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Journal articles on the topic 'Complex tool paths'
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1
Sarma, R., and D. Dutta. "The Geometry and Generation of NC Tool Paths." Journal of Mechanical Design 119, no. 2 (June 1, 1997): 253–58. http://dx.doi.org/10.1115/1.2826244.
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Numerically controlled milling is the primary method for generating complex die surfaces. These complex surfaces are generated by a milling cutter which removes material as it traces out pre-specified tool paths. The accuracy of tool paths directly affects the accuracy of the manufactured surface. The geometry and spacing of the tool paths impact the scallop height and time of manufacturing respectively. In this paper we propose a new method for generating NC tool paths. This method gives the part programmer direct control over the scallop height of the manufactured surface. The method also provides options to the part programmer for generating a variety of tool paths based on practical metrics such as tool path length, tool path curvature and number of tool retractions.
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Magalhães, Laurence Colares, and Joao Carlos Espindola Ferreira. "Assessment of tool path strategies for milling complex surfaces in hardened H13 steel." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 3 (February 14, 2018): 834–49. http://dx.doi.org/10.1177/0954405418755824.
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In this work, parts with complex geometry were machined in hardened H13 steel using different tool path strategies for roughing and finishing, seeking to evaluate how the tool paths and cutting conditions influence machining time, surface roughness, and geometric precision. The results showed a reduction of up to 7.8% in roughing time and 25% reduction in finishing time among the evaluated tool paths. The roughness of the complex surface depends significantly on the tool path used and is significantly impaired by the increase in the feed per tooth. The geometric deviations varied from 0.02 to 0.23 mm depending on the adopted tool path.
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Chen, Xiao Bing, and Kun Yu. "Efficient Method for Tool Path Generation Based on Region Intersection for Complex Mesh Surface Machining." Advanced Materials Research 774-776 (September 2013): 1438–41. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.1438.
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The machining efficiency of conventional section plane method is low for complex mesh surface machining. An efficient method for tool path generation based on region intersection is proposed. The mesh surface is first divided into a series of intersection regions, then vertex curvatures in perpendicular directions of tool paths are estimated by local fitting method, and variable tool path intervals are computed according to the curvatures, scallop height and cutter radius, finally redundant cutter location points are removed according to machining precision. Experiment results indicate that tool paths generated by proposed method are avail to promote machining efficiency of complex mesh surface machining.
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Chen, Zezhong C., Geoffrey W. Vickers, and Zuomin Dong. "A New Principle of CNC Tool Path Planning for Three-Axis Sculptured Part Machining—A Steepest-Ascending Tool Path." Journal of Manufacturing Science and Engineering 126, no. 3 (August 1, 2004): 515–23. http://dx.doi.org/10.1115/1.1765147.
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Three-axis CNC milling is often used to machine sculptured parts. Due to the complex surface shape of these parts, well-planned tool paths can significantly increase the machining efficiency. In this work a new principle of CNC tool path planning for 3-axis sculptured surface machining is proposed. Generic formula to calculate the steepest tangent direction of a sculptured surface is derived, and the algorithm of the steepest-ascending tool path generation is introduced. A single steepest-ascending tool path has been verified to be more efficient than a single tool path of any other type. The relationship between machining efficiency and three key variables, tool feed direction, cutter shape, and surface shape, is revealed. The newly introduced principle is used in planning tool paths of a sculptured surface to demonstrate the advantages of the steepest-ascending tool paths. This new tool path scheme is further integrated into the more advanced steepest-directed and iso-cusped (SDIC) tool path generation technique. Applications of the new tool path principle and the SDIC tool paths to the machining of sculptured parts are demonstrated.
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Wu, S. H., Ana Reis, F. M. Andrade Pires, Abel D. Santos, and A. Barata da Rocha. "Study of Tool Trajectory in Incremental Forming." Advanced Materials Research 472-475 (February 2012): 1586–91. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.1586.
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Single point incremental forming (SPIF) is an innovative flexible sheet metal forming process which can be used to produce complex shapes from various materials. Due to its flexibility, it attracts a more and more attention in the recent decades. Several studies show that besides the major operating parameters, namely feed rate, tool radius, and forming speed etc., tool path is also an important processing parameter to affect the final forming component. In view of that, the present paper studies the influence of tool paths on the work piece quality by the finite element method coupled with the Continuum Damage Mechanics (CDM) model. The formability of incremental forming in different tool paths is also analyzed.
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BERNIDO, CHRISTOPHER C., and M. VICTORIA CARPIO-BERNIDO. "WHITE NOISE ANALYSIS: SOME APPLICATIONS IN COMPLEX SYSTEMS, BIOPHYSICS AND QUANTUM MECHANICS." International Journal of Modern Physics B 26, no. 29 (September 27, 2012): 1230014. http://dx.doi.org/10.1142/s0217979212300149.
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The white noise calculus originated by T. Hida is presented as a powerful tool in investigating physical and social systems. Combined with Feynman's sum-over-all histories approach, we parameterize paths with memory of the past, and evaluate the corresponding probability density function. We discuss applications of this approach to problems in complex systems and biophysics. Examples in quantum mechanics with boundaries are also given where Markovian paths are considered.
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Nishant Kumar and Nidhi Sengar. "Pathfinder Visualizer of Shortest Paths Algorithms." International Journal for Modern Trends in Science and Technology 6, no. 12 (January 1, 2021): 479–83. http://dx.doi.org/10.46501/ijmtst061293.
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Visualizations of algorithms contribute to improving computer science education. The process of teaching and learning of algorithms is often complex and hard to understand problem. Visualization is a useful technique for learning in any computer science course. In this paper an e-learning tool for shortest paths algorithms visualization is described. The developed e-learning tool allows creating, editing and saving graph structure and visualizes the algorithm steps execution. It is intended to be used as a supplement to face-to-face instruction or as a stand-alone application. The conceptual applicability of the described e-learning tool is illustrated by implementation of Dijkstra algorithm. The preliminary test results provide evidence of the usability of the e-learning tool and its potential to support students’ development of efficient mental models regarding shortest paths algorithms. This e- learning tool is intended to integrate different algorithms for shortest path determination.
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Mineo, Carmelo, Stephen Gareth Pierce, Pascual Ian Nicholson, and Ian Cooper. "Introducing a novel mesh following technique for approximation-free robotic tool path trajectories." Journal of Computational Design and Engineering 4, no. 3 (February 16, 2017): 192–202. http://dx.doi.org/10.1016/j.jcde.2017.01.002.
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Abstract Modern tools for designing and manufacturing of large components with complex geometries allow more flexible production with reduced cycle times. This is achieved through a combination of traditional subtractive approaches and new additive manufacturing processes. The problem of generating optimum tool-paths to perform specific actions (e.g. part manufacturing or inspection) on curved surface samples, through numerical control machinery or robotic manipulators, will be increasingly encountered. Part variability often precludes using original design CAD data directly for toolpath generation (especially for composite materials), instead surface mapping software is often used to generate tessellated models. However, such models differ from precise analytical models and are often not suitable to be used in current commercially available path-planning software, since they require formats where the geometrical entities are mathematically represented thus introducing approximation errors which propagate into the generated toolpath. This work adopts a fundamentally different approach to such surface mapping and presents a novel Mesh Following Technique (MFT) for the generation of tool-paths directly from tessellated models. The technique does not introduce any approximation and allows smoother and more accurate surface following tool-paths to be generated. The background mathematics to the new MFT algorithm are introduced and the algorithm is validated by testing through an application example. Comparative metrology experiments were undertaken to assess the tracking performance of the MFT algorithms, compared to tool-paths generated through commercial software. It is shown that the MFT tool-paths produced 40% smaller errors and up to 66% lower dispersion around the mean values. Highlights This work presents a technique for generation of tool-paths from tessellated models. The technique does not introduce approximations to surface following tool-paths. Comparative metrology experiments were carried out to assess the technique. The technique produces smaller errors and lower dispersion around the mean values. The developed method is aligned with the growing use of surface mapping techniques.
9
Dong, Ming Xiao, Meng Meng Lu, Rui Chuan Li, Jun Ru Tian, Ren Yu Luo, and Ming Shi Jiang. "Application of Vega Path Tool in Visual Simulation System for Bridge Cranes." Applied Mechanics and Materials 433-435 (October 2013): 1906–9. http://dx.doi.org/10.4028/www.scientific.net/amm.433-435.1906.
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Aiming at the path sudden change and inconsistent turning of virtual vehicles in visual simulation system for bridge cranes, forklifts virtual paths are created by using path and navigator modules in Lynx interface based on the application principles of path and navigator in Vega software. Then, forklifts visual paths are edited to ensure the natural and fluent movements of forklifts by choosing spline navigator, setting smaller smoothing threshold and smaller spline tension parameters in Path Tool. Finally, combining working cycle requirements of loading and unloading goods for bridge cranes, continuous motions of several forklifts are realized by calling the path navigation library functions of Vega Software in VC++. Therefore, virtual vehicles complex paths are created and disadvantages of fixed path for virtual vehicles in visual simulation system are solved.
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Clarkson, P. John, Caroline Simons, and Claudia Eckert. "Predicting Change Propagation in Complex Design." Journal of Mechanical Design 126, no. 5 (September 1, 2004): 788–97. http://dx.doi.org/10.1115/1.1765117.
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In redesign and design for customization, products are changed. During this process a change to one part of the product will, in most cases, result in changes to other parts. The prediction of such change provides a significant challenge in the management of redesign and customization of complex products where many change propagation paths may be possible. This paper reports on an analysis of change behavior based on a case study in Westland Helicopters of rotorcraft design; the development of mathematical models to predict the risk of change propagation in terms of likelihood and impact of change; and the development of a prototype computer support tool to calculate such information for a specific product. With knowledge of likely change propagation paths and their impact on the delivery of the product, design effort can be directed towards avoiding change to “expensive” sub-systems and, where possible, allowing change where it is easier to implement while still achieving the overall changes required.
11
Brink, Tove. "Managing uncertainty for sustainability of complex projects." International Journal of Managing Projects in Business 10, no. 2 (April 4, 2017): 315–29. http://dx.doi.org/10.1108/ijmpb-06-2016-0055.
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Purpose The purpose of this paper is to reveal how management of uncertainty can enable sustainability of complex projects. Design/methodology/approach The research was conducted from June 2014 to May 2015 using a qualitative deductive approach among operation and maintenance actors in offshore wind farms. The research contains a focus group interview with 11 companies, 20 individual interviews and a seminar presenting preliminary findings with 60 participants. Findings The findings reveal the need for management of uncertainty through two different paths. First, project management needs to frontload important issues, which results in the need to use resources much earlier than noted in the usual stage gate approach. Additionally, the base organisation needs the capacity to both explore and exploit important issues. In the summarisation of findings, a tool is developed for the two paths to join efforts. Research limitations/implications Further research is needed to reveal the generalisability of the findings in other complex project contexts containing “unknown unknowns”. Practical implications The research leads to the development of a tool for uncertainty management for sustainability of complex projects, which is termed “UMSCoPS”. The model provides a guide for insight and understanding of uncertainty management. Originality/value The previous knowledge on managing uncertainty for sustainability of complex projects is enhanced regarding the uncertainty management in complex projects. The approach to uncertainty has returned to the original notion of the “unknown unknowns”, and project management thereby leaves the widely used stage gate approach. The developed tool provides a fresh understanding of the challenges of uncertainty.
12
Meyghani, Bahman, and Mokhtar Awang. "A Novel Tool Path Strategy for Modelling Complicated Perpendicular Curved Movements." Key Engineering Materials 796 (March 2019): 164–74. http://dx.doi.org/10.4028/www.scientific.net/kem.796.164.
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Curved surfaces have been widely used in engineering applications such as friction stir welding (FSW), 5 axis CNC machining, and other processes. Therefore, the development of the finite element modelling of the complicated geometries has created a need to determine efficient tool paths. Previous finite element models modelled the single point movement of the tool. However, in industrial applications such as aerospace, mould and die, etc. the movement of the tool is complex. Proper determination of the tool path can lead to substantial savings of the process time, improvement of the workpiece surface quality and the improvement of the tool life, thereby leading to overall cost reduction and higher productivity. This paper presents a new approach for the determination of efficient tool paths in finite element modelling by using ABAQUS® software. VDISP user defined subroutine is used in order to define the complex curved movement of the tool. The results indicate that the method is appropriate for modelling of the tool path, and the tool always has a perpendicular position to the surface. Therefore, the method can be suitable for increasing the application of the finite element modelling in various industries.
13
Chen, Zuo Yue, Xiao E. Wang, and Mei Yang. "Complex Parts Design Based on Macro Programming." Applied Mechanics and Materials 635-637 (September 2014): 1386–89. http://dx.doi.org/10.4028/www.scientific.net/amm.635-637.1386.
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CNC programming is from the part drawings to get the whole process of NC program, the core of the work is to generate tool paths, and then dispersed into the knife sites generated by the NC post-processing program. As one of the key technologies of CNC machining, the preparation of the efficiency and quality of its programs largely determine the processing accuracy and production efficiency. Engineering approach of this research complex part features macro programming design.
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Grigoriev, Sergey N., Andrey A. Kutin, and Mikhail Turkin. "Advanced CNC Programming Methods for Multi-Axis Precision Machining." Key Engineering Materials 581 (October 2013): 478–84. http://dx.doi.org/10.4028/www.scientific.net/kem.581.478.
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This paper presents a method to simultaneously increase the accuracy and decrease the calculation time for complex tool path programming in multi-axis machining centers. Examples of complex parts requiring such complex tool paths include various kinds of turbine blades, pump-forcing augers, teeth surfaces, etc. It explains the creation of topological structures on the basis of analytical spline curves with floating range definitions. The method for tool path calculation accommodates the specific requirements for multi-axis milling. The algorithms developed are the foundation for the CAD/CAM software that allows for NC programming and machining on 5-axis centers employing any design model. Industrial tests reveal a 70-80% reduction of NC programming time of parts with complex surfaces, reduced machining time of approximately 40-50% using basic high-speed cutting methods and custom-made tools. The advanced methods of NC programming result in substantially increasing machining accuracy.
15
Pan, Li Bo, Hong Chuan Zhu, Ze Hong Lei, and Zhi Jian Zhang. "Experimental Researches on Nonlinear Strain Paths Forming for Dual Phase Steel." Advanced Materials Research 1004-1005 (August 2014): 209–13. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.209.
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Strain paths during sheet metal forming are always complex and nonlinear. Forming limit diagram (FLD) is a common method to determine failure in the past decades. However, it is only suitable for linear strain path condition. Regarding dual phase steel DP780, a special experiment was designed and carried out on Zwick Cupping equipment to get nonlinear strain paths. And the strain status was analyzed in FLD. It was found that FLD cannot predict failure precisely in this case. A new approach proposed by Stoughton and Yoon which based on polar effective plastic strain was introduced to analyze this nonlinear strain paths condition, the result is in good agreement with experiment, which indicated that Polar Effective Plastic Strain Diagram was an effective and precise tool to determine failure especially for complex nonlinear strain paths forming.
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Abrams, Michael. "Simply Complex." Mechanical Engineering 128, no. 01 (January 1, 2006): 28–31. http://dx.doi.org/10.1115/1.2006-jan-2.
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This article focuses on industrial benefits of computer-aided manufacturing (CAM). With the ever multiplying functionality of both machine and software, the challenge for CAM programmers has become one of ‘how do you keep things simple and at the same time complex.’ Machine makers now work directly with CAM programmers so customers can get as much from their machines as possible. NX's newest software offers tool paths that are smoother and smarter, and take into account the material that's being cut, to better avoid collision. But the key to optimization is understanding every aspect of a machine, down to when and how it vibrates. Simulations let programs like NX and Vericut know every stage of a part while it is on the machine and this allows users to eliminate one of the most tedious of time drainers: documentation. NX software as well as Vericut automatically outputs documentation for the entire process.
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Skjoedt, M., M. H. Hancock, and N. Bay. "Creating Helical Tool Paths for Single Point Incremental Forming." Key Engineering Materials 344 (July 2007): 583–90. http://dx.doi.org/10.4028/www.scientific.net/kem.344.583.
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Single point incremental forming (SPIF) is a relatively new sheet forming process. A sheet is clamped in a rig and formed incrementally using a rotating single point tool in the form of a rod with a spherical end. The process is often performed on a CNC milling machine and the tool movement is programed using CAM software intended for surface milling. Often the function called profile milling or contour milling is applied. Using this milling function the tool only has a continuous feed rate in two directions X and Y, which is the plane of the undeformed sheet. The feed in the vertical Z direction is done in the same angular position in the XY plane along a line down the side of the work piece. This causes a scarring of the side and also results in a peak in the axial force when the tool is moved down. The present paper offers a solution to this problem. A dedicated program uses the coordinates from the profile milling code and converts them into a helical tool path with continuous feed in all three directions. Using the helical tool path the scarring is removed, the part is otherwise unchanged and a major disadvantage of using milling software for SPIF is removed. The solution is demonstrated by SPIF of three different geometries: a pyramid, a cone and a complex part.
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Takasugi, Keigo, Naoki Asakawa, and Yoshitaka Morimoto. "A Surface Parameter-Based Method for Accurate and Efficient Tool Path Generation." International Journal of Automation Technology 8, no. 3 (May 5, 2014): 428–36. http://dx.doi.org/10.20965/ijat.2014.p0428.
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Along with the increasing need for multi-axis and multi-tasking machining tools for the machining of complex free surfaces, the importance of CAM applications related to the accuracy of the free surfaces has increased dramatically. The machining accuracy and surface integrity of a product depends not only on the performance of the machining tool itself but also on the tool path generated by CAM. At present, there is a trade off between numerical calculation errors and cost in CAM. There is no calculation method that satisfies both sides. Of particular importance is the fact that the cost increases exponentially with the rank of the free surface. Therefore, this paper proposes a new method of generating tool paths efficiently; it generates tool paths directly from 2-dimensional parametric space by using the parametric surface defined as a polynomial. We confirm that this method can reduce the cost and that the tool path can be generated by means of a simple calculation process, without considering singular points. Moreover, since commercial CAM kernels cannot accommodate to our method, we design and implement a new CAM kernel that can access the parametric surface directly in order to develop this method.
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Beudaert, Xavier, Pierre Yves Pechard, and Christophe Tournier. "5-Axis Flank Milling Tool Path Smoothing Based on Kinematical Behaviour Analysis." Advanced Materials Research 223 (April 2011): 691–700. http://dx.doi.org/10.4028/www.scientific.net/amr.223.691.
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In the context of 5-axis flank milling, the machining of non-developable ruled surfaces may lead to complex tool paths to minimize undercut and overcut. The curvature characteristics of these tool paths generate slowdowns affecting the machining time and the quality of the machined surface. The tool path has to be as smooth as possible while respecting the maximum allowed tolerance. In this paper, an iterative approach is proposed to smooth an initial tool path. An indicator of the maximum feedrate is computed using the kinematical constraints of the considered machine tool, especially the maximum velocity, acceleration and jerk. Then, joint coordinates of the tool path are locally smoothed in order to raise the effective feedrate in the area of interest. Machining simulation based on a N-buffer algorithm is used to control undercut and overcut. This method has been tested in flank milling of an impeller and can be applied in 3 to 5-axis machining.
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Jacso, Adam, Tibor Szalay, Juan Carlos Jauregui, and Juvenal Rodriguez Resendiz. "A discrete simulation-based algorithm for the technological investigation of 2.5D milling operations." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 1 (February 7, 2018): 78–90. http://dx.doi.org/10.1177/0954406218757267.
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Many applications are available for the syntactic and semantic verification of NC milling tool paths in simulation environments. However, these solutions – similar to the conventional tool path generation methods – are generally based on geometric considerations, and for that reason they cannot address varying cutting conditions. This paper introduces a new application of a simulation algorithm that is capable of producing all the necessary geometric information about the machining process in question for the purpose of further technological analysis. For performing such an analysis, an image space-based NC simulation algorithm is recommended, since in the case of complex tool paths it is impossible to provide an analytical description of the process of material removal. The information obtained from the simulation can be used not only for simple analyses, but also for optimisation purposes with a view to increasing machining efficiency.
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She, Chen Hua, Wen Yuh Jywe, and Jheng Jie Huang. "Measuring Path without Tool Center Point Function for B-Type Five-Axis Machine Tool." Applied Mechanics and Materials 284-287 (January 2013): 493–97. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.493.
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Five-axis machine tools with three linear axes and two rotary axes can produce complex products with free-form surfaces requiring a high degree of precision. However, motion errors of each axis and its assembly error are accumulated in the positioning error of the cutting tool relative to a workpiece. There are many devices reported in the literature on the identification of kinematic errors based on the measurement of the motion error. According to the measurement paths in the ISO draft, ISO/CD 10791-6, the kinematic tests can be applicable to different configurations of five-axis machine tools. However, the advanced controller with tool center point (TCP) function is required while performing kinematic tests. This paper proposed the methodology of generating measurement path without TCP function for B-type five-axis machine tool. The developed module can transform the measuring path into an NC program used for lower hand controller. Verification using VERICUT solid cutting simulation software demonstrated the veracity of the generated five-axis NC code. The proposed methodology is applicable in a wide range of five-axis machine tool configurations; however, further testing with actual measuring applications will be required for further verification.
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Sudo, Masako. "Advanced Control Technologies for 5-Axis Machining." International Journal of Automation Technology 1, no. 2 (November 5, 2007): 108–12. http://dx.doi.org/10.20965/ijat.2007.p0108.
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Demand for 5-axis machine tools has grown rapidly with the appearance of high-performance machines and growing requirements for high-efficiency to enhance competitiveness. To meet market needs, FANUC provides innovative CNCs, including the FS30i-A and FS31i-A5, that control up to 24 axes simultaneously with maximum paths of 10 enabling high-speed and high-precision multiple-axis and path control. FANUC's wide-ranging functions developed for powerful 5-axis machining include tool center point control and tilted working plane command, which enable high-precision complex shape machining minimizing changeover. Nano smoothing, interpolation for generating smooth curves on a nanometer scale, enables high-quality workpiece machining. 3D interference checking enhances the safety of machines whose motion has become increasingly complex. Operability has also been improved to facilitate programming and simulation for 5-axis machining. This report presents the latest control technologies maximizing 5-axis machine tool performance.
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Jamshidi, Babak, Farhad Haji Aboutalebi, Mahmoud Farzin, and Mohammad Reza Forouzan. "Numerical Prediction of Damage Evolution in Sheet Metal Forming Processes with Nonlinear and Complex Strain Paths." Key Engineering Materials 473 (March 2011): 653–58. http://dx.doi.org/10.4028/www.scientific.net/kem.473.653.
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Various thin-walled parts with fairly complex shapes are produced from sheet metals such as automotive panels and other structural parts. In these processes, damage and fracture may be observed on the work piece, and formability plays a fundamental role. Therefore, determination of forming limits and prediction of rupture modes in these operations is very important for process design engineers. In this paper, first, based on plane stress elasto-plasticity and finite strain theories a fully coupled elastic-plastic-damage model is used to predict damage evolution in one sheet metal forming process with nonlinear and complex strain paths. As the plane stress algorithm is valid for thin sheet metals and finite strain theory is recommended for large deformations or rotations, the model is able to quickly predict both deformation and damage behaviour of the parts with nonlinear and complex strain paths. The numerical simulations are compared with experimental tests. Comparison of the numerical and experimental results shows that the proposed damage model is accurate for various forming conditions. Hence, it is concluded that finite element method combined with continuum damage mechanics, can be used as a reliable and rapid tool to predict damage evolution in sheet metal forming processes with nonlinear and complex strain paths.
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Li, Hui Ying, and Liang Ji Chen. "Cutter Contacting Machining Paths Generation Method for Surface Flat-End Milling." Applied Mechanics and Materials 536-537 (April 2014): 1630–33. http://dx.doi.org/10.4028/www.scientific.net/amm.536-537.1630.
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In order to enhance machining precision of complex surfaces with a flat-end cutter, the generating method of cutter contacting (CC) paths is presented in this article. With the method of coordinate transformation, effective machining radius of a flat-end cutter had been deduced and the step-over formed by two adjacent CC paths were implemented. The parameter increment along the CC path interval direction was calculated by using geometric analysis of the local area of CC point. The corresponding NURBS path of tool center points including knot vector and controlling points was obtained from the cutter contacting points.
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Chang, Han-Jui, Shang-Liang Chen, and Po-Yi Lee. "Using the direct cutting paths approach on aluminum alloy cone frustum part for evaluating a five-axis machine tool with Taguchi method." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 231, no. 5 (January 17, 2017): 881–88. http://dx.doi.org/10.1177/0954405416673096.
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It is difficult to compare five-axis machine tools complex analysis against independent motion of multi-type machines; more specifically, there has been no breakthrough involving the interaction effect factors from cutting analysis. Therefore, the defining and quantifying of data are important in assessing the overall performance of five-axis machine tools, and allow for the evaluation of each subsequent interaction motion analysis. Among various cutting test models, the machining of a cone frustum as specified in National Aerospace Standard 979 and International Standard Organization 10791-7 is widely accepted as a performance test standard for five-axis machining centers. Although it gives a demonstration of the machine’s machining performance, it is generally difficult to identify the overall effects of kinematic interaction within the profile of the finished workpiece. This is new approach to a previously defined 10 direct cutting paths method to evaluate the performance of each cone frustum motion, and it is not limited to only evaluating single direction or displacement on a five-axis machine tool. Among the 10 cutting paths, four of them are real five-axis cutting and the remaining paths are non-real five-axis cutting. This allowed the test of four to five mixed external forces at the same time, which the instrument is not able to measure. This article further proposes to calculate the factorial effect of interaction, based on the Taguchi method signal-to-noise ratio, mechanical advantage, and Variables separable model, which allows for the comparison of the performance of different five-axis machine tool types.
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Chen, Liang Ji, Hui Ying Li, and Hai Jun Zhang. "Study on Tool Path Generation and Direct Interpolation Method." Advanced Materials Research 945-949 (June 2014): 1657–60. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.1657.
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At present, Non-Uniform Rational B-Spline (NURBS) curves are mostly used to generate arbitrary contour of a complex shape in the CAD field. In this article, a new method with NURBS technology is presented and realized in a location and federate controlling system. In the method, the tool paths and the cutter locations (CL) were represented into NURBS curves based on the same knot vector. The above CL data was firstly calculated and then transformed to five motion commands of five axes of machine through the real-time post-procession algorithm. The acceleration/deceleration controlling method is also presented to avoid the impact of machine. The proposed 5-axis spline interpolation method is realized and the experimental result of machining shows that the method is valid.
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Li, Hui Ying, and Liang Ji Chen. "CC Path Generation Method Based on Cutting Shape of Flat-End Cutter." Applied Mechanics and Materials 621 (August 2014): 157–61. http://dx.doi.org/10.4028/www.scientific.net/amm.621.157.
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The calculating algorithm for Cutter Contacting (CC) paths is proposed in this article to enhance machining precision of complex surfaces with a flat-end cutter. With the style of coordinate transformation, effective cutting shape and equavellent machining radius of a flat-end cutter had been calculated and deduced, and the step-over distance formed by two adjacent CC paths were also obtained. The corresponding NURBS path of tool center points including knot vector and controlling points was obtained from the cutter contacting points.The parameter increment along the CC path interval direction was calculated by using geometric analysis of the local area of CC point.
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Moravčíková, Jana, and Peter Pokorný. "Design of Complex Component for Determination of a CNC Milling Machines Accuracy." Key Engineering Materials 703 (August 2016): 22–26. http://dx.doi.org/10.4028/www.scientific.net/kem.703.22.
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The article is focused on the design of complex component to determine competence CNC milling machines designed to produce shapes with geometric tolerances by observing the shape, orientation and position of the standard EN ISO 1101. 3D model of a technological process for the production of complex components, it will contain the complete design of tools and cutting parameters for individual milling strategy, select clamping and workpiece material, a preview of the generated routing strategies and paths cut surface after each of their simulated. For milling machines with the so-called measurement system for machine OMM (On Machine Measurement), the proposal for a comprehensive parts serve as a reference in determining the accuracy of their measurements of geometric and dimensional tolerances. The main activity of systems OMM is the replace of the tool clamped in the spindle of milling machines with special touch probe which senses by the touch surface contours of produced parts.
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Chen, Ying, and Yi Qiang Wang. "Isoscallop of Self-Adaptive Tool Orientation with Toroidal Cutter under Optimum Orientation of MCPs." Advanced Materials Research 562-564 (August 2012): 713–16. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.713.
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End-milling of free-form surfaces on 5-sxis NC tools is a complex problem which has been studied by a large number of research scientists. When end-milling non-convex surfaces, there is a risk of interference between the tool and the surface. This paper presents a new approach to generate gouging-free tool path for constant scallop-height machining using 5-axis toroidal milling. Based on second-order approximations of the machined strip width, we present locally optimal cutting positions for cutting directions. The largest machined strip width of iso-scallop and the corresponding gouging-avoidance tool orientation are calculated. In the cutter path generation procedures, the master cutter paths have been chosen from the minimum curvature loci of the surface. The tool path generated by this method are also compared with that of the long edge of surface as the MCP, the results of simulation show that the method can yield a reduction in line segments of tool path . Velocity curve and acceleration curve are smoother.
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PANOPOULOS, D., K. METAXIOTIS, D. PTOCHOS, C. LIGOURAS, and M. SKLAVENITI. "SOLVING PRODUCTION SCHEDULING PROBLEMS USING ADVANCED MODEL CHECKING TOOLS." Journal of Advanced Manufacturing Systems 05, no. 02 (December 2006): 209–32. http://dx.doi.org/10.1142/s0219686706000832.
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The main scope of this paper is the implementation of a method for production scheduling, using advanced model checking tools. This method makes use of timed automata in order to model complex production scheduling problems like the job-shop and the open-shop scheduling problems. By modeling scheduling problems using timed automata, feasible schedules correspond then to paths in the automata, while finding the optimum schedule corresponds to finding the shortest path in an automaton. Several algorithms and heuristics have been proposed to find the shortest paths in timed automata, which are mainly based on the implementation of graph algorithms that search the transition graph. In our work, an advanced model design and checking tool, called Uppaal, has been used to implement and test the above method on a number of different models and to show the effectiveness of such an approach in terms of finding optimal, or near to optimal, schedules in polynomial time, even for large scale problems.
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Wu, Yu Hou, Qiang Gao, and De Hong Zhao. "UG and VERICUT-Based Processing of Special-Shaped Stone Samples." Advanced Materials Research 415-417 (December 2011): 924–28. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.924.
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In order to verify the processability of a special-shaped stone machining center’s horizontal working portion, to process complex stone products. On the basis of analysis of the physical characteristics of diamond cutting tool and stone, create a model and use UG software to program, making this machine center’s dedicated post processor. Simulate NC code that is generated with VERICUT software, optimize the cutting parameters and analyse its surface quality. Avoid interference in the program, gouge, collisions and other phenomena by adjusting the tool axis’s attitude and the tool paths. Actual process verified the reliability of the program, technological parameter is rational, quality of the parts’ surface is well. Make precisely outline and tool wear is small, overcome the drawbacks of CNC system, get a higher efficiency.
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Meier, Horst, Jan Brüninghaus, B. Buff, Alfred Hypki, Adrian Schyja, and V. Smukala. "Tool Path Generation for Free Form Surfaces in Robot-Based Incremental Sheet Metal Forming." Key Engineering Materials 410-411 (March 2009): 143–50. http://dx.doi.org/10.4028/www.scientific.net/kem.410-411.143.
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This paper describes a new development in incremental, robot-based sheet metal forming (Roboforming). Roboforming is a dieless sheet metal forming process which ensures cost-effective manufacturing of prototype parts and small batches. Its principle is based on flexible shaping by means of a freely programmable path synchronous movement of two industrial robots driving work-piece independent forming tools. The final shape is produced by the incremental inward motion of the forming tool in depth direction and its movement along the contour in lateral direction on a heli-cal path. The supporting tool, with its simple geometry, holds the sheet on the backside by moving syn¬chronously along the outer contour, at constant depth. In this way no special dies are needed. For mil¬ling machines, which are used in numerous incremental forming approaches, CAD/CAM inter¬faces exist for generating necessary tool paths. For industrial robots only a few simple solutions emerge, which do not have the potential of classical CAD/CAM interfaces and are unusable for co-operating robot systems. While the two coupled robot programs can be programmed manually for simple geometries, this approach does not work for complex geometries. In this paper a further de-velopment in robot programming systems is presented that is now able to derive helical tool paths from any CAD file and generate two cooperating programs for the forming and the sup¬porting tools. The helixes pitch is variable and dependent on the geometry’s wall angle. To increase the part accu¬racy a process database is used, that stores relevant information about the process pa¬rameters, sensor data and used equipment. Based on this information strategies for increasing the part accuracy can be applied.
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Yan, Cao Qing, Jun Zhao, Yue En Li, and Shi Guo Han. "Experimental Research on Surface Roughness in High Speed Milling of Complex Surface Mold Steel." Materials Science Forum 626-627 (August 2009): 123–28. http://dx.doi.org/10.4028/www.scientific.net/msf.626-627.123.
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Complex surface mold has been widely used in various industries, and high efficiency and high quality can been achieved through high-speed CNC milling processing. Surface roughness including transverse and longitudinal roughness is an important criterion for mold quality. A high-speed milling experiment was performed in mold steel P20 using cemented carbide ball-end mill to investigate the surface roughness. The effects of process parameters on roughness including spindle speed, feed per tooth and radial cutting depth were examined, and an analysis on the mechanism for two kinds of roughness of different tool paths was finished. The experimental results show that the longitudinal roughness improve obviously while the spindle speed and the feed per tooth increase on the high-speed conditions, and the transverse roughness increase significantly when the radial cutting depth increases. And for a smaller roughness value, the tool path should be selected along the direction in which the curvature changes evidently.
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Repper, Julia, Markus Niffenegger, Steven van Petegem, Werner Wagner, and Helena van Swygenhoven. "In Situ Biaxial Mechanical Testing at the Neutron Time-of-Flight Diffractometer POLDI." Materials Science Forum 768-769 (September 2013): 60–65. http://dx.doi.org/10.4028/www.scientific.net/msf.768-769.60.
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Complex strain paths are often applied to materials during production processes. This paper shows the first successful in-situ biaxial mechanical tests during neutron diffraction performed on a cruciform steel sample and reports on the differences compared to uniaxial deformation. Digital image correlation is demonstrated to be an appropriate tool to monitor spatially resolved the macroscopic straining. The new, modular biaxial machine that will be installed at the neutron diffractometer POLDI is presented.
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Kreimeier, D., B. Buff, C. Magnus, V. Smukala, and J. Zhu. "Robot-Based Incremental Sheet Metal Forming – Increasing the Geometrical Accuracy of Complex Parts." Key Engineering Materials 473 (March 2011): 853–60. http://dx.doi.org/10.4028/www.scientific.net/kem.473.853.
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This paper describes new developments in an incremental, robot-based sheet metal forming process (Roboforming) for the cost-effective production of sheet metal components for limited-lot productions and prototypes. The paper presents strategies in robot based incremental sheet metal forming for the force controlled forming of complex parts. These parts can consist of features such as steep flanks or convex/concave alternating surfaces and they are mostly formed with a local support tool which substitutes a full die. The strategies were developed in a cooperative project funded by the German Federal Ministry of Education and Research and the German Research Foundation. Approaches to increase the part accuracy of complex parts are presented. One approach concentrates on a servo loop, consisting of sensors and a programming system. It guarantees higher part accuracies by measuring the deviations between a formed part and its target geometry. These deviations are used to derive corrected tool paths. The abdication of a partial or full die leads to a larger influence of the free compliant sheet area surrounding the formed part. Because of that the geometry shifts away from the forming tool and it cannot be formed completely. Another approach to increase the part accuracy by reinforcing this free sheet area is also presented.
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Tutunea-Fatan, O. Remus, and Hsi-Yung Feng. "Determination of Geometry-Based Errors for Interpolated Tool Paths in Five-Axis Surface Machining." Journal of Manufacturing Science and Engineering 127, no. 1 (February 1, 2005): 60–67. http://dx.doi.org/10.1115/1.1831285.
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Five-axis computer numerical control (CNC) machining is characterized with a multitude of errors. Among them an important component comes from the computer-aided manufacturing software known as the geometry-based errors. A new and accurate method to determine these errors is presented in this paper as opposed to the conventional chordal deviation method. The present method allows establishing the exact linearly interpolated tool positions between two cutter contact points on a given tool path, based on the inverse kinematics analysis of the machine tool. A generic procedure has been developed to ensure wide applicability of the proposed method. Analytical derivation of the geometry-based errors provides insights regarding the origin of these errors and their affecting parameters. Due to the highly non-linear characteristics of the problem, analytical solutions can only be obtained for simple surface geometry. Numerical computation is able to determine the errors for general surface shapes but it would be difficult to uncover further insightful information from the calculated error values. Besides the local surface geometry, the configuration of the kinematic chain of the CNC machine has been found to be the primary factor controlling the resulting value and type of the geometry-based errors. Implementations with a typical complex free-form surface demonstrated that the conventional chordal deviation method was not reliable and could significantly underestimate the geometry-based errors.
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Bailey, T., M. A. Elbestawi, T. I. El-Wardany, and P. Fitzpatrick. "Generic Simulation Approach for Multi-Axis Machining, Part 1: Modeling Methodology." Journal of Manufacturing Science and Engineering 124, no. 3 (July 11, 2002): 624–33. http://dx.doi.org/10.1115/1.1468863.
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This paper presents a new methodology for analytically simulating multi-axis machining of complex sculptured surfaces. A generalized approach is developed for representing an arbitrary cutting edge design, and the local surface topology of a complex sculptured surface. A NURBS curve is used to represent the cutting edge profile. This approach offers the advantages of representing any arbitrary cutting edge design in a generic way, as well as providing standardized techniques for manipulating the location and orientation of the cutting edge. The local surface topology of the part is defined as those surfaces generated by previous tool paths in the vicinity of the current tool position. The local surface topology of the part is represented without using a computationally expensive CAD system. A systematic prediction technique is then developed to determine the instantaneous tool/part interaction during machining. The methodology employed here determines cutting edge in-cut segments by determining the intersection between the NURBS curve representation of the cutting edge and the defined local surface topology. These in-cut segments are then utilized for predicting instantaneous chip load, static and dynamic cutting forces, and tool deflection. Part 1 of this paper details the modeling methodology and demonstrates the capabilities of the simulation for machining a complex surface. Part 2 details both the model calibration procedure and discusses a case study of process optimization through feed rate scheduling.
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Han, Guang Chao, Ming Sun, Hai Ou Zhang, and Gui Lan Wang. "Research on the Robotic Free Abrasive Polishing System for the Rapid Spray Metal Tooling." Key Engineering Materials 373-374 (March 2008): 770–73. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.770.
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In the rapid spray metal tooling, metal film is spray-formed on the substrate and supported under the back, which will act as the working surface of the rapid metal tool finally. So the finishing process for the sprayed metal film is important to the quality and the lifecycle of the rapid metal tool. The finishing of the metal mould is frequently carried out manually, these kinds of operations are iterative, time consuming and require experience. Automation can introduce cost reduction minimizing production times on such manual finishing operations. This paper presents a robotic polishing system with free abrasive for the finishing of the rapid spray metal tool, which is consisted of a six-degree-of-freedom industrial robot manipulator, a high speed electrical polishing spindle and a numerical swivel table. Soft polishing pad and free abrasive are also selected for the robotic polishing system. The path planning is so important to the robotic polishing system that a partition & flexible path mapping method basing on UG CAM is developed to generate the uniform robotic polishing path on the complex mould surface. UG/Open GRIP programming module is used to generate the driving paths with different path intervals on the predesigned plane for each partitioned part. When the driving paths are projected to the mould curved surface, the uniform polishing paths with NC code can be generated by the multi-axis CAM module of the UG. And the path with NC code can then be transformed to the robotic polishing path. According to the elastic deformation and the abrasion of the soft polishing tool, the robotic polishing path should be adjusted to keep the smooth polishing process by offsetting the pre-compressed value and the abrasive compensation value along the polishing axis direction. Technical parameters of the robotic polishing process are also optimized through the experiments. Finally, the rapid metal punch mould is finished to test the robotic polishing system.
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Lopes, Wellington, Elaine Carballo Siqueira Corrêa, Haroldo Béria Campos, Maria Teresa Paulino Aguilar, and Paulo Roberto Cetlin. "Evaluation of the Work-Hardening of Brass Sheets Following Strain Path Changes." Advanced Materials Research 89-91 (January 2010): 353–58. http://dx.doi.org/10.4028/www.scientific.net/amr.89-91.353.
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The strain paths followed by metals during sheet forming can be quite complex, especially when successive forming steps are involved. The work hardening of metals associated with these strain paths differs from that caused only by monotonic straining, such as simple tension or compression. It is important to have an adequate description of the work hardening of the material under processing, especially when numerical simulations of the forming are used. The experimental evaluation of the effect of strain path changes on the material work hardening is usually performed through tensile testing following the strain path changes. This technique, however, demands complex machining operations of the formed sheets and the imposed strain is severely limited by impending necking. The present paper utilizes simple shear as a tool for the determination of the work hardening of CuZn34 brass sheets following various strain path changes associated with combinations of different modes of deformation such as rolling, tension, cyclic and forward shears. The results indicate that the cyclic shearing delays the occurrence of plastic instabilities for brass previously tensioned, occurring the opposite for final monotonic shearing. These phenomena were correlated with the probable microstructural evolution of the CuZn34 brass.
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Jang, Peter, Kwanghee Jung, and Mario Beruvides. "Application of IRT Models to Selection of Bidding Paths in Financial Transmission Rights Auction: U.S. New England." Energies 13, no. 13 (June 30, 2020): 3325. http://dx.doi.org/10.3390/en13133325.
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This paper explores a way to apply Item Response Theory (IRT), one of the popular statistical methodologies in measurement and psychometrics, to evaluate Financial Transmission Rights (FTR) paths in the U.S. electricity market. FTR is an energy derivative product to hedge congestion cost risks inherent in constrained transmission lines. In New England, with about 1200 pricing locations, the theoretical combinations of FTR paths amount to 1.4 million in prevailing flows alone. With capital constraints, it is imperative that FTR market participants build the capability to evaluate FTR paths to bid on. IRT provides a framework of how well tests work, and how individual items work on tests, estimating respondents’ latent abilities, and individual item parameters. IRT is utilized to analyze historical electricity data of 2019 for a daily congestion cost of eight customer load zones and one hub in the U.S., New England, for the evaluation of FTR paths. In the analysis, an item represents an FTR path, while item difficulty, item discrimination, and a latent trait variable for the path correspond to the path profitability, risk level, and daily congestion ability, respectively. This paper explores the experimental procedures by which IRT, a psychometric tool, may also be applicable in complex energy markets, providing a consistent and standardized analytical framework to address the issues of selection and prioritization among multiple opportunities. FTR path evaluation is conducted in three steps to determine bid priority paths in FTR auctions: parameter significance tests, ranking on path profitability and risk level, and weighting scores of individual rankings on the two criteria.
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Padilha, Paulo Eduardo França, and José Roberto de França Arruda. "Comparison of Estimation Techniques for Vibro-Acoustic Transfer Path Analysis." Shock and Vibration 13, no. 4-5 (2006): 459–67. http://dx.doi.org/10.1155/2006/901798.
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Vibro-acoustic Transfer Path Analysis (TPA) is a tool to evaluate the contribution of different energy propagation paths between a source and a receiver, linked to each other by a number of connections. TPA is typically used to quantify and rank the relative importance of these paths in a given frequency band, determining the most significant one to the receiver. Basically, two quantities have to be determined for TPA: the operational forces at each transfer path and the Frequency Response Functions (FRF) of these paths. The FRF are obtained either experimentally or analytically, and the influence of the mechanical impedance of the source can be taken into account or not. The operational forces can be directly obtained from measurements using force transducers or indirectly estimated from auxiliary response measurements. Two methods to obtain the operational forces indirectly – the Complex Stiffness Method (CSM) and the Matrix Inversion Method (MIM) – associated with two possible configurations to determine the FRF – including and excluding the source impedance – are presented and discussed in this paper. The effect of weak and strong coupling among the paths is also commented considering the techniques previously presented. The main conclusion is that, with the source removed, CSM gives more accurate results. On the other hand, with the source present, MIM is preferable. In the latter case, CSM should be used only if there is a high impedance mismatch between the source and the receiver. Both methods are not affected by a higher or lower degree of coupling among the transfer paths.
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Luo, Fang, Xiangdong Dai, and Yanli Huang. "The Analysis of Evolutionary Path of Research Topics on the Field of Visualization of International Cultural Heritage Information Since the 21st Century." E3S Web of Conferences 236 (2021): 05074. http://dx.doi.org/10.1051/e3sconf/202123605074.
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This paper has retrieved 979 literatures in the field of visualization of cultural heritage information between 2000 and 2020 from Web Of Science core collection. With the keys words as the unit of analysis, cluster analysis and co-word analysis as the research methods and SciMAT as the tool, it has identified research highlights and evolution paths in different periods. The research has found that research topics vary a lot in different periods. Part of the thematic studies are strongly related in sequence, the evolutionary relations between topics gradually become complex in the middle and latter period, and 5 evolution paths are presented in general. System is the main research interests and will continue to be the research highlights. Museum becomes a fundamental topic with great potential in the field after continuous integration and regeneration. 3-D visualization, with the largest time span and various research contents, is the fundamental topic in the field.
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Idrissov, Agzam, Pedro Parraguez, and Anja M. Maier. "Tracing Paths and Connecting Multiple Design Domains: An Information Visualisation Approach to Product Architecture Modelling." Proceedings of the Design Society: International Conference on Engineering Design 1, no. 1 (July 2019): 3021–30. http://dx.doi.org/10.1017/dsi.2019.309.
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AbstractVisual representation of product architecture models is crucial in complex engineering systems design. However, when the number of entities in a model is large and when multiple levels of hierarchies are included, visual representations currently in use need to be more intuitive. As such, improved visual representations that enable better system overview and better communication of essential product- related information among design participants are needed. This paper uses interactive information visualisation techniques – collapsible hierarchical tree, edge bundling and alluvial diagram – and provides the foundations of a computerised tool that improves the traceability of connections between design domains, including stakeholders, requirements, functions, behaviours and structure. The case of a cleaning robot is used as an illustrative example. The approach supports designers by providing an enhanced overview during the development of complex product architecture models, in particular in the communication with external stakeholders, in the identification of change propagation paths across several design domains, and in capturing the design rationale of previous design decisions.
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Barberis, Lorenzo, and Nathan J. McNeese. "Intelligent and Human-Centered Clinical Checklists: A Voice Interface for Virtualized Clinical Paths." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 62, no. 1 (September 2018): 1197–201. http://dx.doi.org/10.1177/1541931218621275.
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Healthcare practitioners today find themselves confronting a multitude of diverse and complex tasks while under time-sensitive conditions. This dynamic is particularly apparent in the operating room, where for each operation, doctors and nurses have to make sure each surgery condition is optimal to avoid surgery complications and the spread of infections. Checklists are a helpful tool to avoid glossing over these critical steps, but their current implementation is outdated and does not leverage human-centered technology. We propose a checklist design for operating rooms that is generated by an intelligent system and is interacted with through a voice interface. By removing this burden away from the nursing staff, routine safety procedures can be expedited, and practitioners can redirect their full attention to the operation at hand.
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McCann, Roger C., and P. V. R. Suryanarayana. "Horizontal Well Path Planning and Correction Using Optimization Techniques." Journal of Energy Resources Technology 123, no. 3 (May 11, 2001): 187–93. http://dx.doi.org/10.1115/1.1386390.
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We present a procedure that uses nonlinear optimization theory to plan complex, three-dimensional well paths and path corrections while drilling. The problem of hitting a 3-D target is posed as seeking a profile that optimizes some well-defined objective function (the optimality criterion) subject to equality and inequality constraints. The well path is idealized to contain a finite combination of turn and straight sections. Operational restrictions translate into inequality constraints, and target restrictions translate into equality constraints. Several optimality criteria may be chosen, and appropriate choices are discussed. In this work, we choose optimization with respect to user preferred parameters as the criterion. The resulting nonlinear optimization problem is solved using a sequential gradient-restoration algorithm (SGRA), with scaling and optimal step-size selection. The optimization problem formulation and the solution procedure are described. The procedure is robust, efficient, and clearly superior to trial-and-error heuristic techniques that are commonly used to plan well paths today. A computer program based on this technique has been developed and successfully used. Two examples are included to illustrate the procedure. It is concluded that nonlinear optimization is a powerful and versatile mathematical tool that can be used for planning better, optimal well paths, and can be extended to several other drilling and production problems.
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Leitão, C., R. M. Leal, D. M. Rodrigues, P. Vilaça, and A. Loureiro. "Material flow in Friction Stir Welding." Microscopy and Microanalysis 14, S3 (September 2008): 87–90. http://dx.doi.org/10.1017/s1431927608089472.
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Friction stir welding (FSW) is a solid-state joining technique initially developed for aluminium alloys. The heat generated by a rotating tool softens the material in the vicinity of the tool. The material undergoes intense plastic deformation following quite complex paths around the tool, depending on the tool geometry, process parameters and material to be welded. The comprehension of the material flow is essential to prevent voids and other internal defects which may form during welding. Several techniques have been used for tracking material flow during FSW such as metallography, the use of a marker material as a tracer or the flow visualization by FSW of dissimilar materials or even the X-ray and computer tomography. Some of these techniques are useless in the analysis of welds in homogenous materials or welds between materials of the same group. The aim of this investigation is tracking the material flow in FSW between 1mm thick sheets in aluminium alloys AA 5182-H111 and AA 6016-T4, currently used in automotive industry.
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Han, Guang Chao, and Bo Li. "Recent Development of Vibration-Assisted Abrasive Machining." Advanced Materials Research 328-330 (September 2011): 27–31. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.27.
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Vibration-assisted machining (VAM) combines small-amplitude vibration with different machining process to improve the process fabrication quality. It has been applied to a number of machining processes, such as turning, drilling, grinding and polishing. The emphasis on this literature is the vibration-assisted abrasive machining (VAAM), which involves with finishing and grinding processes where VAAM have been applied to hard metal, brittle material and complex geometries products like optical molds. This paper presents different vibrating units in VAAM from tool vibration to workpiece vibration, which also includes different vibrating paths from linear to ellipse. Typical hardware systems used to achieve these vibratory motions are described too.
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Skakoon, James G. "The Route That Forces Take." Mechanical Engineering 130, no. 09 (September 1, 2008): 39–42. http://dx.doi.org/10.1115/1.2008-sep-4.
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This article discusses that visualizing the load path in a design can uncover areas open to improvement. Planning the force transmission path during mechanical design is hardly dazzling engineering analysis, but explicitly doing so will improve your designs. By visualizing the transmission of forces, one can eliminate unnecessary parts, strengthen the design, and identify potential problems for further analysis or correction. Visualizing the path of transmitted forces for cables is pretty easy; forces follow the tension cables. But it is only slightly more complex with compression and shear involved. Although design is never a strictly linear progression, reviewing and refining the load path should be a formal part of the design process. Troubles with the load path in user-centered device design may become obvious with testing, but thinking about load paths as a human factor design issue can save time and effort. It is not a highly analytical design tool, but visualizing and refining load paths in structures and mechanisms is extraordinarily useful for designers, and it’s simple.
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Fung, L. S. K. S. K., X. Y. Y. Ding, and A. H. H. Dogru. "Unconstrained Voronoi Grids for Densely Spaced Complex Wells in Full-Field Reservoir Simulation." SPE Journal 19, no. 05 (January 30, 2014): 803–15. http://dx.doi.org/10.2118/163648-pa.
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Summary Accurate representation of near-well flow is an important subject matter in reservoir simulation. In today's field-scale reservoir simulation, cell-centered structured grids remain the predominant practice. Typically, well-inflow performance of the perforated cells is connected to the finite-volume solution by means of well indices that may not be well-defined when the wellbore intersects the finite-volume cells in a complex trajectory. Fine gridding is also required to resolve the flow dynamics in the near-well regions. Strong grid-orientation sensitivities can also contribute to the numerical errors and may require significant local grid refinement to alleviate. There are ongoing resesarch-and-development (R&D) efforts on applying unstructured grids to better represent the near-well flow in reservoir simulation, but their applications are mainly in single-well study or sector modeling with a few wells. Some of the reasons cited for this include (1) the lack of an effective, easy-to-use full-field complex well-gridding tool; (2) the lack of supporting unstructured workflow for full-cycle reservoir simulation; (3) the cost of unstructured-grid simulation; and (4) the availability of post-analysis and visualization tools for unstructured-grid simulation. The paper describes a novel method to automatically generate unstructured grids that conform to complex well paths in field-scale simulation. The method uses a multilevel approach to place cells optimally within the solution domain on the basis of the “regions of interests.” The wellbore geometry is honored by means of the construction of a near-well grid that is complemented with multilevel quad-tree (Fig. 1) refinements to achieve the desired resolution in grid transition zones. The method includes an algorithm to remove small cells and pinching cells on the basis of local grid quality measures and cell prioritization to honor well paths. The gridding process forms a component of a production-level reservoir-simulation workflow. The use of unstructured grid results in computational savings by placing cells where the resolution is needed. An in-house massively parallel simulator is used to run the unstructured-grid models. Simulation examples for full-field applications with hundreds of complex wells by use of both structured grids and unstructured grids will be used to compare results, accuracy, and performance of the gridding method for reservoir simulation.
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Chen, Haomin, Lee Loong Wong, and Stefan Adams. "SoftBV – a software tool for screening the materials genome of inorganic fast ion conductors." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 1 (January 19, 2019): 18–33. http://dx.doi.org/10.1107/s2052520618015718.
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The identification of materials for advanced energy-storage systems is still mostly based on experimental trial and error. Increasingly, computational tools are sought to accelerate materials discovery by computational predictions. Here are introduced a set of computationally inexpensive software tools that exploit the bond-valence-based empirical force field previously developed by the authors to enable high-throughput computational screening of experimental or simulated crystal-structure models of battery materials predicting a variety of properties of technological relevance, including a structure plausibility check, surface energies, an inventory of equilibrium and interstitial sites, the topology of ion-migration paths in between those sites, the respective migration barriers and the site-specific attempt frequencies. All of these can be predicted from CIF files of structure models at a minute fraction of the computational cost of density functional theory (DFT) simulations, and with the added advantage that all the relevant pathway segments are analysed instead of arbitrarily predetermined paths. The capabilities and limitations of the approach are evaluated for a wide range of ion-conducting solids. An integrated simple kinetic Monte Carlo simulation provides rough (but less reliable) predictions of the absolute conductivity at a given temperature. The automated adaptation of the force field to the composition and charge distribution in the simulated material allows for a high transferability of the force field within a wide range of Lewis acid–Lewis base-type ionic inorganic compounds as necessary for high-throughput screening. While the transferability and precision will not reach the same levels as in DFT simulations, the fact that the computational cost is several orders of magnitude lower allows the application of the approach not only to pre-screen databases of simple structure prototypes but also to structure models of complex disordered or amorphous phases, and provides a path to expand the analysis to charge transfer across interfaces that would be difficult to cover by ab initio methods.