For some companies, visual inspection has become an essential step when seeking to improve the quality of their products. The aim of this control is to be sure of the perceived quality of the product, which often goes well beyond the quality expected by the customer. For this type of control, the controller should be able to detect any anomaly on a product, characterize this anomaly, and then evaluate it in order to decide if the product should be accepted or rejected. This paper describes how this characterization can be carried out and, more specifically, how to measure the impact of the local environment of an anomaly on the perceived quality of the product.

A key ingredient to underpin process improvement is a robust, reliable, repeatablemeasurement system. Process improvement activity needs to be supported by accurate andprecise data because effective decision making, within process improvement activity,demands the use of “hard” data. One of the oldest and most established process improvementmethods is Deming’s Plan-Do-Check-Act (PDCA) cycle which is reliant on the check phase, ameasurement activity where data is being gathered and evaluated. Recent expansions of thePDCA such as the Six-Sigma Define-Measure-Analyse-Improve-Control (DMAIC) methodologyplace significant importance upon measurement. The DMAIC cycle incorporates the regimentedrequirement for the inclusion of measurement system analysis (MSA) into the breakthroughstrategy. The call for MSA within the DMAIC cycle is to provide the improvement activitywith a robust measurement system that will ensure a pertinent level of data during anyvalidation process. The Lean methodology is heavily centred on the removal of the sevenMudas (wastes) from a manufacturing process: defects, overproduction, transportation,waiting, inventory, motion and processing. The application of lean, particularly withinthe manufacturing industry, has led to a perception that measurement is a waste within amanufacturing process because measurement processes identify defective products. Themetrologists’ pursuit for measurement excellence could be construed as a hindrance by the“cost down” demands being perpetrated from the same organisation’s lean policy. So whatpossible benefits does enforcing the regimes of the lean and quality philosophies upon themeasurement process have and how does this ultimately enhance the process improvementactivity? The key fundamental to embed with any process improvement is the removal ofwaste. The process improvement techniques embedded within lean and quality concepts areextremely powerful practices in the drive to eradicate waste but there are numerouscontextual problems with the application of the process improvement activity and itsassociated measurement system. The application demands of the organisation may bedependent on a number of financial and resource constraints which may introduce reasonsnot to apply stringent measurement methodology and practice. The failure of variousprocess improvement activities due to poorly managed measurement activity has arguablynever been comprehensively analysed. Process improvement activity theory fully embellishesthe need for applied robust measurement systems, so how can process improvement andmeasurement be systematically aligned to gain benefits? The aim of this paper is toconsider whether lean philosophies can be integrated and applied within measurementsystems. The discussion seeks to identify if seven Muda exist within measurement systemsand whether in doing so this will lead to benefits for process improvement activities.

Evaluation of geometric deviations for the purpose of determining compliance with specified form tolerances requires the acquisition of numerous measured data points and extensive computation to accurately characterize the inspected part’s geometry. If there are not enough data points measured or when the measured points are not distributed properly on the measured surface a high level of uncertainty in characterizing the inspected part’s geometry can be expected. However, increasing the number of data point also significantly increases the computational time and also increases computational uncertainty by adding to instability of the optimization process required to find the minimum deviation zone. Selections of number and location of the measured date points need to be performed by understanding the significance of these two sources of uncertainties. This paper discussed the effect of sampling procedure on uncertainty and precision of flatness inspection.

In the manufacturing industry, many product characteristics are of one-sided tolerances. The process capability indices Cpu (u, v) and Cpl (u, v) can be used to measure process performance. Most research work related to capability indices assumes no gauge measurement errors. This assumption insufficiently reflects real situations even when advanced measuring instruments are used. In this paper we show that using a critical value without taking into account these errors, severely underestimates the α-risk which causes a less accurate testing capacity. In order to improve the results we suggest the use of an adjusted critical value, and we give a Maple program to get it. An example in a polymer granulates manufactory is presented to illustrate this approach.

Classic methodologies of DOE are widely applied in design, manufacture, qualitymanagement and related fields. The resulting data can be analysed with linear modelingmethods such as multiple regression which generates a set of equations, Y = F(X), thatenable us to understand how varying the mean of one or more inputs changes the mean of oneof more responses. To develop, scale-up and transfer robust processes to manufacturing wealso need to set the control tolerances of each critical X and understand the extentto which variation in the critical X’s propagate through to variation in theY’s and howthis may impact performance relative to requirements (or specifications). Visual toleranceanalysis provides a simple way to understand and reduce propagation of variation fromX’s toY’s usingmodels developed from DOE’s or historical data. This paper briefly introduces the conceptof tolerance analysis and extents this to visual tolerance analysis through defectprofiles and defect parametric profiles. With the help of visual tolerance analysis,engineering and statistical analysts can work together to find the key factors responsiblefor propagating undesired variation into responses and how to reduce these effects todeliver a robust and cost effective process. A case study approach is used to aidexplanation and understanding.

Manufactured parts are affected by size and form errors, which need to be assessedagainst geometrical and dimensional tolerances in order to meet the functionalrequirements they have been conceived for. The compliance assessment of workpieces withspecifications depends on measurements and is unavoidably affected by several uncertaintycontributions. According to the geometrical product specifications and verification (GPS),measurement uncertainty consists of method and implementation uncertainty. Literatureproposes different approaches for the evaluation of implementation uncertainty, however astandardized method has not been yet achieved. This paper makes an analysis of the variouselements to be considered when choosing a specific approach: in the implementationuncertainty of circular features. The most common manufacturing signatures affectingcircular profiles were considered, together with the number of points necessary for areliable estimation of implementation uncertainty.

The solid flow in air-catalyst in circulating fluidized bed was simulated with CFD model to obtain axial and radial distribution. Therefore, project parameters were confirmed and steady state operation condition was improved. Solid holds up axial end radial profiles simulation and comparison with gamma transmission measurements are in a good agreement. The transmission signal from an 241Am radioactive source was evaluated in NaI(Tl) detector coupled to multichannel analyzer. This non intrusive measuring set up is installed at riser of a cold pilot unit to determine parameters of FCC catalyst flow at several concentrations. Mass flow rate calculated by combining solid hold up and solid phase velocity measurements was compared with catalyst inlet measured at down-comer. Evaluation in each measured parameter shows that a relative combined uncertainty of 6% in a 95% interval was estimated. Uncertainty analysis took into account a significant correlation in scan riser transmission measurements. An Eulerian approach of CFD model incorporating the kinetic theory of granular flow was adopted to describe the gas–solid two-phase flows in a multizone circulating reactor. Instantaneous and local gas-particle velocity, void fraction and turbulent parameters were obtained and results are shown in 2 D and 3D graphics.

The grazing incidence X-ray reflectivity is used to determine the multilayer thickness ofGaAs/AlAs supperlattice. The measurement process includes the fitting model and themeasurement conditions (different powers of 45 kV × 40 mA, 40 kV × 40 mA and 35 kV × 40mA, different step sizes of 0.005°, 0.008° and 0.010°,and different times per step of 1 s, 2 s, 3 s). In order to obtain the valid measurementprocess, the combined standard deviation is used as the normal of the fitting resultsselection. As a result, the measurement condition of 0.008° step size and 2 stime per step with the power 40 kV × 40 mA is selectable with the operation stability offacilities and smaller error.

This paper presents a joint use of the T2 chart and total inertial tolerancingfor process control. Here, we will show an application of these approaches in the case ofthe machining of mechanical workpieces using a cutting tool. When a cutting tool inmachining impacts different manufactured dimensions of the workpiece, there is acorrelation between these parameters when the cutting tool has maladjustment due to badsettings. Thanks to total inertial steering, the correlation structure is known. Thispaper shows how T2 charts allow one to take thiscorrelation into account when detecting the maladjustment of the cutting tool. Then thetotal inertial steering approach allows one to calculate the value of tool offsets inorder to correct this maladjustment. We will present this approach using a simpletheoretical example for ease of explanation.

In this paper, we describe techniques for evaluating the uncertainties associated with the assessment of form error, i.e., the departure from ideal geometry of a manufactured part, in coordinate metrology. The techniques take into account measurement uncertainty, sampling effects due to the fact that the form error is determined from a finite set of coordinate data points, and the spatial correlation of the form errors. The techniques are designed to be practical, without the need for complex computation.

This work presents the results of a survey carried out among Brazilian calibrationlaboratories accredited under ISO/IEC 17025:2005 with the objective to identify how theselaboratories investigate the root causes of unsatisfactory results in proficiency testing.The survey was coordinated by the Brazilian accreditation body, the General Coordinationfor Accreditation (Cgcre), of the Institute of Metrology, Quality and Technology(Inmetro).

Manufacturing of high-quality components and assemblies is clearly recognised byindustrialised nations as an important means of wealth generation. A “right first time”paradigm to producing finished components is the desirable goal to maximise economicbenefits and reduce environmental impact. Such an ambition is only achievable through anaccurate model of the machinery used to shape the finished article. In the first analysis,computer aided design (CAD) and computer aided manufacturing (CAM) can be used to producean instruction list of three-dimensional coordinates and intervening tool paths totranslate the intent of a design engineer into an unambiguous set of commands for amanufacturing machine. However, in order for the resultant manufacturing program toproduce the desired output within the specified tolerance, the model of the machine has tobe sufficiently accurate. In this paper, the spatial and temporal sources of error andvarious contemporary means of modelling are discussed. Limitations and assumptions in themodels are highlighted and an estimate of their impact is made. Measurement of machinetools plays a vital role in establishing the accuracy of a particular machine andcalibrating its unique model, but is an often misunderstood and misapplied discipline.Typically, the individual errors of the machine will be quantified at a given moment intime, but without sufficient consideration either for the uncertainty of individualmeasurements or a full appreciation of the complex interaction between each independentlymeasured error. This paper draws on the concept of a “conformance zone”, as specified inthe ISO 230:1 – 2012, to emphasise the need for a fuller understanding of the complexuncertainty of measurement model for a machine tool. Work towards closing the gap in thisunderstanding is described and limitations are noted.

This paper describes the methodology of the compatibility criteriaEn and the methodology of repeatabilityand reproducibility (R&R) throught the average and range method. With this paperwe will use the methodology R&R for the evaluation of the compatibility criteriabetween the staff of the laboratories, where independent measurements are not insured.

The paper gives a brief description of the principles and the uncertainty of the acousticcalibration methods that today are applied by National Metrology Institutes andcalibration service centers. Even if some of the calibration principles have been appliedover more than half a century, the methods and the instrumentation are still being refinedin order to minimize their uncertainty, to extend their frequency ranges, to include extraparameters and to speed up slow processes. In addition to the traditional methods formicrophone sensitivity and frequency response calibration, new development areas, like forexample wind power, has created needs for low-frequency and infra-sound calibration, downto 0.1 Hz. Other high-tech areas have lead to the development of methods for phaseresponse comparison calibration of microphones for large arrays, for sound intensitymeasurement and for verification of dynamic linearity of microphones at very high soundpressure levels, up to about 174 dB that corresponds to 10 kPa.

Treatment of experimental data often entails fitting frequency functions, in order todraw inferences on the population underlying the sample at hand, and/or identify plausiblemechanistic models. Several families of functions are currently resorted to, providing abroad range of forms; an overview is given in the light of historical developments, andsome issues in identification and fitting procedure are considered. But for the case offairly large, well behaved data sets, empirical identification of underlying distributionamong a number of plausible candidates may turn out to be somehow arbitrary, entailing asubstantial uncertainty component. A pragmatic approach to estimation of an approximateconfidence region is proposed, based upon identification of a representative subset ofdistributions marginally compatible at a given level with the data at hand. Acomprehensive confidence region is defined by the envelope of the subset of distributionsconsidered, and indications are given to allow first order estimation of uncertaintycomponent inherent in empirical distribution fitting.

In order to determine mechanical properties of materials various kind of tests can be applied by means of using their tensile strength, lower yield stress, proof stress, impact strength, Brinell, Rockwell and surface hardness, elongation after fracture properties. Among these tests, three point flexural testing method has some advantages such as easy preparation (production) of samples and no gripping problems comparing to tension test. Flexural tests results should be obtained accurately to provide expected testing performance. The measurement uncertainty of flexural tests should be calculated by conducting all effective uncertainty parameters during the test procedure. In this study, the measurement uncertainty of the flexural test of ABS (Acrylonitrile Butadiene Styrene) material was investigated, which is widely used as industrial plastic material in many applications.

A free-space transmission method has been used for reliable shielding effectivenessmeasurement of the easily available textile materials. Textiles with three different yarndensities were studied for their shielding effectiveness with the help of a vector networkanalyzer and laboratory calibrated two X-band horn antennas. The expressions ofuncertainty estimation have been derived in accordance with the present free-spacemeasurement setup for the calculated SE values. The measurements have shown that anelectromagnetic energy can be maximum shielded up to 16.24 dB with measurement uncertaintyless than 0.21 dB in 8.2 to 12.4 GHz range by a 160.85 μm textile. Thus,a thin textile with a high density can have higher shielding and this property mainlydepends on its intrinsic structure, frequency range and thickness. This study promises thepotential applications of such materials as a very cost effective shielding material atmicrowave frequencies with some modifications.

Since 2006, the wood preservation laboratory of Cirad is accredited by COFRAC (French accreditation committee – accreditation No. 1-1686) for tests on the durability of wood and wood-based products and on protective efficacy of wood preservatives and termite control products. The metrological approach adopted by the wood preservation laboratory is a key factor on the continuous improvement of practices. Tests to determine the resistance against wood-destroying biological agents are the most difficult of all wood analysis tests. They are aimed at assessing and quantifying the impact of living organism, such as fungi and termites, on a lignocellulosic material. The extent of variability of this impact, which in turn is linked with the diversity of these organisms and of the material, can be readily determined. The validity and reliability of the findings therefore depend directly on the quality of the metrological process, including the choice of measurement devices, their management and compliance with international standards.

The geometric measurement of parts using a coordinate measuring machine (CMM) has beengenerally adapted to the advanced automotive and aerospace industries. However, for thegeometric inspection of deformable free-form parts, special inspection fixtures, incombination with CMM’s and/or optical data acquisition devices (scanners), are used. As aresult, the geometric inspection of flexible parts is a consuming process in terms of timeand money. The general procedure to eliminate the use of inspection fixtures based ondistance preserving nonlinear dimensionality reduction (NLDR) technique was developed inour previous works. We sought out geometric properties that are invariant to inelasticdeformations. In this paper we will only present a systematic comparison of somewell-known dimensionality reduction techniques in order to evaluate their accuracy andpotential for non-rigid metrology. We will demonstrate that even though these techniquesmay provide acceptable results through artificial data on certain fields like patternrecognition and machine learning, this performance cannot be extended to all realengineering metrology problems where high accuracy is needed.