Journal articles: 'Optical measuring machines'

1

Caja, Jesús, Emilio Gómez, Piera Maresca, and Miguel Berzal. "Uncertainty Estimation for the Optical System of Optical Measuring Machines." Key Engineering Materials 615 (June 2014): 95–101. http://dx.doi.org/10.4028/www.scientific.net/kem.615.95.

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This paper presents the problem of optical measuring machine calibration, emphasizing the calibration of the "optical system", omitting the calibration of the "machine system". The calibration of an optical measuring machine is the first step before using the instrument for any application. For this purpose, a mathematical model has been developed to transform the coordinates of a point in space (3D) into coordinates of a point in an image (2D). Using this camera model, a calibration procedure has been developed using a grid distortion pattern. Finally, a procedure for calculating the uncertainty of the camera and geometric distortion parameters based on the Monte Carlo method has been developed.

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Caja, J., E. Gómez, P. Maresca, and M. Berzal. "Development of a Calibration Model for Optical Measuring Machines." Procedia Engineering 63 (2013): 225–33. http://dx.doi.org/10.1016/j.proeng.2013.08.187.

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Harmatys, Wiktor, Michael Marxer, Piotr Gąska, Maciej Gruza, and Adam Gąska. "The modelling of the measuring point reproduction error for optical coordinate measuring machines." MATEC Web of Conferences 322 (2020): 01053. http://dx.doi.org/10.1051/matecconf/202032201053.

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Coordinate measuring machines (CMMs) are the most common measuring systems used for assessing the compliance of manufactured components with their geometrical specifications. Optical CMMs are currently gaining popularity as they enable fast and contactless measurement with accuracy almost as high as in case of tactile measurement. During the performing of measurement, the points at which the measurement is conducted are usually not exactly at the intended location, but due to different impacts (error sources), they are in the area surrounding this location. This paper presents a method for modelling the reproduction of point coordinates as probability ellipses geometrically limiting the area in which the actual measurement points may lie. Different mathematical algorithms for the description of these ellipses were examined and a discussion on the selection of the best method is presented in this paper.

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Mikš, Antonin, and Jiri Novak. "Noncontact interferometric optical probe for calibration of coordinate measuring machines." Applied Optics 50, no. 5 (February 4, 2011): 671. http://dx.doi.org/10.1364/ao.50.000671.

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Carmignato, S., A. Voltan, and E. Savio. "Metrological performance of optical coordinate measuring machines under industrial conditions." CIRP Annals 59, no. 1 (2010): 497–500. http://dx.doi.org/10.1016/j.cirp.2010.03.128.

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Christoph, R., and I. Schmidt. "Micro and nano coordinate measuring technology with optical and tactile optical probes in high precision coordinate measuring machines." International Journal of Nanomanufacturing 8, no. 5/6 (2012): 441. http://dx.doi.org/10.1504/ijnm.2012.051104.

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Chen, Jenn Yih, Wen Yang Chang, Bean Yin Lee, and Chi Shiun Lin. "Optical Image Inspection of Cutting Tool Geometry for Grinding Machines." Advanced Materials Research 579 (October 2012): 235–42. http://dx.doi.org/10.4028/www.scientific.net/amr.579.235.

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The purpose of this paper is to develop a tool image inspection and measuring system by C++ Builder. Firstly, tool images are captured online for geometry analysis via a disassembled inspection mechanism mounted on the Z-axis of a five-axis tool grinding machine. One can use the controller of the machine to set the coordinate location of the mechanism and implement the humanized functions of autofocusing and automatic measurements. The digital images are calculated by the subpixel approach to improve the measurement resolution, and filtered the edge point location by Hough transform to upgrade the precision. The human machine interface (HMI) has a tutoring manner for users to operate the measuring procedures. These proposed functions can measure the geometric dimension such as the diameter, radius, and angle of different end mills or drills after finishing the tool grinding processes. Furthermore, the grinding processes can refer the online measured results to compensate the tool dimension. Therefore, this online image inspection and measuring system can improve the precision of tool grinding, product quality, and reduce the product cost. Finally, experiments are presented to show that the repeatability errors are ± 2 μm and ± 1 μm for the diameter and the radius measurements of end mills, respectively. The percentage error is 0.116％ for measuring the point angle of a drill. Thus, the results demonstrate the effectiveness of the proposed method that can be employed to measure tool geometry of different cutting tools.

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Hansen, H. N., and L. De Chiffre. "A Combined Optical and Mechanical Reference Artefact for Coordinate Measuring Machines." CIRP Annals 46, no. 1 (1997): 467–70. http://dx.doi.org/10.1016/s0007-8506(07)60867-1.

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Jäger, Gerd, T. Hausotte, Eberhard Manske, H. J. Büchner, R. Mastylo, N. Dorozhovets, R. Füßl, and R. Grünwald. "Nanometrology – Nanopositioning- and Nanomeasuring Machine with Integrated Nanopobes." Materials Science Forum 505-507 (January 2006): 7–12. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.7.

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The paper describes the operation of a high-precision wide scale three-dimensional nanopositioning and nanomeasuring machine (NPM-Machine) having a resolution of 0,1 nm over the positioning and measuring range of 25 mm x 25 mm x 5 mm. The NPM-Machine has been developed by the Technische Universität Ilmenau and manufactured by the SIOS Meßtechnik GmbH Ilmenau. The machines are operating successfully in several German and foreign research institutes including the Physikalisch-Technische Bundesanstalt (PTB). The integration of several, optical and tactile probe systems and scanning force microscopes makes the NPM-Machine suitable for various tasks, such as large-area scanning probe microscopy, mask and water inspection, circuit testing as well as measuring optical and mechanical precision work pieces such as micro lens arrays, concave lenses, mm-step height standards.

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Kirkland, Eric, Thomas R. Kurfess, and Steven Y. Liang. "An Optical Coordinate Measuring Machine for Nanoscale Dimensional Metrology." Journal of Advanced Computational Intelligence and Intelligent Informatics 8, no. 1 (January 20, 2004): 39–44. http://dx.doi.org/10.20965/jaciii.2004.p0039.

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Coordinate Measuring Machines (CMMs) are commonly used for geometry verification and replication on solid parts and work pieces on many scales. As the parts predicable continues to grow smaller and smaller, so grows the need to accurately measure the dimensional accuracy of these parts. This is partly because of how the critical part tolerances become as dimensions shrink and geometries become more complex. Research is currently underway at the Georgia Institute of Technology to develop a system for dimensional metrology at the nano-scale. The goal is to develop a versatile, non-contact, three-dimensional system capable of making accurate measurements on the nano level of form attributes of micro electro-mechanically manufactured parts. The Nano-CMM developed consists of a laser probe, a 6-axis positioning table, and a support frame. This paper describes the calibration of probe, processing of measurement signals, detection of solid edges, and software interface for system automation.

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Maresca, P., J. Caja, V. Martínez, E. Gómez, and C. Barajas. "Considerations to the verification of optical measuring machines according to ISO 10360." Procedia Manufacturing 13 (2017): 511–18. http://dx.doi.org/10.1016/j.promfg.2017.09.075.

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Krawczyk, M., K. Kobiela, M. Jedynak, W. Harmatys, and J. Sładek. "Application of multi-position method to calibration using optical coordinate measuring machines." Measurement: Sensors 18 (December 2021): 100299. http://dx.doi.org/10.1016/j.measen.2021.100299.

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Neuschaefer-Rube, Ulrich, Michael Neugebauer, W. Ehrig, Markus Bartscher, and U. Hilpert. "Tactile and Optical Microsensors - Test Procedures and Standards." Key Engineering Materials 381-382 (June 2008): 23–26. http://dx.doi.org/10.4028/www.scientific.net/kem.381-382.23.

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This paper presents procedures and standards to test tactile and optical microsensors and micro-computed tomography (CT) systems. The tests are similar to the established tests for classical coordinate measuring machines and assess local and global sensor characteristics. For this purpose, adequate and miniaturized reference standards were manufactured, calibrated and tested. In addition, task-specific reference standards have been realized to determine special sensor characteristics such as the maximum slope angle measurable by optical sensors or specific errors of tactile-optical microprobes measuring deep microholes.

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14

Irwin, M. J. "Optical surveys of the Magellanic Bridge, Stream and outer halos." Symposium - International Astronomical Union 148 (1991): 453–62. http://dx.doi.org/10.1017/s0074180900201150.

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The HI envelope of the Magellanic System extends well beyond the obvious visible regions of each of the Clouds. Modern optical surveys based on UK Schmidt telescope plates and fast measuring machines are now starting to reveal the complex optical counterparts of some of these HI features.

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Acko, Bojan, Michael McCarthy, Frank Haertig, and Borut Buchmeister. "Standards for testing freeform measurement capability of optical and tactile coordinate measuring machines." Measurement Science and Technology 23, no. 9 (July 25, 2012): 094013. http://dx.doi.org/10.1088/0957-0233/23/9/094013.

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LIN Hu, 林虎, Frank Hrtig Frank Hrtig, Karin Kniel Karin Kniel, and 石照耀 SHI Zhao-yao. "Measurement of large gears by using portable coordinate measuring machines." Optics and Precision Engineering 21, no. 7 (2013): 1763–70. http://dx.doi.org/10.3788/ope.20132107.1763.

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Munro, R. G., and P. H. K. Ling. "A New Method of Measuring Involute Profile Deviations of Gear Teeth." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 210, no. 1 (January 1996): 63–67. http://dx.doi.org/10.1243/pime_proc_1996_210_170_02.

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The principle behind all involute profile measuring machines is to arrange for relative movements between the gear and a stylus, so that the stylus measures only the deviations from a perfect involute curve. Over the years a number of different ways have been devised to produce the relative movements, involving discs and levers, and more recently computer numerical controls (CNC). This paper draws attention to the fact that accurate, large displacement optical gratings remove the need for accurate motion generation by using software compensation. The principle is applied to a base disc type of machine, which can be easily converted so that its full diameter range can be covered by a handful of nominal size discs, rather than needing an accurate and unique size of disc for every gear base diameter. In addition the output display can be made similar to that of a modern CNC machine.

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Miroshnichenko, Igor P., Ivan A. Parinov, Shun-Hsyung Chang, and Chin-Feng Lin. "Features and Functionality of the Optical Interference Meter for Measurement of Surface Displacements of Control Objects." Coatings 11, no. 8 (August 19, 2021): 989. http://dx.doi.org/10.3390/coatings11080989.

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This article presents in detail the methodology and results of test studies of the functionality of a prospective optical setup for measuring the surface linear displacements of control objects, developed on the basis of a new interference measurement method, namely the “luminous point” method. The dependencies of the changes in intensity of the optical field of interference patterns are obtained, characterizing the features of the functional capabilities of the setup. It is experimentally confirmed that with significant changes in the angle of incidence of radiation on the surface of the control object, the sensitivity of the investigated setup does not change. The noted research results are most appropriate for use in the development of new contactless optical setups for measuring the displacements of the surfaces of control objects, and for use in various experimental works in the processes of the creation and production of machines and equipment, as well as in the diagnosis of the state of structural materials and power elements of machines and equipment during operation.

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Bulgaru, Marius, Vlad Bocăneț, and Mircea Muntean. "Research regarding tactile scanning versus optical scanning." MATEC Web of Conferences 299 (2019): 04013. http://dx.doi.org/10.1051/matecconf/201929904013.

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In today’s fast-moving world, the manufacturing industry must keep up with evolving trends. One such trend that has greatly impacted the manufacturing industry is called Industry 4.0 and is regarded as the fourth industrial revolution. In this revolution one important aspect is that of quality. This paper makes a comparative study between tactile and optical measuring machines in the context of Industry 4.0. As the manufacturing industry must be more flexible and solve problems in a timelier manner, it is important to identify the right technologies appropriate for quality control.

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Bahrawi, M., N. Farid, and M. Abdel-Hady. "Speckle Cross-Correlation Method in Measuring Fine Surface Displacements." Journal of Atomic, Molecular, and Optical Physics 2012 (December 5, 2012): 1–6. http://dx.doi.org/10.1155/2012/976376.

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Industrial applications need regular testing for the lifetime, movement, strength, and performance of manufacturing machines during production process. Since speckle photography is a simple economic technique, it is used in investigating object response under mechanical and thermal effects depending on the movement of the speckle patterns with respect to the deformation strength and direction. In the present work, the cross-correlation technique is used to analyze the speckle patterns by iterative method to define both values and directions of rigid body translation and expansion. In order to check the accuracy of the cross-correlation technique, the results are compared with the displacement values given by analyzing the Young's interference fringes resulted from the Fourier transformation of the speckle patterns. This noncontact technique is found to be accurate and informative depending on the stability and sensitivity of the optical system. This method of measurement is an effective tool in studying the hard cases of objects and machines under various effects.

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Maresca, P., E. Gómez, J. Caja, C. Barajas, and M. Berzal. "Use of coordinate measuring machines and digital optical machines for the geometric characterization of circumference arcs using the minimum zone method." Measurement 43, no. 6 (July 2010): 822–36. http://dx.doi.org/10.1016/j.measurement.2010.02.010.

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WEN Xiu-lan, 温秀兰, 王东霞 WANG Dong-xia, 朱晓春 ZHU Xiao-chun, and 赵艺兵 ZHAO Yi-bing. "Sampling strategy for free-form surface inspection by using coordinate measuring machines." Optics and Precision Engineering 22, no. 10 (2014): 2725–32. http://dx.doi.org/10.3788/ope.20142210.2725.

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Galanulis, Konstantin, Stephanie Adolf, and Harald Friebe. "Optical 3D Metrology for Optimization of Sheet Metal Forming Processes." Key Engineering Materials 639 (March 2015): 3–11. http://dx.doi.org/10.4028/www.scientific.net/kem.639.3.

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3D optical metrology methods are increasingly used in the research of sheet metal materials and in sheet metal production processes. Optical measuring systems are implemented in different process stages, including design, sheet metal material research and component development, tool making and production as well as series accompanying quality control.Today’s development processes are initially driven from computational methods. Especially for the development of sheet metal components the numerical forming simulation is an important tool. However, performing a reliable forming simulation requires accurate input parameters like 3D geometry data for meshing, material parameters and boundary conditions which can be obtained with optical measuring systems. Further on the validation of these numerical simulations is supported with optical full-field sheet metal forming analysis.In the tool manufacturing phase 3D measurement data contributes in reducing the time frame for CNC machining processes, for the try-out phase, future tool reproduction as well as for repair and maintenance.With automated 3D measuring solutions series accompanying quality control is performed to determine tool wear and to shorten the response time if problems in the production occur.This paper is extending past work [1] and discusses today’s contribution of optical 3D measuring techniques in sheet metal component development and production, covering the areas of determining input parameters for sheet metal forming simulations and its validation, tool manufacturing, including the try-out, and production quality control using automated optical measurement machines.

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Ali, Salah H. R. "Advanced Nanomeasuring Techniques for Surface Characterization." ISRN Optics 2012 (December 3, 2012): 1–23. http://dx.doi.org/10.5402/2012/859353.

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Advanced precise and accurate nanomeasurement techniques play an important role to improve the function and quality of surface characterization. There are two basic approaches, the hard measuring techniques and the soft computing measuring techniques. The advanced soft measuring techniques include coordinate measuring machines, roundness testing facilities, surface roughness, interferometric methods, confocal optical microscopy, scanning probe microscopy, and computed tomography at the level of nanometer scale. On the other hand, a new technical committee in ISO is established to address characterization issues posed by the areal surface texture and measurement methods. This paper reviews the major advanced soft metrology techniques obtained by optical, tactile, and other means using instruments, classification schemes of them, and their applications in the engineering surfaces. Furthermore, future trends under development in this area are presented and discussed to display proposed solutions for the important issues that need to be addressed scientifically.

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Takamasu, Kiyoshi, and Wiroj Sudatham. "High-Accuracy Absolute Length Measurement Using an Optical-Comb Pulsed Interferometer: Verification of Coordinate Measuring Machines." International Journal of Automation Technology 11, no. 5 (August 30, 2017): 682–90. http://dx.doi.org/10.20965/ijat.2017.p0682.

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The optical frequency comb has become a standard for length and frequency measurements. Its pulsed laser can produce temporal coherence interference fringe patterns, and these fringes can be used as the length standard for practical measurement of absolute lengths. This research aims to develop a measuring system for coordinate measuring machine (CMM) verification, which can be used to measure the absolute length of a target in three dimensions. Thus, a spherical target has been considered. A ball lens with a refractive index of 2.0 has been selected as the target for the interferometer in this study. Using the ball lens target, the absolute length can be measured up to 10 m, covering the medium- to large-sized range of CMM applications. The experimental results demonstrate that the measurement uncertainty is smaller than that of the artifact test. In addition, the measurement time of the proposed method is 60% less than that of the artifact-test method.

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Li, Rui-Jun, Kuang-Chao Fan, Jin-Wei Miao, Qiang-Xian Huang, Sheng Tao, and Er-min Gong. "An analogue contact probe using a compact 3D optical sensor for micro/nano coordinate measuring machines." Measurement Science and Technology 25, no. 9 (August 12, 2014): 094008. http://dx.doi.org/10.1088/0957-0233/25/9/094008.

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Zhang, Min, Bart Boeckmans, Jean Pierre Kruth, Wim Dewulf, and Zhao Yao Shi. "Metrology Performance of Laser Line Scanning of Additive Manufacturing Fixtures Based on Geometrical Product Specification (GPS)." Applied Mechanics and Materials 870 (September 2017): 153–58. http://dx.doi.org/10.4028/www.scientific.net/amm.870.153.

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To gain a maximum benefit of high-speed optical scanning in the metrological calibration of emerging AM (Additive Manufacturing) fixtures it is necessary to investigate the metrology performance of laser line scanning in particular on coordinate measuring machines (CMMs) based on new generation of Geometrical Product Specification standard. A set of designed experiments was set up both on an actual fixture and artefacts manufactured by the Additive Manufacturing company, Materialise-RapidFit+. It enables to identify the influence of a fixture’s geometrical characteristic, material, colour, transparency and roughness, as well as of the alignment of the part coordinate system (PCS) mathematically relating to the machine coordinate system (MCS). Performance measures that were tracked included inspection accuracy, measuring repeatability and time consumption. Results demonstrate that the laser line scanning strategy enables to lower the time consumption in the order of 49% for a fixture with six locators mounted on it and a PC with 128GB RAM, especially providing a superior accuracy performance for complex geometries compared to a tactile measuring strategy.

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Li, Rui-Jun, Ying-Jun Lei, Zhen-Xin Chang, Lian-Sheng Zhang, and Kuang-Chao Fan. "Development of a High-Sensitivity Optical Accelerometer for Low-Frequency Vibration Measurement." Sensors 18, no. 9 (September 1, 2018): 2910. http://dx.doi.org/10.3390/s18092910.

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Low-frequency vibration is a harmful factor that affects the accuracy of micro/nano-measuring machines. Low-frequency vibration cannot be completely eliminated by passive control methods, such as the use of air-floating platforms. Therefore, low-frequency vibrations must be measured before being actively suppressed. In this study, the design of a low-cost high-sensitivity optical accelerometer is proposed. This optical accelerometer mainly comprises three components: a seismic mass, a leaf spring, and a sensing component based on a four-quadrant photodetector (QPD). When a vibration is detected, the seismic mass moves up and down due to the effect of inertia, and the leaf spring exhibits a corresponding elastic deformation, which is amplified by using an optical lever and measured by the QPD. Then, the acceleration can be calculated. The resonant frequencies and elastic coefficients of various seismic structures are simulated to attain the optimal detection of low-frequency, low-amplitude vibration. The accelerometer is calibrated using a homemade vibration calibration system, and the calibration experimental results demonstrate that the sensitivity of the optical accelerometer is 1.74 V (m·s−2)−1, the measurement range of the accelerometer is 0.003–7.29 m·s−2, and the operating frequencies range of 0.4–12 Hz. The standard deviation from ten measurements is under 7.9 × 10−4 m·s−2. The efficacy of the optical accelerometer in measuring low-frequency, low-amplitude dynamic responses is verified.

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Hiyoshi, Noritake, Takamoto Itoh, Masao Sakane, Takafumi Tsurui, and Masaaki Tsurui. "Development of Multiaxial Creep Testing Machine for Miniature Specimen." MATEC Web of Conferences 300 (2019): 14001. http://dx.doi.org/10.1051/matecconf/201930014001.

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High temperature components such as boiler tube and jet engine turbine blade undergo multiaxial creep damage. Although multiaxial creep testing investigation is required for safety high temperature components designing, there are few commercial testing machines which can conduct multiaxial loading at high temperature. A new miniature cruciform specimen, which has a 5 mm square size plane stress gauge part, was designed by using FE analysis. A biaxial tensile loading creep testing machine was also designed to conduct multiaxial creep testing. The testing machine has 2 kN loading capacity and 1 kW furnace. We had also developed a non-contact displacement measuring method for the miniature specimen. This method uses conventional optical camera to get the surface observation photograph. Chasing the trace of the target mark painted at surface of the specimen, we can get the displacement of the specimen. The calculated strain value obtained from the non-contact displacement measuring method corresponds with the strain gauge value at room temperature. By using the multiaxial creep testing machine and the non-contact observation system, we can investigate not only deformation of the testing specimen but also surface conditions of materials during the creep testing.

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De Pauw, Ben, Francis Berghmans, Hugo Thienpont, Piet Verdiere, and Thomas Geernaert. "Optical fiber-based sensors as an experimental tool to assess the weft and warp yarn tension beam-to-roll in rapier weaving machines." Textile Research Journal 90, no. 7-8 (October 23, 2019): 857–65. http://dx.doi.org/10.1177/0040517519881817.

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High cycle rates are important in commercial weaving machines to maximize productivity. Faster operation, however, can lead to higher tension on the yarns, which in turn increases the occurrence of yarn breakage and thus machine interruptions. Significant work has therefore been conducted to improve the many weaving machine components with the goal to attain higher production rates without increasing the yarn loads. Quantifying the impact of such improvements is not always possible using conventional, indirect measurement techniques. In addition, these techniques are limited to locations with sufficient access to the yarn to mount a sensor, typically between the warp beam and the first harness. In this paper, we show that the use of optical fiber-based sensors allows directly measuring the yarn tension in both the warp and weft directions in the region from the warp beam to the fabric rolls in rapier-type weaving machines. To do so, we replaced one warp and one weft yarn with an optical fiber equipped with strain sensors and measured strain throughout the subsequent weaving process. The small diameter of the optical fiber allowed minimizing our intrusion on the weaving operation. Our main observations are four-fold. Firstly, we demonstrated how the strain on the warp yarns evolves during the weaving cycle and we used this to focus on the beat-up phase for a low weaving resistance situation. Secondly, we monitored the warp yarn tension between the warp beam and the fabric rolls. Thirdly, we exploited the multiplexing capability of the optical fiber sensors to obtain a tension distribution along the width of the fabric in the weft direction between the reed to the fabric roll. Fourthly, we observed and identified the different phases of a yarn insertion (weft-wise) in a double rigid rapier machine.

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Juraszek, Janusz. "Application of fiber optic FBG techniques in analysis of strain in engineering machines." New Trends in Production Engineering 2, no. 1 (October 1, 2019): 480–85. http://dx.doi.org/10.2478/ntpe-2019-0051.

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Abstract The paper presents the use of fiber optic FBG strain sensors for analysis of deformations of machines and devices including those used in mining techniques. FBG strain sensors have many advantages over classic strain measurements using electro resistance strain gauges. They are characterized by a significant measurement accuracy of up to 1 mm, a service life of up to 30 years, the possibility of measuring large deformations of up to 8%, significant fatigue life, the possibility of building measurement networks and, something extremely important in mining – intrinsic safety, because the operating medium is white light. The entire measurement system based on the optical interrogator was also discussed. It enables conducting both static and dynamic measurements. The results of the strain research for an engineering machine, in which the loads had exceeded 800 T, were reported.

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Krawiec, Piotr, Grzegorz Domek, Łukasz Warguła, Konrad Waluś, and Jarosław Adamiec. "The application of the optical system ATOS II for rapid prototyping methods of non-classical models of cogbelt pulleys." MATEC Web of Conferences 157 (2018): 01010. http://dx.doi.org/10.1051/matecconf/201815701010.

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The widespread application of both gear wheels and cogbelt pulleys with noncircular generating line in technique stimulates the development of manufacturing and measuring methods of these wheels. The paper presents the rapid prototyping methods of models of cogbelt pulleys with nocircular evelope. Evaluation method of manufacturing accuracy of cogbelt pulleys, which are applied in unevenrunning belt transmissions, are presented. These transmissions are widely applied in steering techniques and drives of machines and devices. Verification of mapping accuracy of shape of geometrical model of cogbelt pulley was done with the application of noncontact optical system i.e. coordinate optical scanner GOM Atos Compact Scan 5M GOM company.

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Cannon, R. D. "Lists of Active Galaxies, Problems of Detection and Statistics." Symposium - International Astronomical Union 121 (1987): 3–16. http://dx.doi.org/10.1017/s0074180900154841.

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The various techniques for discovering active galaxies are reviewed, the main emphasis being on optical techniques and their application to emission-line galaxies with active nuclei. The three principal sets of selection criteria involve morphology, colours and emission lines. The major extant lists of emission line galaxies are summarized. Problems of detection are discussed, including selection effects and the use of automatic plate measuring machines. The difficulties of generating useful statistics on different classes of objects are highlighted, but no attempt is made in deriving new statistics or to summarize those in the literature.

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Remond, Didier, and Jarir Mahfoudh. "From Transmission Error Measurements to Angular Sampling in Rotating Machines with Discrete Geometry." Shock and Vibration 12, no. 2 (2005): 149–61. http://dx.doi.org/10.1155/2005/205291.

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The benefits of angular sampling when measuring various signals in rotating machines are presented and discussed herein. The results are extracted from studies on transmission error measurements with optical encoders in the field of power transmissions and can be broadened to include phase difference measurements, such as torsional vibrations, and applied to control, monitoring and measurement in rotating machines with discrete geometry. The main conclusions are primarily that the use of angular sampling enables the exact location of harmonics and, consequently, the obtaining of spectral amplitude components with precision. This is always true even if the resolution of encoders is not directly related to the studied discrete geometry. It then becomes possible to compare these harmonics under different operating conditions, especially when speed varies, without changing any parameters in spectral analysis (window length, spectral resolution, etc.). Moreover, classical techniques of improving signal to noise ratio by averaging become fully efficient in the detection of defective elements. This study has been made possible thanks to the technique of transmission error measurement with optical encoders that allows the comparison of sampling procedures, based on the same raw data.The intensive use of such transducers and the development of an original transmission error measurement technique lead to advocate the use of angular sampling in experimental measurements in rotating machines with discrete geometry.

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Zimmermann, Dennis, Andreas Beutler, Matthias Brozio, Simon Freutel, Philipp Kosse, and Cornelius Neumann. "A procedure for designing and manufacturing microstructured lenses used in automotive headlamps." Advanced Optical Technologies 8, no. 6 (December 18, 2019): 483–89. http://dx.doi.org/10.1515/aot-2019-0031.

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Abstract The transition between the light and dark areas of the luminous intensity distribution of a headlamp needs to fulfil statutory regulations. For projection headlamps, adjusting the transition is done by adding a scattering structure to the lens surface. The requirements for the transition are pointed out, and typical problems are presented. A procedure to create such scattering structures in computer-aided design is shown. Improvements to the controls of turning machines for manufacturing are discussed. A reverse engineering process using a high-precision cylindrical coordinate measuring instrument with an optical probe for quality assurance is presented.

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Hinczewski, Michael, Changbong Hyeon, and D. Thirumalai. "Directly measuring single-molecule heterogeneity using force spectroscopy." Proceedings of the National Academy of Sciences 113, no. 27 (June 17, 2016): E3852—E3861. http://dx.doi.org/10.1073/pnas.1518389113.

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One of the most intriguing results of single-molecule experiments on proteins and nucleic acids is the discovery of functional heterogeneity: the observation that complex cellular machines exhibit multiple, biologically active conformations. The structural differences between these conformations may be subtle, but each distinct state can be remarkably long-lived, with interconversions between states occurring only at macroscopic timescales, fractions of a second or longer. Although we now have proof of functional heterogeneity in a handful of systems—enzymes, motors, adhesion complexes—identifying and measuring it remains a formidable challenge. Here, we show that evidence of this phenomenon is more widespread than previously known, encoded in data collected from some of the most well-established single-molecule techniques: atomic force microscopy or optical tweezer pulling experiments. We present a theoretical procedure for analyzing distributions of rupture/unfolding forces recorded at different pulling speeds. This results in a single parameter, quantifying the degree of heterogeneity, and also leads to bounds on the equilibration and conformational interconversion timescales. Surveying 10 published datasets, we find heterogeneity in 5 of them, all with interconversion rates slower than 10 s−1. Moreover, we identify two systems where additional data at realizable pulling velocities is likely to find a theoretically predicted, but so far unobserved crossover regime between heterogeneous and nonheterogeneous behavior. The significance of this regime is that it will allow far more precise estimates of the slow conformational switching times, one of the least understood aspects of functional heterogeneity.

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Ismagilov, Flur R., Viacheslav Evgenievich Vavilov, Denis Valerievich Gusakov, Aibulat Kh Miniyarov, and Valentina V. Ayguzina. "DIAGNOSTIC METHOD OF ROTOR CRACKS AND LOCAL DEMAGNETIZATION BY USING THE MEASURING COILS FOR THE PERMANENT MAGNET SYNCHRONOUS MACHINES." Progress In Electromagnetics Research C 86 (2018): 123–36. http://dx.doi.org/10.2528/pierc18070205.

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Kapłonek, Wojciech, Krzysztof Nadolny, Bartosz Zieliński, Jarosław Plichta, Danil Pimenov, and Shubham Sharma. "The Role of Observation–Measurement Methods in the Surface Characterization of X39Cr13 Stainless-Steel Cutting Blades Used in the Fish Processing Industry." Materials 13, no. 24 (December 18, 2020): 5796. http://dx.doi.org/10.3390/ma13245796.

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In the modern fish processing industry, flat fishes play an important role. They are processed into a final product in the form of a fillet during the skinning operation, which is carried out on machines operating in automated production lines. These machines are usually equipped with a single planar cutting blade or a few of such blades. The high-efficiency skinning and industrial conditions cause rapid wear of the cutting edge of the blade, which is detrimental to the quality of the final product. One of the forms of renewing the cutting ability of these types of tools is the regeneration carried out with the use of precise traverse surface grinding. The results of this process must be carefully verified for determining its correctness and possible optimization of its parameters. The main goal of this article was to characterize the usefulness of a number of observational and measuring methods to evaluate the results of the technical blade regeneration process. In this work, a number of contemporary observation–measurement methods such as optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), optical profilometry (OP), and angle-resolved scattering (ARS), supported by image processing and analysis techniques, were analyzed. The authors focused on presenting the role of the abovementioned methods in the surface characterization of planar cutting blades made of X39Cr13 chromium martensitic stainless steel before and after the technological operation of flat-fish skinning. Additionally, the surface condition after the regeneration process carried out using the five-axis CNC (computerized numerical control) grinding machine was also assessed. Numerous results of surface observations, elemental composition microanalysis, high-accuracy surface microgeometry measurements, and quantitative and qualitative analysis confirming the possibility of using the proposed methods in the presented applications are presented.

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Zhu, Ling Jian, Zong Ming Qiu, Qi Li, and Huai Jun Zhao. "A Design of Multifunctional Laser Aiming Probe." Advanced Materials Research 468-471 (February 2012): 156–60. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.156.

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A multifunctional laser aiming probe applied on coordinate measurement machines was designed and presented in this paper based on half facular point optical imagery. The designing thought and operation principle of the multifunctional aiming probe’s optical system was introduced and analyzed in detail. An adaptive intensity control method was used in the circuit to adjust the laser intensity timely so that it can adapt to aiming measurement of different optical properties surface. Repeated aiming trigger experiment was conducted and the experimental results showed that the measurement repetitive standard deviation of the multifunctional probe was better than 0.5μm without any other accessorial equipment, which can be satisfied with the use requirements of CMMs. This probe with the characteristics of high detecting speed, high degree of automation and high aiming accuracy, will be expected to have the ability of free curved surface and imagery tracking aiming measurement of contour with higher speed and accuracy coincided with CMMs or other length measurement instruments and have a wide range of application prospects and a strong practical value in measuring for parts profile with a higher precision.

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Voicu, Adrian Catalin, and Gheorghe I. Gheorghe. "Complex 3D Measuring by Multiple Laser Scanning of Automotive Parts." Advanced Materials Research 837 (November 2013): 511–16. http://dx.doi.org/10.4028/www.scientific.net/amr.837.511.

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For over 20 years the term"three-dimensional scan"(3D) showed the world the possibilities of virtual design, simulation, or reverse engineering. 3D scanning is also known as 3D digitizing, the name coming from the fact that this is a process that uses a contact or non-contact digitizing probe to capture the objects form and recreate them in a virtual workspace through a very dense network of points (xyz) as a 3D graph representation. Until recently, digitization was limited by the speed of the scan head and the correct choice of the probing system, type of scanned piece and budget for the purchase or develops the scanning system. With the evolution of technology appeared a number of new techniques that tend to improve the properties of classical methods. Even if intended for copying or geometrical control, or rather virtual geometric modelling or product realization, there are two groups of technologies: with contact (classical methods with probes) or without contact (laser, optical or combination). Most automotive manufacturers currently use 3D scan metrology based on optical or laser systems to validate products quality. The pieces are initially measured by 3D scanning then they are compared with the designed model (CAD file) using a specialized software. By this comparison producer can interfere very quickly in the manufacturing process to remove the cause of defects, this technique being called Reverse Engineering (RE). There are many variables that affect accuracy of laser scanning and therefore the quality of information: reflectance of surface, colour object, recesses, openings narrow and sharp edges can be difficult to scan. This accuracy may vary from micron to millimetre and the acquisitions size from a few points to several thousand points per second. The overall accuracy of a 3D acquisition system depends above all on the sensors precision and on the acquisition device (acquisition with contact) or acquisition structure (acquisition without contact). In a perfect world or in an integrated production environment, 3D measuring systems should be able to measure all the necessary parameters in a single step without errors, and to render the results in the same way to the manufacturing networks equipped with computers, in formats useful for machines control and processes management.

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ČAVLOVIĆ, ANKA OZANA, and IVAN BEŠLIĆ. "APPLICATION OF PHOTOMETRY IN DETERMINING THE DUST MASS CONCENTRATION OF HARDWOODS." WOOD RESEARCH 66(4) 2021 66, no. 4 (September 9, 2021): 678–88. http://dx.doi.org/10.37763/wr.1336-4561/66.4.678688.

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Given the carcinogenicity of hardwood dust, the aim of this study was to determine the effectiveness of the photometric method for different types of woodworking machines and its application in determining the mass concentration of inhalable dust for raw and dry hardwoods. In addition to the optical part of the device, the input part of the measuring device contains the Institute of Occupational Medicine (IOM) inhalable dust filter holder. This correlation of gravimetric and photometric methods in determining the dust mass concentration showed that photometry underestimates the mass concentration measured gravimetrically. The results of this study recommend the application of a correction factor 2 for a timber band saw and a correction factor 3 for circular saws in determining the mass concentration of hardwood dust by the photometric method. It was showed that photometry can be used if the correction factor of the optical device has been previously tested for specific wood processing place.

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de Felice, Fabio, Antonella Petrillo, and Armando Carlomusto. "Shape Measurement Based on 3D Optical Scanner: Real Case Study in the Aeronautics Industry." Applied Mechanics and Materials 656 (October 2014): 378–87. http://dx.doi.org/10.4028/www.scientific.net/amm.656.378.

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Three dimensional (3-D) geometric shape measurements have found wide applications in the fields of industrial manufacturing, fast reverse engineering, quality control, biomedical sciences, etc. In the present paper we focus our attention on Reverse engineering. It starts from an existing product, and creates a CAD (Computer Aided Design) model, for modification or reproduction of its design. This kind of process is usually undertaken in order to redesign a system for better maintainability or to obtain a copy of a system without access to design from which it was originally produced. There are many different methods for acquiring shape data. Tactile methods represent a popular approach to shape capture. The most commonly known forms are Coordinate Measuring Machines (CMMs) and mechanical or robotic arms with a touch probe sensing device. Non-contact methods use light, sound or magnetic fields to acquire shape from objects. In the case of contact and non-contact, an appropriate analysis must be performed to determine the positions of points on objects surface. The aim of this paper is to present a new reconstruction method of three-dimensional measuring system for objects acquisition:reverse engineering based on structured light system. This technique consists in projecting a known pattern of pixels (structured light) on an object: the way in which this pattern is deformed encountering the object surfaces, allows vision systems (a couple of monochromatic digital cameras) to calculate depth information necessary for surfaces digitization. The subsequent application of this methodology has been to reengineer an aeronautical component that has changed over time and divergent from initial project. At last have been studied proposals and possible solutions that ensure an higher quality of manufactured products and a substantial savings in costs of production system of the product itself.

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Voicu, Adrian Catalin, Ion Gheorghe Gheorghe, Liliana Laura Badita, and Adriana Cirstoiu. "3D Measuring of Complex Automotive Parts by Multiple Laser Scanning." Applied Mechanics and Materials 371 (August 2013): 519–23. http://dx.doi.org/10.4028/www.scientific.net/amm.371.519.

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Three-dimensional scanning is available for more than 15 years, however there are few that have heard of it and as few people know the applications of this technology. 3D scanning is also known as 3D digitizing, the name coming from the fact that this is a process that uses a contact or non-contact digitizing probe to capture the objects form and recreate them in a virtual workspace through a very dense network of points (xyz) as a 3D graph representation. Based on this information have been developed many new applications in many fields - computer games industry, prosthetics or forensic medicine, the arts and culture area - but the most common area where scanning systems are used remains the automotive industry, aircraft and consumer goods. Most automotive manufacturers currently use 3D metrology based on optical or laser systems to validate products quality. The pieces are initially measured by 3D scanning then they are compared with the designed model (CAD file) using a specialized software. By this comparison producer can interfere very quickly in the manufacturing process to remove the cause of defects, this technique being called Reverse Engineering (RE). The overall accuracy of a 3D acquisition system depends above all on the sensors precision and on the acquisition device (acquisition with contact) or acquisition structure (acquisition without contact). This accuracy may vary from micron to millimeter and the acquisitions size from a few points to several thousand points per second. In a perfect world or in an integrated production environment, 3D measuring systems should be able to measure all the necessary parameters in a single step without errors, and to render the results in the same way to the manufacturing networks equipped with computers, in formats useful for machines control and processes management.

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Behrens, Bernd Arno, Richard Krimm, and Valerian Salfeld. "Process-Machine Interaction in Sheet-Bulk Metal Forming." Key Engineering Materials 504-506 (February 2012): 999–1004. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.999.

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The present contribution deals with the process-machine interaction and its impacts on the workpiece quality by forming parts with sheet-bulk metal forming. It focuses on the manufacturing of complex asymmetrical parts with functional elements. The functional applications of these elements such as fixation, motion and load transmission require compliance with high geometrical accuracy as well as high precision regarding the final mechanical properties of the part. The high process forces in horizontal as well as in vertical direction to form these elements cause displacements of the tool and press components, which lead to workpiece defects retroactively. Although the interaction between the forming machine and process affects the quality of the finished part significantly, the machine influence is usually ignored in the analysis of the forming process with the Finite-Element-Method. The challenges mentioned are demonstrated by forming of a complex asymmetrical part with gear teeths and carrier elements. As typical for sheet-bulk metal forming, the dimensions of the finished gear teeths (4mm) are much higher as the initial thickness of the sheet metal (3mm). The displacements of the press components during the process have been determined by means of optical measuring systems. The results are presented in all three spatial directions. The conclusions about the acting process forces in horizontal and vertical direction have been made by analyzing the press displacements by means of a new developed three-axial load device. Finally, this paper introduces a suitable approach to represent the machine characteristics in order to improve the computational accuracy of sheet-bulk metal forming simulations and gives an overview about the possibilities to improve the process stability by improving the mechanical components of forming machines.

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Anthymidis, K. G., A. Balouktsis, Kostas David, and A. Trakali. "Wear of Cutting Tools Used in Milling Treatments." Key Engineering Materials 465 (January 2011): 165–68. http://dx.doi.org/10.4028/www.scientific.net/kem.465.165.

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The usage of Computer Numerical Controlled Machines has been generalized over the last decades due to the increased demands for the production of mechanical parts with précised dimensions, higher production rates and products with better treated surface quality. It is well known that the duration of life of a cutting tool is one of the most important parameters during the cutting of metal parts, because it affects the cost of the manufacturing process substantially. Therefore, it is important to know accurately, the relation between the duration of life of the cutting tool and the conditions of the machinery such as cutting velocity, feed rate (fz), the depth of cut (radial and axial) etc. The purpose of this research is to conduct a proper number of cutting experiments in milling, measuring the wear of the cutting tools, in order to conclude in a mathematical model the wear cutting tool. This model can be implemented for the prediction of the cutting tool life, which is very important for the determination of the best cutting conditions. From the experimental diagrams we can come to conclusions for the course of the wear of the cutting tool in connection with the velocity of cutting, for the machinability of the materials used etc. The wear of the used cutting tools was determined by means of optical microscopy and stereoscopy.

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Casagrande, Maria, Robert Kromer, Daniel A. Wenzel, Sven Poli, Martin S. Spitzer, Vasyl Druchkiv, Maximilian Schultheiss, and Spyridon Dimopoulos. "Determination of Ischemia Onset Based on Automatically Generated Spectralis SD-OCT Values in Acute Central Retinal Artery Occlusion." Journal of Ophthalmology 2021 (April 14, 2021): 1–7. http://dx.doi.org/10.1155/2021/5527292.

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Acute central retinal artery occlusion (CRAO) induces a time-dependent increase in retinal thickness. By manually measuring the relative retinal thickness increase (RRTI) in comparison to the contralateral eye based on optical coherence tomography (OCT), ischemia onset within the past 4.5 hours could be determined with 100% sensitivity and 94.3% specificity. To enable examiner-independent and quicker diagnostics, we analyzed the RRTI using the automatic retinal thickness measurement. In this retrospective study, 28 eyes were evaluated with an acute CRAO (<46 hours). All patients received a Spectralis SD-OCT image of both eyes. The RRTI was calculated for the ETDRS sectors using the Segmentation Module for Single Retinal Layer Analysis. Receiver operating characteristic (ROC) analysis was performed to determine patients ≤4.5 hours by RRTI. In all sectors, time to OCT (TTO) and RRTI correlated positively. The optimal cutoff point to detect CRAOs ≤4.5 hours was between 18.7% nasally and 22.9% RRTI temporally. Sensitivity and specificity varied between the sectors with 90–95% sensitivity and 89–100% specificity. In conclusion, the automatic measurement of RRTI also allows the differentiation of CRAOs within a possible therapeutic time window ≤4.5 hours and CRAOs ≥4.5 hours with a high sensitivity and specificity. Additionally, it offers quicker, easier, and a user-independent assessment of ischemia onset, helping to set a base for establishing automatic indices generated by the OCT machines.

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Hecht, J., K. Lamprecht, Marion Merklein, Konstantin Galanulis, and J. Steinbeck. "Triangulation Based Digitizing of Tooling and Sheet Metal Part Surfaces - Measuring Technique, Analysis of Deviation to CAD and Remarks on Use of 3D-Coordinate Fields for the Finite Element Analysis." Key Engineering Materials 344 (July 2007): 847–53. http://dx.doi.org/10.4028/www.scientific.net/kem.344.847.

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The dynamic development of highly accurate optical measuring machines within the last years pushed the introduction of digitizing techniques to many applications in the fields of quality control, reverse engineering and rapid prototyping. By projecting fringe patterns onto the object's surface and recording pictures of the curvature dependant deformation of the pattern, 3D coordinates for each camera pixel are calculated on the basis of the principle of triangulation. The generation of a polygon mesh can be used for the analysis of the deviation of a die or a formed part to the initial CAD data, i.e. by means of full field or section based comparison. This paper presents the application of the above mentioned techniques on a double sheet hydroforming process. The gathered 3D data of the clam-shell part as well as of the tooling dies served for the calculation of the deviation to the respective reference geometry. With respect to the utilization of digitized tooling data within the finite element analysis, further investigations were performed on the impact of data reduction strategies. Aiming on the minimization of the necessary number of elements, representing the tooling surface in a discrete state, and on the request for a sufficient degree of accuracy, these strategies have to be considered of high priority.

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Uhlmann, Eckart, Gerhard Häusler, Christian Röttinger, Evelyn Olesch, Christian Faber, and M. Kurz. "Machine Integrated Measurement of Ultra Precision Machined Specular Non-Rotational Symmetrical Surfaces." Advanced Materials Research 907 (April 2014): 277–89. http://dx.doi.org/10.4028/www.scientific.net/amr.907.277.

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In this paper, current results of a research project combining ultra precision machining and optical measurement are presented. The goal is to improve the quality of specular freeform surfaces manufactured by ultra precision slow slide servo turning by running appropriate correction cycles on the basis of machine integrated measurements. These measurements are conducted using the principle of Phase Measuring Deflectometry (PMD) in order to optically acquire full-field 3D-height data. For this purpose, a special setup the so called Mini PMD that can be operated within the limited installation space of an ultra precision machine tool has been designed and implemented. Results of machine integrated measurements of a specular non-rotational symmetrical surface are presented. Furthermore, using Mini PMD and a rotationally symmetric test surface, a complete correction cycle is demonstrated without the necessity of taking the workpiece off the machine for measurement.

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Neri, Paolo, Alessandro Paoli, and Ciro Santus. "Stereo-DIC Measurements of a Vibrating Bladed Disk: In-Depth Analysis of Full-Field Deformed Shapes." Applied Sciences 11, no. 12 (June 11, 2021): 5430. http://dx.doi.org/10.3390/app11125430.

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Vibration measurements of turbomachinery components are of utmost importance to characterize the dynamic behavior of rotating machines, thus preventing undesired operating conditions. Local techniques such as strain gauges or laser Doppler vibrometers are usually adopted to collect vibration data. However, these approaches provide single-point and generally 1D measurements. The present work proposes an optical technique, which uses two low-speed cameras, a multimedia projector, and three-dimensional digital image correlation (3D-DIC) to provide full-field measurements of a bladed disk undergoing harmonic response analysis (i.e., pure sinusoidal excitation) in the kHz range. The proposed approach exploits a downsampling strategy to overcome the limitations introduced by low-speed cameras. The developed experimental setup was used to measure the response of a bladed disk subjected to an excitation frequency above 6 kHz, providing a deep insight in the deformed shapes, in terms of amplitude and phase distributions, which could not be feasible with single-point sensors. Results demonstrated the system’s effectiveness in measuring amplitudes of few microns, also evidencing blade mistuning effects. A deeper insight into the deformed shape analysis was provided by considering the phase maps on the entire blisk geometry, and phase variation lines were observed on the blades for high excitation frequency.

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Kerrouche, Abdelfateh, Taoufik Najeh, and Pablo Jaen-Sola. "Experimental Strain Measurement Approach Using Fiber Bragg Grating Sensors for Monitoring of Railway Switches and Crossings." Sensors 21, no. 11 (May 24, 2021): 3639. http://dx.doi.org/10.3390/s21113639.

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Railway infrastructure plays a major role in providing the most cost-effective way to transport freight and passengers. The increase in train speed, traffic growth, heavier axles, and harsh environments make railway assets susceptible to degradation and failure. Railway switches and crossings (S&C) are a key element in any railway network, providing flexible traffic for trains to switch between tracks (through or turnout direction). S&C systems have complex structures, with many components, such as crossing parts, frogs, switchblades, and point machines. Many technologies (e.g., electrical, mechanical, and electronic devices) are used to operate and control S&C. These S&C systems are subject to failures and malfunctions that can cause delays, traffic disruptions, and even deadly accidents. Suitable field-based monitoring techniques to deal with fault detection in railway S&C systems are sought after. Wear is the major cause of S&C system failures. A novel measuring method to monitor excessive wear on the frog, as part of S&C, based on fiber Bragg grating (FBG) optical fiber sensors, is discussed in this paper. The developed solution is based on FBG sensors measuring the strain profile of the frog of S&C to determine wear size. A numerical model of a 3D prototype was developed through the finite element method, to define loading testing conditions, as well as for comparison with experimental tests. The sensors were examined under periodic and controlled loading tests. Results of this pilot study, based on simulation and laboratory tests, have shown a correlation for the static load. It was shown that the results of the experimental and the numerical studies were in good agreement.

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Journal articles on the topic 'Optical measuring machines'

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