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Conference Proceedings 2016 (47)

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Picture of the productA Review of In-situ Temperature Measurements
A Review of In-situ Temperature Measurements for Additive Manufacturing Technologies
Ryan Murphy, Sandia National Laboratories
Additive manufacturing (AM) encompasses a rapidly advancing host of technologies used for building parts with complex geometrical shapes layer-by-layer from a wide range of materials such as polymers, glasses, ceramics, metals, and metal-alloys. A wide variety of AM processes are used to build parts on test beds using processes such as material extrusion and laser or e-beam irradiation of powders and liquids, depending on the industrial or commercial application. Unfortunately the dimensional and compositional quality of AM built parts highly depends on the technology, and can even significantly vary between different AM machines of the same technology, due to a lack of process feedback and control. Improvements have been made by performing computational modeling and ex-situ characterization such as x-ray diffraction, focused ion beam cross-sectioning, x-ray computed tomography, and electron microscopy. These techniques, however, are time consuming, expensive, and do not allow in-situ monitoring of parts as they are built. In-situ temperature measurements are promising as they monitor the build temperature and can provide feedback for better process control. Thermal imaging is widely-used for in-situ temperature measurements, but is limited to qualitative data due to the unpredictability of emissivity as temperature and composition dynamically change. Two-color pyrometry and mm-wave radiometry measurements promise to circumvent these problems but have their own dimensional limitations. These methods and others will be compared and contrasted, and future improvements of in-situ temperature measurements will also be discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Certain commercial equipment, instruments, or materials are identified in this paper in order to adequately describe the experimental procedure. Such identification does not imply recommendation or endorsement by the authors, Sandia National Laboratories, or NCSL International, nor does it imply that the materials or equipment identified are the only or best available for the purpose.


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CP_16_4C_MURPHY
Picture of the productAssessing Your Laboratories Technical Competence
Assessing Your Laboratories Technical Competence in Regards to the Requirements of ISO/IEC 17025:2005, Section 5
Michael j. Kramer - Calibration Program Manager, Perry Johnson Laboratory Accreditation, Inc.
This will look at a practical and efficient way of assessing your laboratory's compliance to Section 5 of ISO/IEC 17025:2005. An assessment of Section 5 should consist of much more than just cross referencing requirements of the Quality Management System. This paper will provide an overview of each pertinent technical section of the standard and provide a hands on approach to assessing the laboratory's compliance to the elements of ISO/IEC 17025:2005. It will educate users on how to proactively uncover nonconformities which may arise when performing daily routine calibrations or tests. Each part of Section 5 will be reviewed and will include an interpretation of key elements, along with objective evidence in which internal auditors should request while actually witnessing the calibrations or tests being undertaken. This will incorporate a front door to backdoor approach from the acceptance of an artifact to the return of an artifact to a client. Key elements of Section 4 will also be discussed as applicable. This will benefit participants involved in the quality operation of a laboratory, particularly those designated to conduct or oversee internal audits and results.


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CP_16_KRAMER
Picture of the productBest Practices for Properly Using Thermometric Fixed-Point
Best Practices for Properly Using Thermometric Fixed-Point Cells as Calibration Reference Standards
Michael Coleman, Fluke Calibration
This paper discusses thermometric fixed-point cells and considerations for their use as International Temperature Scale of 1990 (ITS-90) defining standards for the calibration of Standard Platinum Resistance Thermometers (SPRTs). Designation as an ITS-90 defining standard is dependent on the chemical composition (e.g., purity) of the sample material, which in turn predicts the melting, freezing, or triple-point realization temperature of the material. However, sole knowledge of the chemical composition and purity of the sample used to construct a fixed-point cell does not guarantee a particular realization temperature. To establish traceability to the International System of Units (SI), the fixed-point cell must be compared to other fixed-point cells that are traceable to the SI - through National Metrology Institutes (NMI's) with internationally-accepted measurement capabilities. ISO/IEC 17025 outlines a method for establishing reference standard traceability, and accreditation bodies have required qualification of thermometric fixed-point cells for over a decade. However, the authors have observed that most fixed-point cells are not qualified, and many users do not realize the implications of using them without first establishing traceability. To better clarify these implications, this paper presents the main sources of fixed-point cell realization temperature errors and uncertainties, along with suggestions for handling these issues. References to current quality standards and industry best practices will also be presented, to underscore the current requirements for proper use of ITS-90 defining thermometric fixed-point cells.


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CP_16_3C_COLEMA
Picture of the productCalibration Due Dates - Daily or End of the Month?
Harry C. Spinks - Business Consultant, TechTrology LLC
Much of the test equipment in-use today requires periodic calibration. This is done to ensure a high probability that the equipment will remain in tolerance by the due date or end of the calibration interval. The majority of calibration intervals are monthly with common intervals every 3 months (3, 6, 9, 12, etc.) The calibration interval is based on many factors which this paper will not address. But when, exactly, should the equipment be due? And by due calibration, we mean that it is taken out of service to be calibrated. The purpose of this paper is to examine when (specifically) the equipment is required to be removed from service for calibration. Two of the most popular methods is the day of the month (daily) and end of month due date. But which is better for you? This paper will examine the pros and cons of each method so you can decide which is best for your situation.


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CP_16_SPINKS
Picture of the productCalibration in Regulated Industries
Calibration in Regulated Industries: Federal Agency Use of ISO/IEC 17025 and ANSI/NCSL Z540.3
Paul Reese, Baxter Healthcare Corporation
ANSI/NCSL Z540.3-2006 and ISO/IEC 17025:2005 are voluntary consensus standards which prescribe requirements for the calibration of measuring and test equipment and for the technical competency of the performing laboratories. Many agencies in the U.S. which are part of, or regulated by, the Federal Government are required to use instruments which have been calibrated in accordance with one or both of these standards. The National Technology Transfer and Advancement Act (NTTAA) of 1995 compels all federal agencies to use technical standards that are developed by consensus standards bodies, in lieu of "government-unique" standards. ISO 17025 and ANSI Z540.3 have evolved over a half-century of metrological advancement, drawing upon expertise in the public and private sector. They are now supported by a mature infrastructure that facilitates mutual recognition and global trade, ensuring calibrations are accepted worldwide. However, some federal agencies and regulatory bodies in the U.S. have not yet adopted these standards. Calibrations are routinely performed on instruments, utilized in some government-regulated industries, which may not conform to these requirements. This paper discusses risks imparted to products and services produced in such environments. Particular focus is given to the Food and Drug Administration's (FDA) regulation of calibration requirements in the Quality System Regulation (QSR) found in Title 21 of the Code of Federal Regulations (CFR). Currently, a paucity of official guidance exists with respect to what constitutes an acceptable calibration program in medical device and pharmaceutical industries. Ambiguities persist due to lack of agreement upon voluntary consensus standards such as ISO 17025 and ANSI Z540.3. Fundamental requirements such as traceability, measurement uncertainty, measurement decision-rules, as well as basic metrological definitions are ill-defined in the CFR. The objective of this paper is to provide relevant background information and to encourage constructive dialogue between government agencies, standards writing committees, industry partners, and third party assessment/accreditation bodies. Cooperation of this type is consistent with public law and White House policy objectives. Ultimately, such dialogue may foster agreement on the use of these voluntary consensus standards for calibration in regulated industries, resulting in improved quality and reduced risk to consumers and patients.


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CP_16_6D_REESE
Picture of the productCalibration of Electro-Cardio Graph Simulators
Dr. Steven Yang, Electronics Engineer, Standards and Calibration Laboratory
The Standards and Calibration Laboratory (SCL) in Hong Kong has set up a calibration facility for electro-cardio graph (ECG) simulators. ECGs are medical devices designed to measure the electrical signals associated with cardiac activity. They are used to diagnose heart diseases and arrhythmias, which are commonly used in hospitals, emergency facilities and medical institutes. Routine performance check of ECGs could be performed by ECG simulator. In order to ensure the accuracy of the instruments, calibration procedures which are traceable to primary standards or SI units are essential. At the SCL, the output signal from an ECG simulator is measured by a differential amplifier and a high speed digital sampling system. The system also includes a reference voltage source, an inductive voltage divider and a control computer. Digital sampling system enables the calibration of non-sinusoidal wave with high accuracy. Signal characteristics including signal amplitude, frequency and wave form could be evaluated by an in-house developed program for normal sinus rhythm waveforms as well as for ECG performance waveforms (sinusoidal, triangle, square and pulse). Since the test signal is in the sub-millivolt (mV) range, a differential amplifier with high common mode rejection ratio is used to amplify the test signal. The frequency response of the differential amplifier is calibrated by a reference voltage source and an inductive voltage divider, whereas the digital sampling system is calibrated against the laboratory's voltage and frequency reference standards. The developed calibration system is capable of measuring signals in the sub-mV level with test uncertainty ratio (TUR) better than 4. Details of the system configurations and the uncertainty evaluation will be described in the paper.


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CP_16_9D_YANG
Picture of the productCalibration of Infrasound Measurement Devices
Michael Mende - Physicist, SPEKTRA Schwingungstechnik und Akustik GmbH
Infrasound measurement devices like low frequency microphones and dynamic pressure sensors are widely used in many branches of trade like aerospace industries (airflow mechanics) or acoustical engineering (infrasound measurements of geophysical events, emissions of wind energy plants, etc.). This paper presents a calibration system that allows the calibration of such devices in a frequency range as low as 0.1 Hz to 31.5 Hz. It is based on a special low frequency pressure chamber that uses a similar working principle as a pistonphone but is adapted to the requirements of this low frequency range. The chamber has a size that allows to place the whole device under test (DUT) inside the chamber. So no mechanical adaption between DUT and pressure chamber is required and thus the DUT can have a nearly arbitrary shape. Other than a pistonphone which is based on the assumption that the sound level can be calculated from the physical dimensions of the chamber by means of the adiabatic gas law, this calibration system requires the use of a reference standard sensor. This is due to the fact that in the low frequency range the gas compression becomes more and more an isothermal process the lower the applied frequency gets. Thus a pressure sensor is used as reference standard allowing high precision measurements (uncertainty < 0.05 dB). The paper discusses the question how the measurement uncertainty over the whole frequency can be determined although the reference pressure sensor is only calibrated by static pressure calibration. It also shows how other parameters like the homogeneity of the pressure field can be determined that contribute to the measurement uncertainty. Finally some calibration results will be presented.


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CP_16_MENDE
Picture of the productCalibration of Optical Fiber Time Domain Reflectometers
Calibration of Optical Fiber Time Domain Reflectometers in Accordance with IEC 61749-1:2009
Samuel Ko, Electronics Engineer, Standards and Calibration Laboratory
Optical time domain reflectometers (OTDR) are widely used in testing, installation and maintenance of optical communication networks. An OTDR launches a series of high speed pulses into a fibre network and measures the amplitude and the delay time of reflected signals to locate events or faults along a fibre link. Precise measurement capabilities of an OTDR on distance, loss/attenuation and reflectance are required to locate and evaluate the severity of faults accurately. The Standards and Calibration Laboratory (SCL) has developed a calibration system for calibrating single mode OTDRs fitted with FC connectors at wavelength 1310 nm and 1550 nm in accordance with the international standards IEC 61746-1:2009. The characteristic parameters calibrated include the distance deviation, attenuation deviation and reflectance deviation. The principle of the calibration is to apply a set of reference standards, namely distance calibration artifact, attenuation calibration artifact and reflectance calibration artifacts, to the OTDR, and to compare against the displayed values for a given OTDR setting. The distance calibration artifact consists of a recirculating delay line and of a lead-in fiber which generates a series of reflection peaks separated by calculable distances. The linear regression of the measured data is processed in Microsoft Excel to estimate the distance scale deviation and zero location offset. The attenuation artefact consists of a G.652 fibre spool with known spectral attenuation and attenuation uniform. The reflectance artifact is composed of a set of known reflectances ranging from -10 dB to -50 dB. The best measurement uncertainties for the distance, attenuation and reflectance deviation calibration are 2m, 0.06 dB and 1.7 dB respectively.


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CP_16_9C_KO
Picture of the productCharacterization of the NIST Magnetic Suspension Mass Comp.
Characterization of the NIST Magnetic Suspension Mass Comparator Apparatus and Facility
Edward Mulhern, National Institute of Standards and Technology (NIST)
With the upcoming redefinition of the kilogram set for 2018, National Metrology Institutes are working to identify and reduce uncertainties related to the realization and dissemination of the kilogram. In the current system the kilogram is equal to the mass of the International Prototype Kilogram (IPK) with zero uncertainty. In the "New SI", the Watt Balance and Avogadro Experiment will use a fixed value of Planck's constant (zero uncertainty) and realize the kilogram based on that fixed value. The previous uncertainty associated with Planck's constant will essentially be transferred to the kilogram. In addition, the new realization will occur under vacuum and new sources of uncertainty in the dissemination to air will have to be accounted for.
At the National Institute of Standards and Technology, the Mass and Force group is developing a unique system for disseminating the kilogram realized in vacuum to air where customers can continue their usage of calibrated masses without affect. Currently, the widely accepted method for vacuum-to-air dissemination involves making measurements in both environments and then building an empirical model to account for the sorption of particles when transferring between vacuum and air. At NIST, a magnetic suspension mass comparator (MSMC) is utilized in order to directly compare a mass in vacuum to a mass in air.
In order to meet customers needs it is vital that the uncertainty in our MSMC measurement is well understood so that it can be accounted for. Contributing to the overall uncertainty are uncertainties in the measurement environment, in the suspension apparatus and in the measurement facility itself. To accurately characterize this process, the Mass and Force group has measured the gravitational gradient along the measurement axis, the vibrations of the lab floor and the ambient temperature and humidity stability of the room. Additionally, we have worked to model the stray magnetic fields emanating from the MSMC. This talk will detail the methodology and results of these characterization efforts and explain how each factor influences the final uncertainty budget.


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CP_16_7C_MULHER
Picture of the productCombined Instruments for Test Efficiency
Tim Coonan - Software Engineer, National Instruments Corporation
An instrument combination is when two or more separate instruments are combined into a system to achieve a single function. Examples are a DC Source inline characterized by a high precision DMM to create a high precision DC source or two CW Sources and a combiner used to create a TOI test instrument. Often times calibration procedures are written to use an expensive and slow multifunction calibrator that is not optimized for time and cost. In this paper I will describe examples of when we have replaced a multifunction calibrator with a more specific instrument combination in order to optimize the procedure, what we had to look out for while making these replacements, and how we have designed our hardware abstraction layer to allow for these replacements without the need to update test code.


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CP_16_COONAN
Picture of the productComparative Calculations to Evaluate Proposed Changes to GUM
Russell Geisthardt - Keysight Technologies
An ongoing effort is underway to revise the Guide to the Expression of Uncertainty in Measurement (GUM). The initial draft in early 2015 was met with intense scrutiny, however understanding the proposed changes from an implementation standpoint is important even if the new method is only partially adopted. The current proposal, removes reference to effective degrees of freedom as calculated by the Welch-Satterthwaite formula. The move to evaluate Type A components of uncertainty using Bayesian statistics represents a departure from traditional GUM methodology. To understand better the pros and cons of the proposal, this paper will present a series of examples showing the traditional method of evaluating data verses the Bayesian approach. The results are then employed in the evaluation of uncertainty using both Linear and Monte Carlo propagation to show the how the new approach changes the output. Combinations of different probability distributions with different relative sizes, and different equations are used to help the reader better analyze and evaluate the impact of such a change.


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CP_16_6C_GEISHA
Picture of the productComputer Aided Calibration of Voltage and Current Surge Gen.
Computer Aided Calibration of Voltage and Current Surge Generator in Accordance with IEC 61000-4-5:2014
Samuel Ko - Electronics Engineer, Standards and Calibration Laboratory
Reliable electrical and electronic equipment are designed to immense against different kinds of electromagnetic interference such as voltage dip, burst, electrostatic discharge, and surge. Surge is a 'slow transient overvoltage' with frequency contents below 10 MHz which may cause electrical and thermal damages to the equipment. Surges are created by switching events and insulation faults in AC power distribution networks, lightning and others. A combination wave generator which simulates the switching and lightning transients is used to evaluate the immunity performance of equipment under test against high energy surge interference. The Standards and Calibration Laboratory (SCL) has recently set up a system to calibrate 1.2/50 μs - 8/20 μs or 10/700 μs - 5/320 μs combination wave generators by laboratory digital oscilloscope in accordance with the latest international standard IEC 61000-4-5:2014. The new revision has made many significant changes including redefinition of the surge waveforms and the evaluation of measurement uncertainty. The calibration parameters include the front time, duration and voltage surge peak. The principle of the calibration is to convert the high voltage or high current surge pulse waveform to lower signal waveform by calibrated potential divider or burden respectively. System response time including the oscilloscope, divider and the burden must be considered to characterize the surge waveform accurately. The required voltage and timing measurement is taken by computer automatically to reduce human error and to enhance consistency. The best measurement uncertainties of the front time, duration and surge peak are 5%, 2% and 3% respectively with test output voltage of 0.5 to 4 kV.


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CP_16_KO
Picture of the productConformance Decision Rules to Support ISO/IEC CD 17025
Conformance Decision Rules to Support ISO/IEC CD 17025 Under Revision
Robert Stern, Keysight Technologies
The current draft of ISO/IEC CD 17025 contains a clause to document the decision rule for conformity along with the risk and statistical assumptions in the test method or procedure (7.1.1d). So how shall we do this? A common strategy for managing measurement decision risk is to choose a guard-band that results in a desired false-accept risk given a tolerance limit, the calibration process uncertainty, and the a priori probability. JCGM 106:2012 provides guidance for the implementation of prior knowledge in conformance decisions, however a good estimate of the a priori probability may be difficult to obtain. Historical device population information for estimating a priori probability may not be readily available such as "testing" applications where the device is a prototype. This paper presents the false-accept risk and corresponding false-reject risk for four decision rules. We provide simple equations to limit risk to pre-determined amounts. Several case studies illustrate when to use "Specific" or "Global" risk. When "Global" risk is appropriate, the decision rules can be applied with limited knowledge of a priori probability.


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CP_16_8D_STERN
Picture of the productDesign and Construction of the In-Vacuum Mass Exchange Sys.
The Design and Construction of the In-Vacuum Mass Exchange System for the Realization and Dissemination of the New SI Unit of Mass
Leon Chao, National Institute of Standards and Technology (NIST)
The international system of units will complete a transition in 2018 from a system based on seven fundamental units to a system of seven fundamental constants. More specifically, regarding the SI unit of mass, the kilogram (kg) will be realized in terms of a fixed value of the Planck constant. At the National Institute of Standards and Technology, a watt balance will be used to relate the kilogram to the Planck Constant. One major challenge introduced with this new definition involves the environment where the realization occurs.

In traditional mass metrology, all comparisons are completed in air and a chain of traceability can be completed back to the International Prototype Kilogram using conventional mass balances. In the new SI, the watt balance will be operated under vacuum. The vacuum environment is important for multiple reasons, including the elimination of the buoyancy correction and the introduction of sorption effects if the artifacts are transferred from vacuum to air.

In order for the mass community to utilize the new vacuum-based definition in air, the scientists in the Mass and Force Group are constructing a magnetic suspension balance. This experiment will allow comparison of a mass in vacuum from the watt balance to an artifact in air that will be used for dissemination. This vacuum-to-air transfer is only worthwhile if the artifacts in the watt balance can be transferred to other instruments without breaking vacuum.

To solve this problem, a complete, custom vacuum transfer system was developed for mass artifacts. The system is comprised of a series of load locks, mass exchange points and vacuum transfer arms to connect the mass transport vehicle to each experiment. Each stage of mass transfer introduces new challenges including material selection of artifact handlers, strict component design constraints and the logistics of maintaining a clean, reproducible vacuum environment during transfers that can span 100 meters of labs and hallways. This paper will explain the growing importance of vacuum technology in mass metrology and discuss how each of the aforementioned design problems were solved to create the vacuum transfer system in place today.


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CP_16_3B_CHAO
Picture of the productDesign of a Table-top Watt Balance
Stephan Schlamminger PhD, National Institute for Standards and Technology (NIST)
For some time, watt balances have been used at National Metrology Institutes (NMI) to determine the precise value of the Planck constant. In the future, these devices can be used to realize the unit of mass from a fixed value of the Planck constant in the revised International System of Units. Typically, these NMI watt balances employ masses of 1 kg and their measurements have assigned relative uncertainties on the order of a few parts in 100 million. Building and operating these instruments is intensive and requires significant resources. We believe that it is worthwhile to build a smaller, table top watt balance with a capacity of up to 10 g and a relative uncertainty goal of 1 part per million. Increasing the relative uncertainty by a factor of 100 makes the measurement much easier - for example by eliminating the need to have a separate device for the precision measurement of the local gravitational acceleration. Yet a mass measurement with a relative uncertainty of 1 part per million is competitive with the calibration uncertainty of current E2 masses at the 1 g level. In the new SI, a table top watt balance could enable direct traceability of small masses to electrical units without having to compare the small mass to the nation's prototype. This will significantly shorten the calibration chain and is useful to primary calibration laboratories and industry. We investigate several different geometries for a table top watt balance including variations of the permanent magnet design and two different systems to compare the weight to the electromagnetic force. For each of the geometries we discuss the practicality in the field and the leading systematic uncertainties.


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CP_16_7B_SCHLAM
Picture of the productDesign of Digital Controllers for Electromagnetic Force
Design of Digital Controllers for Electromagnetic Force Compensated Balances Focused on the Disturbance Transfer Function
Norbert Rogge, Technische Universitat Ilmenau
The main objective of the paper is to propose a new possible design process for controllers in electromagnetic force compensated balances (EMFC). Controllers used in EMFC balances demand a high precision of the measured and generated electrical quantities. Regarding to the achievable uncertainty in static measurements, EMFC balances are state of the art, but in future applications the importance of dynamic applications will probably increase. Therefore the controlled system should possess a high measurement bandwidth to reduce the measurement time in dynamic applications. For digital controller concepts this results in ambitious requirements on the controller hardware especially on the digital-to-analog and analog-to-digital converters. The paper will illuminate the limitations caused by commercial off-the-shelf standard hardware and propose a possible alternative hardware concept. A design process will be presented, which is strongly focused on the disturbance transfer function of the control loop. This can be achieved by building a detailed model of the balance behavior, in particular by modeling the disturbance sensitivity. Based on the consideration of these additional system characteristics in the controller design process, the measurement time of the balance is reduced significantly compared to conventional PID controllers. By using a specially developed controller hardware environment, this is also achievable with a low static uncertainty of the controlled balance.


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CP_16_7B_ROGGE
Picture of the productDimensional Fidelity of Replica Casting Compound
Edward O'Brien, R&D S&E, Electrical Engineering, AC Laboratory / Sandia National Laboratories
Difficulty arises when wanting to measure features on a part or assembly that is inaccessible with measuring equipment. Sometimes, these features are small and in a recess, such as an O-ring groove; other times, the feature is on a complete assembly which is large, such as a valve seat on an engine. A common practice is to use a replica casting compound to make a negative impression of the feature of interest and measure the replica. Advantages of making replicas include being able to;

    (1) measure a small imperfection on a large piece without having to disassemble or destroy the original
    (2) provide archiving of such imperfections
    (3) eliminate light scattering which might cause difficulty with some optical techniques for dimensional metrology

Reprorubber®, a metrology-grade casting material, is a commonly used silicone-based replica casting compound made from polyvinyl siloxane (PVS). We investigated the fidelity to which this material replicates surface texture and geometry, using step height reference specimens and parameter reference specimens (Type A per ASME B46.1:2009), along with the fidelity for longer spatial wavelength features using optical flats (and Type C specimens per ASME B46.1:2009), and other surfaces with known form geometry. Results of step heights are presented here, but all results will be presented at the conference. Our results are used to assign a Type B uncertainty associated with the replication process when replicating a feature which is inaccessible to dimensional instruments.


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CP_16_6B_OBRIEN
Picture of the productExpand Capacitor and Inductor Frequency Range
Expand Capacitor and Inductor Frequency Range Using a Dependent Correction
Dimaries Nieves - Senior Metrology Engineer, National Instruments Corporation
Impedance is the opposition to alternating current flowing in an electric circuit or component. Impedance is expressed in basic circuit elements that include resistance (R), inductive reactance (XL), and capacitive reactance (XC). Real-world components are made up of wires, connections, conductors and dielectric materials combine to make up the impedance characteristics in a circuit. Impedance can change due to signal frequency and voltage level, the presence of a DC bias voltage or current and environmental factors such as operating temperatures or altitude. Of these potential influences signal frequency is often the most significant factor.

Most commercial LCR bridges and meters have the capability to make measurements with selectable test frequencies. This feature is important because to obtain accurate measurement results the test frequency should be very close to the desired operational frequency. National Measurement Institutes typically provide traceable values at 1 kHz and 100 Hz, as default option. In order to use a capacitor or inductor over its entire frequency range an additional process is needed.
This paper describes a method to determine and use a frequency correction factor to calculate the actual capacitance or inductance values over their entire frequency range using a commercial LCR bridge. Calculation of the uncertainty component associated to the frequency correction factor is included as well as the effect in the calculations of the capacitor or inductor accuracy.


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CP_16_NIEVES
Picture of the productExtending Oscilloscope Bandwidth Calibrations to 27GHz
Paul Roberts - New Product Development, Fluke Calibration
Until recently, finding a convenient solution for oscilloscope bandwidth calibrations above 6GHz using levelled sinewaves was problematic, currently the highest frequency provided by oscilloscope calibrators. Imputing equivalent bandwidth from a fast edge rise time measurement is possible (to around 15GHz with the fastest calibrator 25ps risetime edge), but may be impractical or inappropriate. Alternatively, users often resort to the added complexity of a high frequency signal generator, power splitter and power meter. A new RF calibrator greatly speeds up and simplifies oscilloscope bandwidth testing up to 27GHz. This paper overviews oscilloscope calibration, including levelled sine and fast pulse bandwidth testing methods, and describes how such an RF calibrator may be used alongside dedicated oscilloscope calibrators or other multi-product calibrators with oscilloscope calibration options. Considerations for placing trigger signal pick-off devices inside the RF calibrator's automated digital levelling loop and also evaluating and combining mismatch errors are discussed.


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CP_16_7C_ROBERT
Picture of the productImpact of BIPM Amendments in the Romanian Mass Dissemination
Dr. Adriana Vâlcu - Dr. Engineer, National Institute of Metrology
From January 2014 to January 2015 an extraordinary calibration using IPK was carried out at BIPM. After this calibration campaign, it was concluded that the results obtained for the set of working standards indicate the existence of an offset from the IPK over 22 years by 35 μg. Therefore, Consultative Committee for Mass and Related Quantities (CCM) recommended that all mass calibrations of national prototypes and of mass standards issued by the BIPM during the years 2003-2013 need to be amended with this value. During this period, Romanian National Prototype of the Kilogram (NPK ) together with stainless steel kilogram Ni81 were calibrated two times at BIPM: in 2005 and 2013.

After receiving the BIPM amendments, the first measure taken by Mass laboratory was to perform the comparison between NPK and stainless steel reference standards, which represents the main step in the dissemination of mass unit in Romania.
The paper describes the results obtained from this comparison, the impact of these new values on Romanian mass dissemination and actions taken in consequence.


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CP_16_VALCU
Picture of the productImpact of Pressure and Temperature upon the Modern Football
Kevin Radzik, Lead Scientist and Operations Manager, Alliance Calibration
Given the recent controversies within the arena of modern sports and the rules of fair play in the NFL Alliance Calibration will investigate the impact of inflation and temperature upon the compressibility of the modern football based upon the published NFL specifications. Moreover, the goal of this study will be to determine the impact upon gripping and control of the modern football under the varied conditions. Testing will be based upon applicable ISO-17025 standards and will follow the DMAIC process. Alliance Calibration will study the effect of different levels of pressure and temperature upon a regulation NFL football. The testing will include the Calculated Measurement of Uncertainty (CMC) for measurement of compressibility as impacted by pressure (PSI) and temperature (degrees F) as part of the Design of Experiment.


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CP_16_3C_RADZIK
Picture of the productImplementation of the New Defense Standard VG 96910
Implementation of the New Defense Standard VG 96910 Documentation of Calibration Services
Gerhard P. Mihm - Project Manager; Test & Measurement Equipment & Calibration, Germand Armed Forces Calibration Organization
International military agreements and standards are published in Standardisation Agreements (STANAG). STANAG 4704 contains the minimum requirements for calibration (reference to ISO 17025) but also standard documents for the user of the t&m equipment. This STANAG has been developed further into the new German Defense Standard VG 96910 (Documentation of Calibration Services) by German Standards Institution (DIN) published 1. September 2015.
According to VG 96910 the holder of a test & measurement equipment has to define the calibration services needed before placing a calibration order. This requirement will also change the way of procurement of test & measurement equipment not only within the German Armed Forces. Before placing an order for purchasing test & measurement equipment, the measurement requirements have to be defined properly in accordance with ISO 10012. This will leed to the creation of a datasheet for the test & measurement equipment to be purchased. The retailer / distributor has to demonstrate the fulfillment of the required specification within the calibration certificate of the test & measurement equipment on offer and the traceability to national standards. The first calibration of the item after receiving can be considered as the conformity testing of the test & measurement Equipment to the required specification. This calibration will be continued to ensure that the test & measurement equipment can be used for the designated task. The Review of the calibration results can be used in accordance with RP-1 to define the calibration interval.


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CP_16_MIHM
Picture of the productInfluence of Adapters on AC-DC Difference Measurements
Dr. Stefan Cular, National Institute of Standards and Technology (NIST)
Electrical connector adapters, especially for inter-series connections, play a pivotal role in calibrations of electrical standards and devices. The conventional wisdom of using as few adapters as possible certainly is valid; however, this paper quantifies the influence of common co-axial adapters on voltage measurements up to 100 MHz. Measured values show that a single adapter can result in a voltage error of up to 3.5 %, while measurement uncertainty is estimated to be 0.2 % (k = 2) without factoring in the adapter. Results based on AC-DC and RF-DC voltage difference measurements are presented for inter-series connections of BNC, N-type, and GR874 series connectors. Adapter length was found to be nearly independent of connector series, and a generalized empirical model was generated based on the test frequency and adapter length. The model was validated with beaded airlines of varying lengths. Preliminary results indicated the proposed model can be used as an initial estimate of the error introduced by an adapter; however, additional testing of adapters of different materials and types is required prior to accepting such a generalized approximation. Additionally observations of wear characteristics and general repeatability are presented for consideration.


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Picture of the productIntegrating a CMM into an Engineering Technology Class
Integrating a CMM into an Engineering Technology Class Utilizing Simulation and Hardware
Joseph Fuehne PhD, Purdue Polytechnic Columbus
While most would consider learning to program a coordinate measuring machine (CMM) to be a skill best learned in a one week tutorial format training class, the Purdue Polytechnic in Columbus has integrated these skills into a semester-long class that treats the CMM as a tool to satisfy a mechanical design objective. The class is titled "Inspection and Validation of Product Design" and features six projects throughout the semester along with various lessons on geometric dimensioning and tolerancing. Each of the projects requires the student to create an assigned solid model using a computer aided design (CAD) tool from a drawing. Each student then has the model manufactured using a three-dimensional rapid prototyping machine (3D printer). The CAD models are then imported into the CMM programming and simulation tool (Calypso) for the students to design their measurement plan. Since the Purdue Polytechnic in Columbus has only one actual CMM (Zeiss Duramax), it is a great advantage to have 25 copies of the simulation software. Students can develop their measurement plans and practice and perfect them using the simulation tool. When they feel their measurement plan is satisfactory, the students load their CAD model and measurement plan into the computer attached to the hardware as well as secure the actual 3D printed part onto the hardware. Carefully using the hardware controls, the students then execute their measurement plans to determine how closely the 3D printing manufacturing process matched the nominal drawing dimensions. Later in the semester, assignments are added that include GD&T measurements such as circularity, flatness, perpendicularity, parallelism, runout and position tolerances. Over the course of the semester, students learn about the design process, prototyping, inspection, and validation while using the CMM as a tool for those lessons. This work includes detailed descriptions of the projects, the reports required for each project and the objectives of each project. There are also analyses of the 3D printing process and comparisons to a machining process in several projects.


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Picture of the productIntroduction to the Status of Interlaboratory Comparison
Introduction to the Status of Interlaboratory Comparison on Reference Photovoltaic Cell
Calibration at Center for Measurement Standards in Taiwan
Min An Tsai - Project Manager, Center for Measurement Standards/Industrial Technology Research Institute (CMS/ITRI)
Proficiency testing is one of the ways to evaluate the participant performance against pre-established criteria by means of interlaboratory comparisons. Center for Measurement Standards / Industrial Technology Research Institute (CMS/ITRI) has been committed to measurement technologies and statistical engineering. Thus, CMS has established its renowned reputation in metrology in Taiwan. Quality Engineering Department (QED) which belongs to Measurement Standards & Legal Metrology Division at CMS/ITRI is one of the designated organizations by Taiwan Accreditation Foundation (TAF) to hold proficiency testing in calibration field and act as the pilot for this interlaboratory comparison. For the photovoltaic (PV) field, the key quantity in the calibration of reference PV cells or modules is the short-circuit current of the device generated by a reference solar radiation with 1 kW m-2 total irradiance and with IEC 60904-3 AM1.5G reference solar spectral irradiance distribution. This paper introduces the status of interlaboratory comparison on primary reference solar cell calibration, including selection of the reference laboratory and assigned value, statistical analysis on comparative results, and criteria for performance evaluation, etc. The comparison includes one reference laboratory and two participating laboratories individually belonging to AIST,CMS/ITRI and FMI. The calibration method is conformed to IEC 60904-4:2009. En numbers are used as the performance statistics described in ISO/IEC 17043:2010.


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