Metrology Measurements Research Articles

Assessment of the state of the geometrical surface texture of seal rings by various measuring methods

The present paper concerns the metrological measurements of the geometric structure of the faces of seal rings made of silicon carbide and carbon-graphite. Three different instruments, i.e. the stylus profilometer, the optical profilometer, and the atomic force microscope, were used to measure the geometric structure of surfaces. In the comparative analysis, an identical area of the ring surface which was mapped by three measuring instruments with different sampling densities resulting from their metrological characteristics was assumed. The measurements made show that for the silicon carbide ring, the surface texture measurements on an atomic force microscope and optical instruments more accurately represent the actual topography than the measurement determined by the stylus profilometer.

Dual comb generation from a mode-locked fiber laser with orthogonally polarized interlaced pulses.

Ultra-high precision dual-comb spectroscopy traditionally requires two mode-locked, fully stabilized lasers with complex feedback electronics. We present a novel mode-locked operation regime in a thulium-holmium co-doped fiber laser, a frequency-halved state with orthogonally polarized interlaced pulses, for dual comb generation from a single source. In a linear fiber laser cavity, an ultrafast pulse train composed of co-generated, equal intensity and orthogonally polarized consecutive pulses at half of the fundamental repetition rate is demonstrated based on vector solitons. Upon optical interference of the orthogonally polarized pulse trains, two stable microwave RF beat combs are formed, effectively down-converting the optical properties into the microwave regime. These co-generated, dual polarization interlaced pulse trains, from one all-fiber laser configuration with common mode suppression, thus provide an attractive compact source for dual-comb spectroscopy, optical metrology and polarization entanglement measurements.

Measuring Recovery in Mental Health: Why the Next 100 Years of Occupational Therapy Practice Depends on Metrology and Meaningful Measurement

Abstract Date Presented 4/1/2017 In the United States and nations across the world, recovery is a priority for health care reform. Despite consensus for this model, little agreement exists about how to measure recovery. New approaches to measure recovery are summarized and strategies for instrument selection presented. Primary Author and Speaker: Skye Barbic

Computer training program for studying the method of testing soft magnetic materials

The question of the use of the computer training program when considering the methods for testing magnetic materials at high frequencies in the preparation of specialists metrologists is considered. Software simulator with the computerization of laboratory work used durin the study of the course “Methods and means of measurement” in the preparation of bachelors in the field “Metrology and Information and Measurement Technologies” is described.

Design of a dynamic biofilm imaging cell for white-light interferometric microscopy

In microbiology research, there is a strong need for next-generation imaging and sensing instrumentation that will enable minimally invasive and label-free investigation of soft, hydrated structures, such as in bacterial biofilms. White-light interferometry (WLI) can provide high-resolution images of surface topology without the use of fluorescent labels but is not typically used to image biofilms because there is insufficient refractive index contrast to induce reflection from the biofilm’s interface. The soft structure and water-like bulk properties of hydrated biofilms make them difficult to characterize in situ, especially in a nondestructive manner. We build on our prior description of static biofilm imaging and describe the design of a dynamic growth flow cell that enables monitoring of the thickness and topology of live biofilms over time using a WLI microscope. The microfluidic system is designed to grow biofilms in dynamic conditions and to create a reflective interface on the surface while minimizing disruption of fragile structures. The imaging cell was also designed to accommodate limitations imposed by the depth of focus of the microscope’s objective lens. Example images of live biofilm samples are shown to illustrate the ability of the flow cell and WLI instrument to (1) support bacterial growth and biofilm development, (2) image biofilm structure that reflects growth in flow conditions, and (3) monitor biofilm development over time nondestructively. In future work, the apparatus described here will enable surface metrology measurements (roughness, surface area, etc.) of biofilms and may be used to observe changes in biofilm structure in response to changes in environmental conditions (e.g., flow velocity, availability of nutrients, and presence of biocides). This development will open opportunities for the use of WLI in bioimaging.

Metrological aspects of reverse engineering of standardized products

The aim of the work is the development of an algorithm of reverse engineering for standardized products. To create metrological models, and even more to solve the complex task of reverse engineering, it is necessary to have not only metrological measurements and calculations using CAD, but also heuristic techniques that allow to recreate the conceptual model and design a new product instead of the damaged one taking into account real technological capabilities. These heuristic techniques are the selection of elements, the establishment of interrelations between elements, the identification of interrelated and independent groups of elements, the definition of inputs and outputs of the system, the use of models in the form of matrices and graphs. The relationship between realistic, conceptual, ideal and normative models is found in the case when the input data are the actual dimensions of the existing product, which are measured with certain errors. As a result of the work it is obtained the heuristic algorithm of the reverse engineering process for gear transmission; it is established that in order to determine the parameters of an ideal model, along with metrological measurements that allow us to find a realistic experimental model, it is necessary to use heuristic techniques and CAD; for complex engineering products with a high degree of standardization, reverse engineering is connected first of all with the use of databases of standard parts, elements of parts, steel grades, and the standard methods of calculation contained in CAE modules

Accurate coupled lines fitting in an errors-in-variables framework

For the purpose of accurate measurement of regular polygons, the boundary lines with parallel, perpendicular or given angles are defined as coupled lines. Provided that the noisy data points are measured from each line without outliers, an accurate and numerical reliable weighted total least squares (WTLS) method is proposed for two dimensional coupled lines fitting task. The underlying problem is modelled within an errors-in-variables framework by assuming all the coordinates are subject to random errors. In order to overcome the possible ill-posedness, the lines are parameterised as constrained Hessian normal form instead of the intercept and slope one. A generic WTLS algorithm is derived in case of the random columns are corrupted by fully correlated errors. Special case that the data are corrupted by homocedastic errors are considered and solved with less computational expenses. A single line fitting and a simulated regular hexagon fitting examples are performed with comparisons and discussions. The proposed methods can be used for accurate regular polygon measurement in vision metrology or reverse engineering.

Activity model for homogenization of data sets in laser-based powder bed fusion

PurposeAdditive manufacturing (AM) processes are the integration of many different science and engineering-related disciplines, such as material metrology, design, process planning, in-situ and off-line measurements and controls. Major integration challenges arise because of the increasing complexity of AM systems and a lack of support among vendors for interoperability. The result is that data cannot be readily shared among the components of that system. In an attempt to better homogenization this data, this paper aims to provide a reference model for data sharing of the activities to be under-taken in the AM process, laser-based powder bed fusion (PBF).Design/methodology/approachThe activity model identifies requirements for developing a process data model. The authors’ approach begins by formally decomposing the PBF processes using an activity-modeling methodology. The resulting activity model is a means to structure process-related PBF data and align that data with specific PBF sub-processes.FindingsThis model in this paper provides the means to understand the organization of process activities and sub-activities and the flows among them in AM PBF processes.Research limitations/implicationsThe model is for modeling AM activities and data associated with these activity. Data modeling is not included in this work.Social implicationsAfter modeling the selected PBF process and its sub-processes as activities, the authors discuss requirements for developing the development of more advanced process data models. Such models will provide a common terminology and new process knowledge that improve data management from various stages in AM.Originality/valueFundamental challenges in sharing/reusing data among heterogeneous systems include the lack of common data structures, vocabulary management systems and data interoperability methods. In this paper, the authors investigate these challenges specifically as they relate to process information for PBF – how it is captured, represented, stored and accessed. To do this, they focus on using methodical, information-modeling techniques in the context of design, process planning, fabrication, inspection and quality control.

Production quality controls and geometric characterization of the IFMIF-RFQ modules via the usage of a Coordinate Measuring Machine

The RFQ of the IFMIF/EVEDA project (Pérez et al., 2015) [1] is a 9.8m long cavity able to accelerate a 125mA deuteron beam from the input energy of 50 keV/u to the output energy of 2.5 MeV/u. Such RFQ operates at the frequency of 175MHz and is composed of 18 mechanical modules approximately 0.55 long each (Pepato et al., 2010) [2]. The RFQ realization involves the I.N.F.N. Sections of Padova, Torino and Bologna, as well as the Legnaro National Laboratories (L.N.L.). The metrological measurements via CMM (Coordinate Measuring Machine) provided to be a very effective tool both for quality controls along the RFQ production phases and in the reconstruction of the cavity geometric profile for each RFQ module. The scans in the most sensitive regions with respect to RF frequency, such as modulation, tips, base-vane width and vessel height provided the values of the cavity deviations from nominal geometry to be compared with design physic-driven tolerances and with RF measurements. Moreover, the comparison between mechanical and RF measurements suggests a methodology for the geometric reconstruction of the cavity axis and determines the final machining of the end surfaces of each module in view of the coupling with the adjacent ones. In this paper a detailed description of the metrological procedures and tests and of the RFQ along its production and assembly phases will be given and it will be shown that the adopted procedure allowed the attainment of the tuning range specifications for each RFQ module.

An equivalent source to describe realistic synchrotron hard X-rays

An equivalent source model was used to describe realistic third-generation synchrotron hard X-rays to avoid simplifying the light source model excessively or introducing too many variables from optical elements into quantitative calculation. By using particle swarm optimization, through secondary source with different slit apertures, the direct beam diffraction patterns on the detection plane propagated from the simulated equivalent source were in great agreement with the measured patterns. This study is hoped to reduce the difficulty of calculation and improve the accuracy of various coherent imaging or metrology measurements.

A metrological approach to improve accuracy and reliability of ammonia measurements in ambient air

The environmental impacts of ammonia (NH3) in ambient air have become more evident in the recent decades, leading to intensifying research in this field. A number of novel analytical techniques and monitoring instruments have been developed, and the quality and availability of reference gas mixtures used for the calibration of measuring instruments has also increased significantly. However, recent inter-comparison measurements show significant discrepancies, indicating that the majority of the newly developed devices and reference materials require further thorough validation. There is a clear need for more intensive metrological research focusing on quality assurance, intercomparability and validations. MetNH3 (Metrology for ammonia in ambient air) is a three-year project within the framework of the European Metrology Research Programme (EMRP), which aims to bring metrological traceability to ambient ammonia measurements in the 0.5–500 nmol mol−1 amount fraction range. This is addressed by working in three areas: (1) improving accuracy and stability of static and dynamic reference gas mixtures, (2) developing an optical transfer standard and (3) establishing the link between high-accuracy metrological standards and field measurements. In this article we describe the concept, aims and first results of the project.

The Influence of Motor Skills on Measurement Accuracy

Abstract This innovative study trying to do interdisciplinary interface at first view different ways fields: kinantropology and mechanical engineering. A motor skill is described as an action which involves the movement of muscles in a body. Gross motor skills permit functions as a running, jumping, walking, punching, lifting and throwing a ball, maintaining a body balance, coordinating etc. Fine motor skills captures smaller neuromuscular actions, such as holding an object between the thumb and a finger. In mechanical inspection, the accuracy of measurement is most important aspect. The accuracy of measurement to some extent is also dependent upon the sense of sight or sense of touch associated with fine motor skills. It is therefore clear that the level of motor skills will affect the precision and accuracy of measurement in metrology. Aim of this study is literature review to find out fine motor skills level of individuals and determine the potential effect of different fine motor skill performance on precision and accuracy of mechanical engineering measuring.

Experimental Study on 28nm Chip/Package Interactions in eWLB (Embedded Wafer Level BGA) Fan-Out Wafer Level Packages

To meet the continued demand for form factor reduction and functional integration of electronic devices, WLP (Wafer Level Packaging) is an attractive packaging solution with many advantages in comparison with standard BGA (Ball Grid Array) packages. The advancement of fan-out WLP has made it a more promising solution as compared with fan-in WLP, because it can offer greater flexibility in enabling more IO's, multi-chips, heterogeneous integration and 3D SiP. In particular, eWLB (Embedded Wafer Level BGA) is a fan-out WLP solution which can enable applications that require higher I/O density, smaller form factor, excellent heat dissipation, and thin package profile, and it has the potential to evolve in various configurations with proven integration flexibility, process robustness, manufacturing capacity and production yield. It also facilitates integration of multiple dies vertically and horizontally in a single package without using substrates. For eWLB fan-out WLP, the structural design as well as selection of materials is very important in determining the process yield and long term reliability. Therefore it is necessary to investigate the key design factors affecting the reliability comprehensively. This work is focused on an experimental study on the chip-package interactions in eWLB fan-out WLP with multilayer RDL's. Standard JEDEC component and board level tests were carried out to investigate reliability, and both destructive and non-destructive analyses were performed to investigate potential structural defects. Warpage, die cracking and other failures were characterized through metrology measurements and electrical tests. Board assembly processes (including SMT, underfill, etc.) were also studied. The influence of materials and structural design on the package reliability will be demonstrated. Thermal characterization and thermo-mechanical simulation results will also be discussed.

Cross-section the laser beam of the structure for measuring the distance and orientation of the robot manipulator

For stand-alone measure the distance of the robot manipulator or a robot as a whole and its orientation with respect to a reference surface is proposed to use optical-electronic system - standing with a camera and a laser module based on diode laser optics, forming a cross-shaped structure of the cross-section of the radiation beam . Opto- electronic system is mounted on the manipulator. At this point of intersection lines formed on a structured surface of an article by a laser beam in a cross can be used to measure distances and angular coordinates lines - for measuring the relative orientation of the manipulator of the measuring system. Measuring distances on the cross point, in fact, little different from the distance measurements on the position of the laser spot on the surface of the product in laser triangulation distance meter, the metrological parameters are studied in some detail, but in this case the particular topology of the cross-section of the laser beam widen the range of measurable distances . Metrological potential orientation measurements using intersecting lines on the surface of the base has not been studied, and that was the basis for this study.

Modeling of surface metrology of state-of-the-art x-ray mirrors as a result of stochastic polishing process

The design and evaluation of the expected performance of optical systems requires sophisticated and reliable information about the surface topography of planned optical elements before they are fabricated. The problem is especially severe in the case of x-ray optics for modern diffraction-limited-electron-ring and free-electron-laser x-ray facilities, as well as x-ray astrophysics missions, such as the X-ray Surveyor under development. Modern x-ray source facilities are reliant upon the availability of optics of unprecedented quality, with surface slope accuracy <0.1 μrad. The unprecedented high angular resolution and throughput of future x-ray space observatories require high-quality optics of 100 m2 in total area. The uniqueness of the optics and limited number of proficient vendors make the fabrication extremely time-consuming and expensive, mostly due to the limitations in accuracy and measurement rate of metrology used in fabrication. We continue investigating the possibility of improving metrology efficiency via comprehensive statistical treatment of a compact volume of metrology of surface topography, which is considered the result of a stochastic polishing process. We suggest, verify, and discuss an analytical algorithm for identification of an optimal symmetric time-invariant linear filter model with a minimum number of parameters and smallest residual error. If successful, the modeling could provide feedback to deterministic polishing processes, avoiding time-consuming, whole-scale metrology measurements over the entire optical surface with the resolution required to cover the entire desired spatial frequency range. The modeling also allows forecasting of metrology data for optics made by the same vendor and technology. The forecast data are vital for reliable specification for optical fabrication, evaluated from numerical simulation to be exactly adequate for the required system performance, avoiding both over- and underspecification.

APPLICATION OF VISION METROLOGY TO IN-ORBIT MEASUREMENT OF LARGE REFLECTOR ONBOARD COMMUNICATION SATELLITE FOR NEXT GENERATION MOBILE SATELLITE COMMUNICATION

Abstract. Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&amp;amp;D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1) Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order 2) Trial measurement for large structure with similar dimension with large deployable reflector to confirm the validity of the network design and instrumentation. In this report, the overview of this R&amp;amp;D project and the results of feasibility study of network design based on simulations on vision metrology and beam pattern compensation of antenna with very large reflector in orbit is discussed. The feasibility of assumed network design for vision metrology and satisfaction of accuracy requirements are discussed. The feasibility of beam pattern compensation by using accurately measured reflector shape is confirmed with antenna pattern simulation for deformed parabola reflector. If reflector surface of communication satellite can be measured routinely in orbit, the antenna pattern can be compensated and maintain the high performance every moment.

Cooperative data fusion of transmission and surface scan for improving limited-angle computed tomography reconstruction

Limited-angle computed tomography allows faster inspection during production, but the reconstruction from limited-angle transmission data is an underdetermined problem which cannot be solved without any prior knowledge of the sample. In this paper, surface data from an optical scan is selected as prior information due to its high accuracy and availability. To incorporate this information, we have developed a new cooperative data fusion model in the compressed sensing framework. The model has been applied to numerical and experimental data and solved with a tailored algorithm. We demonstrate the benefit of the data fusion model and prove the robustness of the algorithm. The results from this study indicate that the data fusion process combines features resolved by both modalities and gives a significant increase in image quality. These improvements enable metrological measurements that are impossible with data acquired with any single modality.

Designing A Digital Multimedia Interactive Book for Industrial Metrology Measurement Learning

This research aims to develop a digital multimedia interactive book for supporting the learning of industrial metrology and to examine the worthiness/value of the produced digital multimedia interactive book. It employs the approach of research and development. The design of the digital multimedia interactive book is implemented in some development stages: (1) material data collection, (2) planning, (3) making a prototype, (4) pilot test with respondents of multimedia experts and experts of industrial metrology, (5) improvement of the prototype, (6) application to students, (7) improvement of the final product. The final product of this research is a software multimedia digital interactive book which can be used to help students learn industrial metrology measurement. With this software, students can learn about industrial metrology whenever and wherever they are. Therefore, it can improve their competency, especially in the measurement.

Low cost digital close range photogrammetric measurement of an as-built anchor handling tug hull

A close range photogrammetric (CRP) model of an as-built 40m anchor handling tug hull located in an open space shipyard was constructed in this study through the use of a low cost amateur digital single-lens reflex camera, together with a modestly priced photogrammetric software. Through a series of comprehensive statistical tests, the constructed CRP tug hull model was quantitatively evaluated and analyzed by comparing the CRP measurements with the manually measured tug hull offset data from a lines-plan drawing. The statistical tests showed that most of the measured target coordinates were considerably accurate in this study, with absolute mean of error 4.1mm and absolute standard deviation of error ±4.5mm. Paired Student t-test showed that the modeled CRP Z-offset data (ZCRP) is not statistically different from the actual Z-offset data, ZOFF (p>0.05). Linear regression analysis also illustrates a near perfect linear relationship between these two variables. The accuracy achieved in this study is considerably good and sufficient for usual metrological measurement in small- or medium-sized shipbuilding industry, despites the presence of disturbances related to the characteristics of the open space shipyard. In future, a better targeting approach or target material should be used to further improve the CRP measurement accuracy.

Development of a multi-lane X-ray mirror providing variable beam sizes.

Grazing incidence mirrors are used on most X-ray synchrotron beamlines to focus, collimate or suppress harmonics. Increasingly beamline users are demanding variable beam shapes and sizes at the sample position. We have now developed a new concept to rapidly vary the beam size and shape of a focused X-ray beam. The surface of an elliptically figured mirror is divided into a number of laterally separated lanes, each of which is given an additional longitudinal height profile calculated to shape the X-ray beam to a top-hat profile in the focal plane. We have now fabricated two prototype mirrors and present the results of metrology tests and measurements made with one of the mirrors focusing the X-rays on a synchrotron beamline. We envisage that such mirrors could be widely applied to rapid beam-size switching on many synchrotron beamlines.