of less than 10 μm when measured at non-reference conditions. Creep, moisture uptake and temperature are here the main issues to consider for polymer parts. The present study focuses on the dimensional changes governed by moisture uptake and creep with model parameters separately obtained by experimental studies combined with numerical simulations. Finally, the obtained analytical solution is used to predict the reference length of stabilized and non-stabilized polymer parts measured continuously over two months. The prediction shows good agreement with the reference values for settled parts at reference conditions.

In the present work a new method for thermal compensation in dimensional metrology of polymer parts in a production environment based on 3D thermomechanical simulations is developed. A fixture for measuring the length dimension of a classical polymer part is placed in a production environment and equipped with sensors in terms of thermocouples for temperature measurements of the part and the fixture and a contact probe for measuring the dimension. A 3D thermomechanical model is developed in ABAQUS, emulating the thermoelastic conditions of the polymer part when placed in the fixture. Knowledge from classical heat transfer and elasticity theory is then applied to derive a more generic, yet simple expression for the compensation from the transient 3D temperature and displacement fields, based on dimensionless values, which makes applicable for a wide range of initial and surrounding conditions found in a production environment. The developed expression is then used for length compensation on 24 samples measured inline ten minutes after production. The results reveals a significant improvement in capturing the transient behavior of the part with a reduced error from 13 μm to 3 μm, applying the developed formula instead of using more classical 1D standard thermal compensation.

A simple theoretical model linking surface micro geometry, friction and manufacturing cost is presented. Combining a basic geometrical relationship of plastic deformation of workpiece surface asperities by a hard tool with an assumption of adhesive friction, the friction coefficient of a soft, rough surface sliding against a hard, smooth tool surface can be calculated, linking surface roughness with friction coefficient. The simple model can also link the cost related to manufacturing with a surface characterized by a given friction coefficient value. Results are presented from tests carried out to verify the simple model. Several test pieces were manufactured by turning, or grooving, an aluminum alloy and brass using different feeds, tool nose radii, and tool nose angles, achieving different surface profiles. The surfaces were characterized using a stylus profilometer and a digital microscope. The static friction coefficient was determined in terms of angle of repose using a rotary table. The experimentally determined values of the friction coefficient were compared with those predicted from feed, tool radius, and asperity angle. The tests have shown a good reproducibility, and a clear determination of the friction coefficient was possible. However, due to the low normal loads involved in this set up, the influence from the surface roughness was not clear. Further investigations are therefore proposed.

In a comparison including 20 laboratories, a physical as well as a virtual assembly provided as two data sets were used to investigate measuring and post-processing approaches in computed tomography, CT. Different procedures were used in the comparison including one simulating in-line measurement. The comparison demonstrated that: (i) a tangible improvement in the use of CT compared to previous comparisons; (ii) most of the participants were able to reduce their scanning time by more than 70% without increasing the length measurement errors; and (iii) most of the participants can further reduce their uncertainties, thereby reducing the tolerance size that can be inspected using CT in industry.

This paper gives an update on current work concerning the development of the method of Dynamic Length Metrology (DLM) to obtain accurate traceable measurements directly in the production. Three case studies are described dealing with diameter measurements with sub-micrometer uncertainty on metallic parts, and dimensional measurements on polymer parts, where the achievable uncertainty of after molding predictions is of a few micrometers.

The growing demands for quality and flexibility and at the same time production speed challenges conventional metrology. The future tendency is that metrology is an integrated part of the production line and thus is placed in a production environment. This is a challenge since dimensional metrology in a production environment might lead to higher uncertainties due to dynamic variations both in the conditions of the environment and in the conditions of the produced parts. However, many of these effects can be treated as systematic errors if the physical phenomena leading to the deviations can be described. Today, it is very common to compensate for the variations in temperature in a classical 1D manner. However, when temperature gradients and very complex part geometries exist the deformation pattern might not at all follow a linear path. Instead, more advanced three-dimensional thermomechanical numerical models should be applied taking the inherent build-up of residual stresses and warpage into account.

In this work, the interaction between 3D optical scanners and objects realized with different materials and colours was investigated. The interaction is mainly related to the translucency of some materials, such as polymers, which is a category of materials in ever-increasing demand by industry. At the same time, the increase of the geometrical complexity of manufactured parts raises the need for the use of 3D optical scanners thanks to their rapidity and effectiveness. Translucency causes a subsurface scattering effect that has been modelled for certain cases and affects the dimensional accuracy of measurements, as well as the quality of reconstruction. Recently, an investigation considered its effect in dimensional verification using a structured light scanner with fringe projection. In this work, the investigation is extended to other 3D optical scanners exploiting different measuring principles: laser, structured light based on phase shifting and gray code, and photogrammetry. This was done in order to study how the subsurface scattering effect can vary with the materials, colours, and also the measuring principle used. To this end, five miniature step gauges made of different polymers and colours were used, and the effects due to their different optical properties investigated. The analysis focused on dimensional verification of bidirectional lengths, first calibrated with a traceable coordinate measuring machine. The quality of the reconstruction was also evaluated through the flatness values. According to the results obtained, translucency of materials has a dual and significant effect: a measurement bias and an increase of the uncertainty due to the different quality of reconstruction retrieved. Thus, it has to be considered properly for each case.

Full-scale deep drawing tests using tools featuring multifunctional surfaces are carried out in a production environment. Multifunctional tools display regularly spaced, transversal grooves for lubricant retention obtained by hard-turning, separated by smooth bearing plateaus realized by robot assisted polishing. Advanced methods are employed to characterise the tools’ surface topographies, detecting the surface features and analysing them separately according to their specific function. Four different multifunctional dies as well as two un-textured references are selected for testing. The tests are run using a non-hazardous, environmentally friendly lubricant, and the forming forces are constantly recorded. Multifunctional dies exhibit very good performances, with no galling occurrence and punch forces generally lower than the two references.

An investigation was carried out on the use of extrusion-cutting as a material test method operating at severe conditions of strain, strain-rate and temperature, such as in machining. In extrusion-cutting, a shoe constrains the chip back surface producing a geometrically defined orthogonal cutting process which can be modelled using methods from the theory of plasticity such as, e.g., slip-line and upper-bound. The process was previously proposed for use as a material testing technique to determine the shear flow stress of materials under strains, strain rates and temperatures relevant for analytical modelling of metal cutting. This work represents a new step where the final objective is the generation of stress-strain curves that can be used in analytical models as well as using Finite Element Method (FEM) simulations. A new experimental setup for extrusion-cutting using discs as workpieces was developed and implemented on a CNC lathe. An investigation was carried out extrusion-cutting copper discs using high-speed-steel cutting tools at 100 m/min cutting speed. Flow stress values for copper under machining-relevant conditions were obtained from measurement of the extrusion-cutting force on the tool and application of a simple upper-bound model for the extrusion-cutting process. An attempt to extend the validity of test data to cover a range of cutting conditions was made, and suggestions for improvement of the simple theoretical model given.

In this paper, a study is presented in which statistical methodologies were applied to evaluate the measurement of step gauges on an X-ray computed tomography (CT) system. In particular, the effects of step gauge material density and orientation were investigated. The step gauges consist of uni- and bidirectional lengths. By confirming the repeatability of measurements made on the test system, the number of required scans in the design of experiment (DOE) was reduced. The statistical model was checked using model adequacy principles; model adequacy checking is an important step in validating the applicability of a model to fitting experimental results. If the residuals after fitting the model are normally distributed (normality test), then the residuals represent random errors in the data. If the normality test is not satisfied, the model is said to fit the data poorly. If the model fit to the data were correct, the residuals would approximate the random errors (also called normality). The most common significance level is α = 0.05; for normality to be satisfied, the P value for the residuals must not be smaller than 0.05. The initial results show that the residuals failed the normality test due to a small P value ( P P value include (1) fitting a different model, (2) evaluating the data differently and (3) excluding outliers. The authors determined that there were too few data to delete outliers. Instead, discussions and conclusions were carried out based on main effect and interaction plots. It means that the conclusions were not based on the analysis of variance (ANOVA). The following conclusions can be drawn: X-ray scattering is more problematic for dense metal parts. Thus, the statement of “influence of orientation” should be constrained by the material type. But it is important to have in mention that probably the repeatability of the vertical case is much worse. This can be documented experimentally, by tracing back to the fitting quality of the planes. The fitting point deviation of these planes are typically larger when dense metal step gauges are scanned vertically; this can also be done with simulation, as it is “assumed” that the large errors related to “vertical direction” might be caused by X-ray scattering noise, this theory can be tested by simulating CT scans of metal and plastic step gauge without X-ray scattering and see whether “vertical direction” is still worse for aluminium step gauge.

In this paper, Bending-Under-Tension, an off-line test method simulating deep-drawing, is chosen for investigating the effectiveness of multifunctional (MUFU) surfaces in metal forming operations. Four different MUFU surfaces, characterized by a plateau bearing area and grooves for lubricant retention, are manufactured, together with two polished references. During the tests, surface texture is the only variable. The results show how MUFU surfaces perform better than the polished references, which produce severe galling, while MUFU surfaces with low bearing area display no clear evidence of galling. Metal-to-metal contact occurs anyway, but the strip material is pulverized and deposited onto the tool instead of cold-welding to it. The pockets create a discontinuity on the texture hindering pick-up propagation.

This article concerns the metrological characterization of the surface on a holding brake friction material pin after a pin-on-plate (POP) wear test. The POP test induces the formation of surface plateaus that affect brake performances such as wear, friction, noise and heat. Three different materials’ surfaces have been characterized after wear from data obtained with a focus variation 3D microscope. A new surface characterization approach with plateau identification is proposed, using the number of plateau on the surface, equivalent diameter, length and breadth as measurands. The identification method is based on determining and imposing ISO 27158-2 lower plateau limit (LPL) in material probability curves; and on applying a combined criterion of height segmentation threshold and equivalent diameter threshold. The method determines the criterion thresholds for each material since LPL appears typical by material. The proposed method has allowed quantifying the surface topography at two different levels of wear. An expanded measurement uncertainty of 3.5 µm for plateau dimensions in the range 50–2000 µm and one of 0.15 µm for plateau heights up to 10 µm have been documented.

This paper refers to testing of friction materials for holding brakes. In contrast to the more typical case of high energy brakes, holding brakes operate usually in a reciprocating sense, at very low sliding speeds and allow significantly higher clamping pressures. The design of a reciprocating pin-on-plate test-rig for studying the evolution of wear by monitoring the pin height reduction using Eddy-current proximity sensors is presented. Moreover, a new mechanism for recording the friction force is suggested. Apart from the design of the test-rig, friction force and wear rate measurements for two different friction materials running against an unhardened steel surface are presented as a usage case. © 2014 Elsevier B.V.

In a comparison involving 27 laboratories from 8 countries, measurements on two common industrial items, a polymer part and a metal part, were carried out using X-ray Computed Tomography. All items were measured using coordinate measuring machines before and after circulation, with reference measurement uncertainties in the range 1.5–5.5 μm, showing a good stability over the 6 months of the circulation. The comparison has shown that CT measurements on the industrial parts used lie in the range 6–53 μm, with maximum values up to 158 μm.

This paper presents the application of the substitution method for the estimation of measurement uncertainties using calibrated workpieces in X-ray computed tomography (CT) metrology. We have shown that this, well accepted method for uncertainty estimation using tactile coordinate measuring machines, can be applied to dimensional CT measurements. The method is based on repeated measurements carried out on a calibrated master piece. The master piece is a component of a dose engine from an insulin pen. Measurement uncertainties estimated from the repeated measurements of the master piece were transferred on to additionally scanned uncalibrated workpieces which provided the necessary link for achieving traceable measurements.

The paper concerns measurement of pin height for the determination of wear in a pin-on-plate (POP) or pin-on-disc (POD) test, where a pin is mounted on a holder that can be fixed on the test rig and removed for measurements. The amount of wear is assessed as difference of pin height before and after the test, using the distance between holder plane and pin friction plane as measurand. A series of measurements were performed in connection with POP testing of different friction material pins mounted on an aluminium holder. Pin height measurements were carried out on a coordinate measuring machine (CMM), achieving an expanded measurement uncertainty (k = 2) better than 1 μm. A simple dedicated fixture adaptable to workshop environment was developed and its metrological capability investigated, estimating an average uncertainty of measurement in the order of 5 μm (k = 2). Fixture measurements were compared with CMM measurements using the normalised En value. Acceptable En values (En < 1) were obtained in 58% of the measurements, showing a discrepancy which was explained in terms of different probing patterns on CMM and fixture.

One of the factors contributing to limited reproducibility of coordinate measurements is the use of different inspection software. Time-consuming efforts for translation of part programmes are sometimes needed, and interoperability of inspection equipment has the potential to reduce these inefficiencies. The paper presents a methodology for an economic evaluation of interoperability benefits with respect to the verification of geometrical product specifications. It requires input data from testing and inspection activities, as well as information on training of personnel and licensing of software. The model is illustrated using an automotive case study and the related assessment of an investment in interoperability.

Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possiblesolution is found in texturing the surfaces under tribological contact, as demonstrated by the development and spread of plateau-honed surface for cylinder liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper, a new test rig simulating pure sliding conditions is presented, dubbed axial sliding test. It presents four major components: a rod, a sleeve, a housing and a stripwound container. The rod and the sleeve are the two surfaces in relative sliding motion; the stripwound container maintains a constant, but adjustable normal pressure, and the housing serves as interface between the sleeve and the container. For carrying out the test, two machineries are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the containeradvancement is found. Preliminary tests are carried out involving a multifunctional and a fine-turned rod against a mirror-polished sleeve. Qualitatively, the multifunctional surfaces improve the friction conditions, but a more structured test campaign is required. It is furthermore assessed the repeatability of the test device, in order to rely on the results obtained. Ten repetitions made at the same pressure using the fine-turned rod displayed good repeatability of the force results both in terms of average values and trends.

A reaming operation had to be performed within given technological and economical constraints. Process improvement under realistic conditions was the goal of a statistical engineering project, supported by a comprehensive experimental investigation providing detailed information on single and combined effects of several parameters on key responses. Results supported selection of production parameters meeting specified quality and cost targets, as well as substantial improvements.

Computed tomography has entered the industrial world in 1980’s as a technique for non-destructive testing and has nowadays become a revolutionary tool for dimensional metrology, suitable for actual/nominal comparison and verification of geometrical and dimensional tolerances. This paper evaluates measurement results using different measuring strategies applied in different inspection software packages for volume and surface data analysis. The strategy influence is determined by calculating the measurement uncertainty. This investigation includes measurements of two industrial items, an aluminium pipe connector and a plastic toggle, a hearing aid component. These are measured using a commercial CT scanner. Traceability is transferred using tactile and optical coordinate measuring machines, which are used to produce reference measurements. Results show that measurements of diameter for both parts resulted in smaller systematic errors compared to distance and height measurements. It was found that uncertainties of all measurands evaluated on surface data were generally greater compared to measurements performed on volume data.

The paper gives a survey of the upcoming use of X-ray computed tomography (CT) for dimensional quality control purposes: i.e. for traceable measurement of dimensions of technical (mechanical) components and for tolerance verification of such components. It describes the basic principles of CT metrology, putting emphasis on issues as accuracy, traceability to the unit of length (the meter) and measurement uncertainty. It provides a state of the art (anno 2011) and application examples, showing the aptitude of CT metrology to: (i) check internal dimensions that cannot be measured using traditional coordinate measuring machines and (ii) combine dimensional quality control with material quality control in one single quality inspection run.

A novel artefact for calibration of the height in 3D microscopy is presented. The artefact comprises three steps having a common vertical axis, which allows z-coordinate calibration at different magnifications without requiring repositioning. The artefact is suitable for transferring traceability to 3D techniques at the micrometer and nanometer scale, e.g. 3D SEM, confocal microscopes etc. Two different series of samples were fabricated using EDM with three steps of 2–5–7 μm, and 20–50–70 μm, respectively, from a 3 mm diameter carbide wire. The artefact steps were calibrated on a stylus instrument according to ISO 5436 and measured on 3D microscopes.

The paper discusses effectiveness and resolution of five cutting tests (turning, milling, drilling, tapping, VIPER grinding) and their quality output measures used in a multi-task procedure for evaluating the performance of cutting fluids when machining aerospace materials. The evaluation takes into account the following process output measures: tool wear, cutting forces, torque, spindle power, geometrical accuracy, texture and integrity of workpiece surface. Using statistics, through calculation of the Hellinger distance, the resolution given by experimental data was evaluated and a comparison of robustness in ranking the performance of cutting fluids based on different output measures and cutting tests is presented.

The key comparison EURAMET.L-K8.2013 on roughness was carried out in the framework of a EURAMET project starting in 2013 and ending in 2015. It involved the participation of 17 National Metrology Institutes from Europe, Asia, South America and Africa representing four regional metrology organisations. Five surface texture standards of different type were circulated and on each of the standards several roughness parameters according to the standard ISO 4287 had to be determined. 32 out of 395 individual results were not consistent with the reference value. After some corrective actions the number of inconsistent results could be reduced to 20, which correspond to about 5% of the total and can statistically be expected. In addition to the material standards, two softgauges were circulated, which allow to test the software of the instruments used in the comparison. The comparison results help to support the calibraton and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In streamlined manufacturing systems, the added value of inspection activities is often questioned, and metrology in particular is sometimes considered only as an avoidable expense. Documented quantification of economic benefits of metrology is generally not available. This work presents concrete examples from industrial production, in which the added value of metrology in manufacturing is discussed and quantified. Case studies include: general manufacturing, forging, machining, and related metrology. The focus of the paper is on the improved effectiveness of metrology when used at product and process design stages, as well as on the improved accuracy and efficiency of manufacturing through better measuring equipment and process chains with integrated metrology for process control.

Measurement conditions and material properties have a significant impact on the dimensions of a part, especially for polymers parts. Temperature variation causes part deformations that increase the uncertainty of the measurement process. Current industrial tolerances of a few micrometres demand high accurate measurements in non-controlled ambient. Most of polymer parts are manufactured by injection moulding and their inspection is carried out after stabilization, around 200 hours. The overall goal of this work is to reach ±5μm in uncertainty measurements a polymer products which is a challenge in today‘s production and metrology environments. The residual deformations in polymer products at room temperature after injection molding are important when micrometer accuracy needs to be achieved. Numerical modelling can give a valuable insight to what is happening in the polymer during cooling down after injection molding. In order to obtain accurate simulations, accurate inputs to the model are crucial. In reality however, the material and physical properties will have some variations. Although these variations may be small, they can act as a source of uncertainty for the measurement. In this paper, we investigated how big the variation in material and physical properties are allowed in order to reach the 5 μm target on the uncertainty.

This paper presents development and application of a new software solution for stitching surface three-dimensional topography data where best matching positions are detected through maximization of a cross-correlation function. Differently from other stitching software tools developed in the past, the one here presented is based not on colour gradients but on matching of physical coordinates. The developed routine fully compensates positioning errors occurring when the measuring instrument is displaced relative to the surface. Qualitative as well as quantitative analyses were carried out in order to verify the applicability of the stitching process. Both synthetic and real scanned surfaces were used for testing. It was demonstrated that misalignments after software compensation are negligible: sub-pixel level inaccuracies, with absolute deviations

The paper presents implementation and validation of a method for accurate imaging of three-dimensional surface topographies, developed for AFM metrology but in principle applicable to the whole family of scanning probe microscopes. The method provides correction of the vertical drift, and can be applied to any AFM scanner system, without need for modification of the instrument hardware. Surface correction is performed based on two topographies taken with mutually orthogonal scanning directions. Reconstruction is rapidly achieved through the use of an automatic routine developed for the purpose. The proposed method has been tested by using an optical and a silicon flat and a high precision cylindrical artefact. Examples of successful reconstructions on different samples are also reported within the paper.

Experimental investigations were carried out in which the efficiency of cryogenic CO2 was compared to that of a commercial water based product with respect to tool life, cutting forces, chip disposal and workpiece surface finish. The experimental results show that CO2 applied at a rate of about 6 g/s is an efficient coolant for threading as well as for parting/grooving stainless steel. Threading can be carried out with gas alone but the best performance was obtained adding 6 ml/min unadditivated vegetable oil to the gas. In the case of parting/grooving, addition of oil (10 ml/min) to the gas is mandatory.

This paper presents the results of an extensive experimental investigation concerning size effects on surface generation by ball nose and flat end micro milling hardened tool steel. Cutting parameters were selected on the basis of a modular description of the uncut chip geometry. A theoretical model of the generated surfaces was used as a reference and compared with measurement results and visual inspection using an SEM. Two main effects have been observed on the tool-work material interaction at micro scale. These are responsible for the limited reduction of the roughness amplitude parameters with tool diameter and occur when the cutting edge radius to uncut chip thickness ratio becomes critical.

The need for dimensional micro and nano metrology is evident, and as critical dimensions are scaled down and geometrical complexity of objects is increased, the available technologies appear not sufficient. Major research and development efforts have to be undertaken in order to answer these challenges. The developments have to include new measuring principles and instrumentation, tolerancing rules and procedures as well as traceability and calibration. The current paper describes issues and challenges in dimensional micro and nano metrology by reviewing typical measurement tasks and available instrumentation. Traceability and calibration issues are discussed subsequently. Finally needs and gaps are identified based on these observations.

The implementation of replication techniques for mass production of microcomponents relies on the availability of tooling technologies for manufacturing of tools and moulds. Micromilling is a suitable technique for manufacturing of microstructures characterized by high aspect ratios and complex geometries as those characterizing injection moulding moulds. The realization of the micromilling process in connection with hardened tool steel as workpiece material is particularly challenging. The low strength of the miniaturized end mills implies reduction and accurate control of the chip load, which requires high positioning accuracy. Size effects, mainly related to the microstructure of the workpiece material and to the limited scalability of tool geometry and surface topography, critically influence the performance of the process in terms of part accuracy, surface roughness, cutting forces and tool wear. This paper presents the micromilling process applied to the manufacturing of microinjection moulding moulds in hardened tool steel, presenting experimental evidence and possible solutions to the above-mentioned issues.

This paper describes modelling of an integrated AFM - CMM instrument, its calibration, and estimation of measurement uncertainty. Positioning errors were seen to limit the instrument performance. Software for offline stitching of single AFM scans was developed and verified, which allows compensation of such errors. A geometrical model of the instrument was produced, describing the interaction between AFM and CMM systematic errors. The model parameters were quantified through calibration, and the model used for establishing an optimised measurement procedure for surface mapping. A maximum uncertainty of 0.8% was achieved for the case of surface mapping of 1.2×1.2 mm2 consisting of 49 single AFM scanned areas.

An interlaboratory comparison on mechanical and optical coordinate measuring machines (CMMs) was carried out in the period from August 2002 to November 2004. 15 different research laboratories were involved from 9 countries, with a total of 23 CMMs (12 mechanical and 11 optical) being used to measure an optomechanical hole plate, designed and manufactured by DTU, whereby it is possible to compare the performance of measurements obtained optically and mechanically. The comparison has shown that the optomechanical hole plate can be calibrated, following a well-established procedure for ball plate calibration, with uncertainties between 0.5 urn and 2 urn. Based on results from the comparison, optical CMM measurements can be divided in two groups. A group leading to deviations larger than 2 urn, and a group with deviations that are comparable to those obtained with mechanical machines. This comparison shows that optical coordinate measuring machines, generally speaking, can be as good as mechanical ones.

The efficiency of six cutting oils was evaluated in drilling AISI 316L austenitic stainless steel using conventional HSS-Co tools by measurements of tool life, tool wear, cutting forces and chip formation. Seven tools were tested with each fluid to catastrophic failure. Cutting forces and chip breaking were recorded for each bore, and tool wear was measured at constant intervals. A commercial mineral-based oil was taken as reference product, and five vegetable-based cutting fluids at different levels of additivation were tested. All measured parameters were in agreement, confirming that a performing fluid produces longer tool life, better chip breaking, lower wear and cutting forces. In particular, good correlation was found between tool life and cutting forces. Differences in cutting forces due to the fluid could be measured with a higher repeatability than tool life, thus resulting in a measurement capability comparable to that obtained using tool life as a performance criterion. As a consequence, it is suggested that drilling thrust can be used to assess the performance of cutting fluids in drilling stainless steel, resulting in considerable time savings and cost reduction with respect to tool life testing. All vegetable-based fluids performed better than the reference product. The best performance was obtained with a cutting fluid yielding 177% increases in tool life and 7% reduction in thrust force.

This paper addresses the role of surfaces at the micrometric and nanometric length scales. Applications, functional behaviour, and manufacturing issues are reviewed with respect to state-of-the-art and emerging products fabricated using high precision technologies. Examples of surfaces obtained with precision engineering, microengineering and nanotechnology are presented, encompassing surfaces in computers, MEMS, biomedical systems, light and X-ray optics, as well as in chemical systems. Surface properties at micro and nanoscale are considered, including geometry as well as physical and chemical properties. Different manufacturing processes are reviewed with respect to surface fabrication, encompassing conventional machining, microfabrication, and nanomanipulation. Surface metrology at micro and nanoscale is briefly addressed, and its fundamental importance strongly emphasized.

The scope of this work is to present a reverse engineering (RE) methodology for freeform surfaces, based on a case study of a turbine blade made of Inconel, including the reconstruction of its internal cooling system. The methodology uses an optical scanner and X-ray computed tomography (CT) equipment. Traceability of the measurements was obtained through the use of a Modular Freeform Gage (MFG). An uncertainty budget is presented for both measuring technologies and results show that the RE methodology presented is promising when comparing uncertainty values against common industrial tolerances.

X-ray Computed Tomography (CT) has become an important technology for quality control of industrial components. As with other technologies, e.g., tactile coordinate measurements or optical measurements, CT is influenced by numerous quantities which may have negative impact on the accuracy and repeatability of dimensional and geometrical measurements. The aim of this paper is to discuss different methods for the correction of scaling errors and to quantify their influence on dimensional measurements. Scaling errors occur first and foremost in CT systems with no built-in compensation of positioning errors of the manipulator system (magnification axis). This article also introduces a new compensation method for scaling errors using a database of reference scaling factors and discusses its advantages and disadvantages. In total, three methods for the correction of scaling errors – using the CT ball plate, using calibrated features measured by CMM and using a database of reference values – are presented and applied within a case study. The investigation was performed on a dose engine component of an insulin pen, for which several dimensional measurands were defined. The component has a complex geometry and is made of brass, which makes its measurements with CT challenging. It is shown that each scaling error correction method results in different deviations between CT measurements and reference measurements from a CMM. Measurement uncertainties were estimated for each method, taking into consideration the contributions related to the applied correction method. The newly suggested approach using the database appeared to work well, indicating, that if the properties of a CT system under investigation are monitored using a reference object (ball bar in our case), a correction factor based on individual selected magnification factors can be applied for scaling error correction of any object, and thus no additional scanning of a reference object is needed.

This paper presents an investigation on the effect of new formulations of vegetable oils on surface integrity and part accuracy in reaming and tapping operations with AISI 316L stainless steel. Surface integrity was assessed with measurements of roughness, microhardness, and using metallographic techniques, while part accuracy was measured on a coordinate measuring machine. A widely diffused commercial mineral oil was used as reference for all measurements. Cutting fluid was found to have a significant effect on surface integrity and thickness of the strain hardened layer in the sub-surface, as well as part accuracy. Cutting fluids based on vegetable oils showed comparable or better performance than mineral oils.

The paper describes the calibration and application of an integrated system for topographic characterisation of fine surfaces on large workpieces. The system, consisting of an atomic force microscope mounted on a coordinate measuring machine, was especially designed for surface mapping, i.e., measurement and tiling of adjacent areas. A calibration procedure was proposed involving a glass artefact featuring chromium lines with different pitch distances, giving the possibility to identify the exact position of single surface areas. The calibrated system was used to surface map a hip joint prosthesis consisting of a steel sphere with a polished surface having 3 nm roughness.

Recent advancements and some emerging trends in the methods and instruments used for surface and near surface characterisation are presented, considering the measurement of both topography and physical properties. In particular, surfaces that present difficulties in measurement or require new procedures are considered, with emphasis on measurements approaching the nanometre scale. Examples of new instruments and promising innovations for roughness measurement and surface integrity characterisation are presented. The new needs for tolerancing, traceability and calibration are also addressed.

A procedure is proposed for the evaluation of those uncertainty components of a single cutting force measurement in turning that are related to the contributions of the dynamometer calibration and the cutting process itself. Based on an empirical model including errors from both sources, the uncertainty for a single measurement of cutting force is presented, and expressions for the expected uncertainty vs. cutting parameters are proposed. This approach gives the possibility of evaluating cutting force uncertainty components in turning, for a defined range of cutting parameters, based on few experiments.

Sensor monitoring of chip form during longitudinal turning of carbon steel Ck45 was carried out through the detection and analysis of cutting force sensor signals. Both single chip form classification and favourable/unfavourable chip form identification were considered. Signal processing for feature extraction was carried out through a parametric method of spectral estimation. Decision making on chip form typology was performed through a supervised neural network (NN) approach, using diverse back-propagation feed-forward NN configurations, in view of the development of an on-line and real time chip form control procedure.

One of the major problems in forming of stainless steel sheet is galling due to lubricant film breakdown leading to scoring and bad surface quality. In a Danish research programme new lubricants substituting the normally applied chlorinated paraffin oils are being developed and tested for this purpose. In order to determine the limits of lubrication of these new lubricants, as well as commercial ones already available on the market, two sheet forming tests have been developed. Quantification of the degree of galling is done by roughness measurements on the workpiece surface. In a strip reduction test, this is done by 2D profilometry at strip locations corresponding to different sliding lengths, whereas a deep drawing test is based on 3D roughness mapping of local areas.

The reproducibility of a reaming test was analysed to document its applicability as a performance test for cutting fluids. Reaming tests were carried out on a drilling machine using HSS reamers. Workpiece material was an austenitic stainless steel, machined using 4.75 m∙min-1 cutting speed and 0.3 mm∙rev-1 feed. A mineral straight oil and a water-based lubricant at two different oil concentrations were compared with respect to hole quality, evaluated in terms of surface finish (conventional average roughness parameter Ra and roughness profiles), and hole geometry (hole diameter and roundness). Process reproducibility was assessed as the ability of different operators to ensure a consistent rating of individual lubricants. Absolute average values as well as experimental standard deviations of the evaluation parameters were calculated, and uncertainty budgeting was performed. Results document a built-up edge occurrence hindering a robust evaluation of cutting fluid performance, if the data evaluation is based on surface finish only. Measurements of hole geometry provide documentation to recognize systematic error distorting the performance test.

The number of industrial applications of Computed Tomography (CT) is large and rapidly increasing. After a brief market overview, the paper gives a survey of state of the art and upcoming CT technologies, covering types of CT systems, scanning capabilities, and technological advances. The paper contains a survey of application examples from the manufacturing industry as well as from other industries, e.g., electrical and electronic devices, inhomogeneous materials, and from the food industry. Challenges as well as major national and international coordinated activities in the field of industrial CT are also presented.

The subject of this paper is an analysis of progressive, wear and other surface alteration processes which take place on deep drawing dies. The deep drawing process was simulated using strip test evaluation equipment. A theory on the influence of different surface alterations on the die surface topography was then, developed. The wear progress was quantified using conventional surface roughness parameters as well as a set of recently developed parameters based on the bearing curve and extended to thee dimensions. It was concluded from conventional surface roughness measurements that maximum wear takes place at angles of 20° and 70° from the vertical direction on the die. Furthermore, it was observed from three-dimensional measurements that the progressive wear is initialed by ploughing after only a few drawings and this mechanism continues until the die is worn out. In the investigations described in this work, the wear progress was interpreted using the. three-dimensional parameters Spk and Svk in terms ...

The calibration of CMMs using calibrated ball plates or hole plates is a well established technique. In the case of CMMs equipped with optical sensors based upon CCD cameras a series of artefacts based upon chromium-on-glass structures have been proposed. Calibration of these artefacts can not be performed using the reversal method which can be used for ball or hole plates. A new two-dimensional artefact based upon mechanical elements has been developed allowing both optical and mechanical probing and calibration. This artefact combines in one piece the possibilities of performance verification of both optical and mechanical CMMs. The mechanical elements have been manufactured with form errors less than 3 urn and using a special surface preparation that makes optical CNC-measurements non-problematic. Reproducibilities better than 0.5 μm have been obtained in optical probing. Calibration of the artefact can be carried out using reversal methods using both optical and mechanical probing.

This paper is concerned with the wear of PTFE seals used in connection with reciprocating ceramic-coated rods. An analysis of the relationship between the surface topography of ceramics and wear of PTFE seals was undertaken, formulating three hypotheses which have been investigated experimentally using a seal test rig and a system for three-dimensional surface roughness analysis. It was observed that no running-in of the rod surface lakes place and, consequently, the tribological situation never stabilizes. It was shown that seal wear rate is dependent on the number of asperities penetrating the lubricant film thickness, the wear rate being correlated to a functional parameter (Spk_0) which was especially developed to describe the peak height above the mean plane. Furthermore, it was illustrated how the structure of ceramics allows the lubricant to flow unhindered between isolated asperities in contrast to the traditionally polished structure of steel which restricts the lubricant flow. Presented at the 5...