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McLeay, T. E. "Unsupervised monitoring of machining processes." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/16556/.
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Machining processes, such as milling, drilling, turning and grinding, concern the removal of material from a workpiece using a cutting tool. These processes are sensitive to parameters such as cutting tool properties, workpiece materials, coolant application, machine selection, fixturing and cutting parameters. The focus of the work in this thesis is to devise a method to monitor the changing conditions of a machining process over time in order to detect faulty machining conditions and diagnose fault types and causes. A key aim of this thesis is to develop a monitoring regime that has minimal cost of implementation and upkeep in a production environment, therefore an unsupervised monitoring system which applies non-intrusive sensing hardware is proposed.
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Sharma, Chetan M. Eng Massachusetts Institute of Technology. "Automatic modeling of machining processes." Thesis, Massachusetts Institute of Technology, 2021. https://hdl.handle.net/1721.1/130833.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, February, 2021<br>Cataloged from the official PDF of thesis.<br>Includes bibliographical references (pages 47-48).<br>3 axis CNC milling is a ubiquitous manufacturing method in industry due to its versatility and precision. The fundamental parameters that dictate cutting performance ("speeds, feeds, and engagement") must be manually set by the machine programmer; proper operation therefore relies heavily on operator skill. In this thesis, an intelligent CNC controller is presented that uses low-cost sensors to fit an analytical model of cutting forces. The analytical nature of this model allows for favorable convergence characteristics and low computational costs. This is used to optimize cutting feeds with respect to process constraints for future movements; as more data is collected, the model continuously reinforced. This intelligent controller therefore abstracts out some of the complexities of machining and makes the process more approachable.<br>by Chetan Sharma.<br>M. Eng.<br>M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Su, Jiann-Cherng. "Residual stress modeling in machining processes." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14030.
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Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2007.<br>Committee Chair: Liang, Steven Y.; Committee Member: Garmestani, Hamid; Committee Member: Huang, Yong; Committee Member: Melkote, Shreyes N.; Committee Member: Neu, Richard W. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hameed, Saqib. "Electroplastic cutting influence in machining processes." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/460768.
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The thesis presented is performed with the aim of studying the effect of electropulses (EPs) in machining processes such as drilling and round turning processes for different materials. When the EPs of short duration are applied to metals undergoing plastic deformation, the deformation resistance decreases and plasticity increases at the same time. The influence of EPs on the plastic flow is called electroplastic effect. Chip formation during machining is greatly influenced by cutting speed, feed rates and tool geometry. Selecting properly these parameters for a particular machining operation is very important to achieve high machining efficiency.
It was found that EPs assisted cutting processes improve the machinability of materials based on the electroplastic effect. The influence of EPs in drilling process is studied by combining different feed rates, drill diameters and current densities in aluminium 7075 and steel 1045. Similarly, the effect of electropulsing has been observed for aluminium 6060 and steel S235 during turning process. The correlation between chip compression ratio , shear plane angle f , cutting speed, feed rates and current densities have been studied in EPs assisted processes. It has been observed that lower feed rates and subsequently, high current densities reduce the shear angle f and increase the chip compression ratio during drilling process. The specific cutting energy (SCE) is reduced upto 27% in aluminium 7075 and 17% in steel 1045 when drilling is assisted with EPs. However, the chip compression ratio decreases and shear plane angle f increases with the increase in cutting speed during turning of steel S235. In contrast, chip compression ratio increases and shear plane angle decreases with the increase in cutting speed while turning of aluminium 6060. The current density decreases with the increase in feed rates and increases with the increase in cutting speed in steel S235. However, current density has high values at higher feed rates and it decreases with the increase in cutting speed during turning of aluminium 6060. The SCE decreased with the increase in feed rates and depth of cut during electrically assisted turning of steel S235. But for aluminium 6060, the SCE increased whenthe cutting speed is increased.
The results elaborated that electrically assisted drilling process improves the material machinability by decreasing SCE in aluminium 7075 and steel 1045. The electrically assisted turning process seems to have influence in improving the machinability of steel S235 but for aluminium 6060, the plastic deformation tends to be increased by increasing the SCE during EPs assisted turning process.<br>La tesis presentada tiene como objetivo estudiar el efecto insitu de aplicar pulsos de corriente (EPs) a dos proceso de arranque de viruta, taladrado con taladro de pedestal y cilindrado en torno, todo ello aplicado a diferentes materiales. Cuando los EPs de corta duración se aplican a metales sometidos a deformación plástica, la resistencia a la deformación disminuye y la plasticidad aumenta al mismo tiempo. La influencia de los EPs en el flujo plástico se llama efecto electroplástico. La formación de virutas durante el mecanizado está muy influenciada por la velocidad de corte, las velocidades de alimentación y la geometría de la herramienta. La selección apropiada de estos parámetros para una operación de mecanizado particular es muy importante para lograr alta eficiencia de mecanizado. Se encontró que los procesos de corte asistido por EPs mejoran la maquinabilidad de materiales basado en el efecto electroplástico. La influencia de los EPs en el proceso de taladrado se estudia combinando diferentes velocidades de alimentación, diámetros de taladro y densidades de corriente en aluminio 7075 y acero 1045. De forma similar, el efecto de los electropulsos se ha observado para aluminio 6060 y acero S235 durante el proceso de torneado. La correlación entre la relación de compresión de viruta , el ángulo del plano de corte f, la velocidad de corte, las velocidades de alimentación y las densidades de corriente se han estudiado en los procesos asistidos por EPs. Se ha observado que las velocidades de alimentación más bajas y posteriormente, las altas densidades de corriente reducen el ángulo de corte f y aumentan la relación de compresión de virutas durante el proceso de taladrado. La energía de corte específica (SCE) se reduce hasta 27% en aluminio 7075 y 17% en acero 1045 cuando se asiste el taladrado con EPs. Sin embargo, la relación de compresión del chip disminuye y el ángulo del plano de corte f aumenta con el aumento de la velocidad de corte durante el torneado del acero S235. Por el contrario, la relación de compresión de la viruta aumenta y el ángulo del plano de corte disminuye con el aumento de la velocidad de corte en un torneado de aluminio 6060. La densidad de corriente disminuye con el aumento de las velocidades de avance y aumenta con el aumento de la velocidad de corte en acero S235. Sin embargo, la densidad de corriente tiene altos valores a mayores velocidades de alimentación y disminuye con el aumento de la velocidad de corte durante el torneado de aluminio 6060. El SCE disminuyó con el aumento en las velocidades de alimentación y la profundidad de corte durante el torneado asistido eléctricamente del acero S235. Pero para el aluminio 6060, el SCE aumentó cuando se incrementa la velocidad de corte. Los resultados muestran que el proceso de taladrado asistido eléctricamente mejora la maquinabilidad del material disminuyendo SCE en aluminio 7075 y acero 1045. También se observa una mejora en la maquinabilidad del acero S235 cuando es cilindrado en un torno, en cambio la SCE del aluminio 6060 disminuye empeorando la maquinabilidad, probablemente debido a la gran deformación plástica en la zona de corte que experimenta el material, lo que hace que amente la SCE durante el proceso de torneado asistido por EPs.
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Darling, Gordon. "Mathematical modelling of electrochemical machining processes." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/13565.
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Teltz, Richard W. "Open architecture control for intelligent machining systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0006/NQ42883.pdf.
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De, Sliva A. K. "Process developments in electrochemical arc machining." Thesis, University of Edinburgh, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383017.
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Otieno, Andrew Michael Wasonga. "Computer-aided analysis of metal machining." Thesis, University of Leeds, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251490.
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Bajalan, M. R. "Machining of steels with ceramic tools." Thesis, University of Warwick, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357239.
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Adebayo, Adeyinka. "Characterisation of integrated WAAM and machining processes." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8258.
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This research describes the process of manufacturing and machining of wire and arc additive manufactured (WAAM) thin wall structures on integrated and non¬integrated WAAM systems. The overall aim of this thesis is to obtain a better understanding of deposition and machining of WAAM wall parts through an integrated system. This research includes the study of the comparison of deposition of WAAM wall structures on different WAAM platforms, namely an Integrated SAM Edgetek grinding machine, an ABB robot and a Friction Stir Welding (FSW) machine. The result shows that WAAM is a robustly transferable technique that can be implemented across a variety of different platforms typically available in industry. For WAAM deposition, a rise in output repeatedly involves high welding travel speed that usually leads to an undesired humping effect. As part of the objectives of this thesis was to study the travel speed limit for humping. The findings from this research show that the travel speed limit falls within a certain region at which humping starts to occur. One of the objectives of this thesis was to study the effect of lubricants during sequential and non-sequential machining/deposition of the WAAM parts. Conventional fluid lubricants and solid lubricants were used. In addition, the effect of cleaning of deposited wall samples with acetone was also studied. A systematic study shows that a significant amount of solid lubricant contamination can be found in the deposited material. Furthermore, the results indicate that even cleaning of the wire and arc additive manufactured surfaces with acetone prior to the weld deposition can affect the microstructure of the deposited material.
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Bäckström, Mikael. "On monitoring and control of machining processes." Doctoral thesis, Luleå tekniska universitet, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16856.
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The thesis presents several aspects related to the industrial and academic activities associated with monitoring and control of the machining process and machine tools. A survey of the industrial situation identified some key factors for a successful implementation of monitoring and control techniques. Applicable, relatively simple, systems for cutting-process monitoring and adaptive control are available on the commercial market today but the degree of industrial utilisation of the technique is low because the systems are experienced as hard to operate and use, and are at the same time considered unreliable. In order to promote a higher degree of industrial utilisation more work has to be devoted raising the performance of the system solutions. An Integrated Supervisory Process Control (ISPC) concept is presented as an approach dealing with multi-purpose control requirements utilising the individual advantages of several sensors and modelling techniques. The ISPC system is supposed to operate as a conceptual integration of sensors, process models and different control modules. Two prototype systems, based on five-axis machining centres, for real-time control of the machining process are outlined. Different strategies for monitoring and control are developed, implemented and experimentally tried out, and the studies conducted demonstrate results that encourage further research work devoted to verification of the proposed control concept. The results obtained in the initial experiments utilising methods for process control and monitoring, such as double exponential smoothing technique (DES), multivariate monitoring applied to signal tracking and artificial neural networks applied to cutting torque control, reveal that the different techniques have potential to improve the performance of monitoring and control tasks, thus contributing to the creation of more sophisticated and reliable solutions in the ISPC concept.<br>Godkänd; 1999; 20061117 (haneit)
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Gupta, Deepak Prakash. "Development of an integrated model for process planning and parameter selection for machining processes." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5468.
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Thesis (Ph. D.)--West Virginia University, 2007.<br>Title from document title page. Document formatted into pages; contains v, 91 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 53-56).
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Atlar, Sibel. "Modelling Part Dynamicsin Machining Processes Considering Material Removal." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609154/index.pdf.
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Self-excited chatter vibration in machining is one of the most important limitations on utilizing the increasing productivity of modern machine tools. In order to predict stable depth of cuts at high cutting speeds, the stability lobe diagram for a spindle-tool holder-tool combination must be developed. The frequency response function (FRF) of the system must be known for analytical prediction of the stability lobe diagrams. When the flexibility of the workpiece is important, the workpiece itself should be included in the system model by considering the variation of its dynamics at different stages of the machining process.
In this thesis, an exact structural modification method is used to find the frequency response functions of the workpiece to be machined at every stage of the machining process. In order to obtain the system matrices and the modal parameters of the original structure, a commercial finite element program MSC. Marc©<br>is used. The frequency response functions of workpiece are calculated by using the computer program developed in this thesis, and are compared with the ones found by MSC. Marc©<br>. The stability lobe diagram of the system is obtained by combining the FRFs of the tool with those of the workpiece. The effects of the dynamic of the workpiece on the stability lobe diagrams are studied extensively by using the results of case studies presented in this thesis. In order to increase productivity, minimum chatter-free machining times are also calculated for different cases. For this purpose the effects of the different radial depth of cuts and different cutting strategies on the stability and the machining time are examined with various case studies.
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Tang, Yan. "INTEGRATED SERVOMECHANISM AND PROCESS CONTROL FOR MACHINING PROCESSES." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3298.
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In this research, the integration of the servomechanism control and process control for machining processes has been studied. As enabling strategies for next generation quality control, process monitoring and open architecture machine tools will be implemented on production floor. This trend brings a new method to implement control algorithm in machining processes. Instead of using separate modules for servomechanism control and process control individually, the integrated controller is proposed in this research to simultaneously achieve goals in servomechanism level and the process level. This research is motivated by the benefits brought by the integration of servomechanism control and process control. Firstly, the integration simplifies the control system design. Secondly, the integration promotes the adoption of process control on production floor. Thirdly, the integration facilitates portability between machine tools. Finally, the integration provides convenience for both the servomechanism and process simulation in virtual machine tool environment. The servomechanism control proposed in this research is based on error space approach. This approach is suitable for motion control for complex contour. When implement the integration of servomechanism control and process control, two kinds of processes may be encountered. One is the process whose model parameters can be aggregated with the servomechanism states and the tool path does not need real time offset. The other is the process which does not have direct relationship with the servomechanism states and tool path may need to be modified real time during machining. The integration strategies applied in error space are proposed for each case. Different integration strategies would propagate the process control goal into the motion control scheme such that the integrated control can simultaneously achieve goals of both the servomechanism and the process levels. Integrated force-contour-position control in turning is used as one example in which the process parameters can be aggregated with the servomechanism states. In this case, the process level aims to minimize cutting force variation while the servomechanism level is to achieve zero contour error. Both force variation and contour error can be represented by the servomechanism states. Then, the integrated control design is formulated as a linear quadratic regulator (LQR) problem in error space. Force variation and contour error are treated as part of performance index to be minimized in the LQR problem. On the other hand, the controller designed by LQR in error space can guarantee the asymptotic tracking stability of the servomechanism for complex contour. Therefore, the integrated controller can implement the process control and the servomechanism control simultaneously. Cutter deflection compensation for helical end milling processes is used as one example in which the process cannot be directly associated with the servomechanism states. Cutter deflection compensation requires real-time tool path offset to reduce the surface error due to cutter deflection. Therefore, real time interpolation is required to provide reference trajectory for the servomechanism controller. With the real time information about surface error, the servomechanism controller can not only implement motion control for contour requirement, but also compensation for the dimensional error caused by cutter deflection. In other words, the real time interpolator along with the servomechanism controller can achieve the goals of both the servomechanism and process level. In this study, the cutter deflection in helical end milling processes is analyzed first to illustrate the indirect relationship between cutter deflection and surface accuracy. Cutter deflection is examined for three kinds of surfaces including straight surface, circular surface, and curved surface. The simulation-based deflection analysis will be used to emulate measurement from sensors and update the real-time interpolator to offset tool path. The controller designed through pole placement in error space can guarantee the robust tracking performance of the updated reference trajectory combining both contour and tool path offset required for deflection compensation. A variety of cutting conditions are simulated to demonstrate the compensation results. In summary, the process control is integrated with the servomechanism control through either direct servomechanism controller design without tool path modification or servomechanism control with real time interpolation responding to process variation. Therefore, the process control can be implemented as a module within machine tools. Such integration will enhance the penetration of process control on production floor to increase machining productivity and product quality.<br>Ph.D.<br>Department of Mechanical, Materials and Aerospace Engineering<br>Engineering and Computer Science<br>Mechanical Engineering PhD
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Mestry, Sanket Dilip. "Software tool for analysis of manufacturing processes (STAMP)." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2661.
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Thesis (M.S.)--West Virginia University, 2002.<br>Title from document title page. Document formatted into pages; contains xii, 81 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 73-74).
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Guvener, L. Z. "Computer aided estimation of machining parameters for capacity planning." Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355427.
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Mahdi, Wathik Issa. "Tool contact stresses and chip formation in metal machining." Thesis, University of Bradford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254204.
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Osman, Zahid Muhammed Nafis. "Computer Numerical Controlled (CNC) machining for Rapid Manufacturing Processes." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16466.
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The trends of rapid manufacturing (RM) have influenced numerous developments of technologies mainly in additive processes. However, the material compatibility and accuracy problems of additive techniques have limited the ability to manufacture end-user products. More established manufacturing methods such as Computer Numerical Controlled (CNC) machining can be adapted for RM under some circumstances. The use of a 3-axis CNC milling machine with an indexing device increases tool accessibility and overcomes most of the process constraints. However, more work is required to enhance the application of CNC for RM, and this thesis focuses on the improvement of roughing and finishing operations and the integration of cutting tools in CNC machining to make it viable for RM applications. The purpose of this research is to further adapt CNC machining to rapid manufacturing, and it is believed that implementing the suggested approaches will speed up production, enhance part quality and make the process more suitable for RM. A feasible approach to improving roughing operations is investigated through the adoption of different cutting orientations. Simulation analyses are performed to manipulate the values of the orientations and to generate estimated cutting times. An orientations set with minimum machining time is selected to execute roughing processes. Further development is carried out to integrate different tool geometries; flat and ball nose end mill in the finishing processes. A surface classification method is formulated to assist the integration and to define the cutting regions. To realise a rapid machining system, the advancement of Computer Aided Manufacturing (CAM) is exploited. This allows CNC process planning to be handled through customised programming codes. The findings from simulation studies are supported by the machining experiment results. First, roughing through four independent orientations minimized the cutting time and prevents any susceptibility to tool failure. Secondly, the integration of end mill tools improves surface quality of the machined parts. Lastly, the process planning programs manage to control the simulation analyses and construct machining operations effectively.
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Brown, Neil. "Modification of the rotary machining process to improve surface form." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/32456.
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Planing and moulding operations carried out within the woodworking industry make extensive use of rotary machining. Cutter-marks are produced on the timber surface which are generally accepted as unavoidable. More noticeable surface defects may be produced by such factors as cutter-head imbalance, and until recently most research has concentrated on removing these defects. When a high quality finish is required, a further machining operation, such as sanding, is often required to remove cutter-marks. What is required, is a modified machining process which combines a surface closer to the ideal fixed knife finish, whilst retaining the flexibility, practicality and cost effectiveness of rotary machining.
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Chan, Tsz Lung. "Performance enhancement of machining process by an add-on online measurement system /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?IELM%202008%20CHAN.
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Lau, Pak Fai. "CNC machining accuracy enhancement by tool path compensation method /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?IEEM%202005%20LAU.
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Shore, Paul. "Machining of optical surfaces in brittle materials using an ultra-precision machine tool." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/3610.
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Investigations of machining optical surfaces into brittle materials using an ultra precision machine tool are presented. The newly developed ultra precision NION machine is evaluated to gain a good appreciation of its operating performance. The machining accuracy capability of this machine is established by careful measurement of its motion accuracy, thermal and dimensional stability and loop stiffness. Corroboration of these measurements are provided by assessment of surfaces which were produced in soft 'easily machined' metal materials. It was found that surfaces smooth to -1 nm Ra could be produced on the NION machine and with a form error of less than 100 nm P-V. The main source of figure error, approximately 80 nm, was found to be caused by the synchronous axial error motion of the workhead spindle. Other elements of the machine, including thermal effects, incurred less than 25 nm of additional figure error. Assessment of the diamond turning process for the producing optical surfaces made in a number of important optical materials, which are ostensibly brittle, were undertaken. Turning tests were carried out to establish the relative difficulty for machining optical surfaces in these materials and to define the most important parameters which affect the attained surface quality. Assessment of the produced surfaces was based on their roughness quality, surface morphology and residual stress condition. It was found that diamond tool edge quality degraded with total cut distance. Tool cut distance was found to be a major influence on achievable material removal rate before micro-fractures became present at the surface. Surface quality and residual stress condition were also greatly influenced by the overall tool cut distance. Diamond grinding trials were also carried out using the NION machine tool. These grinding trials were carried out using a mode of grinding which permits complex shape optical surfaces to be produced. Various grinding technologies were employed to establish the optimum methods. Selected grinding trials were carried out to establish the dominate parameters affecting the optical quality. Assessment of the machined surfaces was in regard of their surface roughness, residual stress and severity of sub-surface micro cracking. It was found that grinding wheel specification was a major influence on surface quality and sub-surface damage. The level of residual stress associated with 'ductile' mode grinding was not found to prohibit its application toward the direct manufacture of optical elements. Selection of grinding parameters which ensured the grain depth of cut, GDOC, parameter did not exceed the materials critical depth, dc, allowed glass surfaces to be ground to 1-2 nm Ra. These ground glass surfaces appeared free of any surface fractures. Sub-surface assessments did however reveal small levels of micro-fractures hidden below the surface. Discussion of both machining processes is provided. Available material removal rates for each process is given when cutting a number of important optical materials. Conclusions regarding the production of both Infrared and visible wavelength optics using the NION machine tool are provided. Recommendations for future work to improve both the understanding of the processes and the effectiveness of applying the processes are suggested.
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Boswell, Brian. "Use of air cooling and its effectiveness in dry machining processes." Curtin University of Technology, Dept. of Mechanical Engineering, 2008. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18869.
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Traditional liquid coolants used in metal machining are known to contain chemical carcinogens that could present serious health risks for machine operators and have inherent waste disposal concerns on the environment. In lessening these adverse effects, the manufacturing industry continually seeks to develop machining techniques incorporating liquid-less (dry) methods or environmentally benign coolants. Air-jet cooling is widely regarded as a viable alternative for liquid coolants in machining processes. This thesis proposes a novel air jet cooling arrangement, and assesses its thermal effectiveness and operational compatibility for specific requirements in metal cutting operation. For tests, steel rods were machined on a standard lathe workbench at selected cutting depth, feed and speed. Type 1040 steel, which is commonly used in automobile industry, was chosen as work piece material. Instead of traditional liquid coolant, a specially designed compressed air jet is used to dissipate heat generation in the cutting zone at the tool tip. The tool tip is presented orthogonally to the work piece to maintain conformity with relevant established cutting tool theories. A special air jet configuration based on a Ranque-Hilsch vortex tube was designed and developed for cooling the cutting zone and tool tip. The tool tip temperatures were measured by installing thermocouples at strategic locations on the tool piece and recorded on a data-logger for a range of cutting depths, feeds and speeds. The cutting power was measured with a power meter attached to the electrical power supply to the lathe. For comparison purposes, tests were also conducted with conventional single-nozzle air jets in place of the vortex-tube jets, using traditional liquid coolant and without any cooling applied to the tool tip.<br>A thermal vision camera was also deployed for selected tests to ascertain the temperature characteristics at the tool tip. The data was analysed to establish the thermal characteristics at the tool tip with vortex tube air jet, conventional air jet and no air jet cooling. The measured temperatures and cutting data were used to make assessments on cooling efficiency of jets used and surface finish quality of work piece. Estimates of tool life were made from the cutting theory to determine the effectiveness of the cooling systems used in the machining process. It is found that the proposed vortex tube based air jet cooling arrangement provides a highly efficient heat removal mechanism for metal cutting and delivers thermal cooling performance very much comparable to traditional liquid coolants without the inherent chemical exposure risks to machine operators and harmful impact on the environment. With the proposed air jet cooling, the tool life is very much unchanged and the surface finish quality of work piece shows no significant change while savings will realise though lesser dependency on liquid coolant requiring careful disposal and associated costs.
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Tsiakoumis, Vaios I. "An investigation into vibration assisted machining : application to surface grinding processes." Thesis, Liverpool John Moores University, 2011. http://researchonline.ljmu.ac.uk/6113/.
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The purpose of this study was to apply vibrations to the workpiece during surface grinding in order to improve the performance of the process. In addition to this, further necessary parameters were examined and analysed. A first step was to design the vibrating rig and after a number of different designs the most suitable model was selected for the conduction of the preliminary studies. However, a novel-improved system was designed and manufactured in order to undertake the full volume of experimental work. A number of simulations including stress and modal analysis were carried out and all the static and dynamic characteristics of the rigs were identified. Moreover, the exact dynamic behaviour of the rigs - including their natural frequencies - was established though real experiments. Sweep - sine and impact tests were employed in order to identify these dynamic parameters and the results were compared to those of simulation with the intention to detect the amount of error between these techniques. The rigs were vibrated at their resonant frequencies in order to achieve high values of amplitude with low voltage input. The static and dynamic characteristics of the grinding machine tool were identified. Similar methods such as sweep-sine test were employed in order to find the natural frequency of the machine tool's spindle unit. Static and dynamic stiffness of the machine tool's spindle unit as well as its compliance were identified. The preliminary studies showed an improvement in surface quality of the workpiece as well as a small reduction in cutting forces. This reduction was getting bigger with the increase of depth of cut. The main body of experimental work followed and showed that for 25 urn depths of cut, the vibration-assisted method could decrease up to 22.5 % the tangential forces. Furthermore, the effect of vibration was getting more noticeable at higher wheelspeeds and workspeeds. At those speeds the reduction in workpiece surface roughness reached 12.6%. Moreover, it was found that the application of vibration increased the material removal rate, reduced the cutting forces, increased the G-ratio and produced lower values of wheel wear compared to conventional grinding. Finally, an innovative closed-loop vibration control system was used for the process which could control the amplitude and the frequency of vibration in the actual grinding cycle. This I A Abstract system managed to control the applied values of vibration amplitude at resonant or near resonant frequencies. It was found that for higher depths of cut the closed-loop vibration control reduced the normal forces by 19% compared to open-loop control and 21 % compared to conventional grinding. Furthermore, the closed-loop control system performed better in terms of workpiece surface quality when grinding mild steel compared to conventional grinding and open-loop vibration control.
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Luo, Gaoyong. "Application of wavelet transforms to vibration analysis for wood machining processes." Thesis, Bucks New University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390816.
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Chao, C. L. "Investigations of the machining of glasses and other normally brittle materials in the ductile regime." Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302733.
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Repo, Jari. "Condition monitoring of machine tools and machining processes using internal sensor signals." Licentiate thesis, KTH, Machine and Process Technology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12872.
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<p>Condition monitoring of critical machine tool components and machining processes is a key factor to increase the availability of the machine tool and achieving a more robust machining process. Failures in the machining process and machine tool components may also have negative effects on the final produced part. Instabilities in machining processes also shortens the life time of the cutting edges and machine tool.</p><p>The condition monitoring system may utilise information from several sources to facilitate the detection of instabilities in the machining process. To avoid additional complexity to the machining system the use of internal sensors is considered. The focus in this thesis has been to investigate if information related to the machining process can be extracted directly from the internal sensors of the machine tool.</p><p>The main contibutions of this work is a further understanding of the direct response from both linear and angular position encoders due the variations in the machining process. The analysis of the response from unbalance testing of turn tables and two types of milling processes, i.e. disc-milling and slot-milling, is presented. It is shown that operational frequencies, such as cutter frequency and tooth-passing frequency, can be extracted from both active and inactive machine axes, but the response from an active machine axis involves a more complex analysis. Various methods for the analysis of the responses in time domain, frequency domain and phase space are presented.</p><br>QC 20100518
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Kurd, Michael Omar 1982. "The material and energy flow through the abrasive waterjet machining and recycling processes." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32766.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.<br>Includes bibliographical references (p. 109-111).<br>The purpose of this thesis was to investigate the material and energy flow through the abrasive waterjet machine and the WARD recycling machine. The goal was to track all of the material, water, abrasive, energy, air, and tooling through the different components of the machining and recycling processes. The material removal was found to be a function of length and part geometry, while all of the other variables were simply a function of time. The cutting speed determines the abrasive use, water use, and power use, and is varied based on the material, geometry, thickness and cut quality. The cutting speed was found to be linear with machineability--a measure of the material, almost linear with hardness--inversely related to thickness, somewhat inversely related to quality, and linear with power. Water was found to be the most abundant consumable, following by abrasive, together making up over 99% of the output waste. In the recycling process, roughly 60% of abrasive can be recycled after a single use, with the only significant consumable being power, used to dry the moist abrasive. Replacement tooling on both the abrasive waterjet and the WARD recycling unit were found to be negligible compared to the large amount of abrasive sludge produced every minute.<br>by Michael Omar Kurd.<br>S.B.
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Shafae, Mohammed Saeed Abuelmakarm. "Advancing the Utility of Manufacturing Data for Modeling, Monitoring, and Securing Machining Processes." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/96812.
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The growing adoption of smart manufacturing systems and its related technologies (e.g., embedded sensing, internet-of-things, cyber-physical systems, big data analytics, and cloud computing) is promising a paradigm shift in the manufacturing industry. Such systems enable extracting and exchanging actionable knowledge across the different entities of the manufacturing cyber-physical system and beyond. From a quality control perspective, this allows for more opportunities to realize proactive product design; real-time process monitoring, diagnosis, prognosis, and control; and better product quality characterization. However, a multitude of challenges are arising, with the growing adoption of smart manufacturing, including industrial data characterized by increasing volume, velocity, variety, and veracity, as well as the security of the manufacturing system in the presence of growing connectivity. Taking advantage of these emerging opportunities and tackling the upcoming challenges require creating novel quality control and data analytics methods, which not only push the boundaries of the current state-of-the-art research, but discover new ways to analyze the data and utilize it.
One of the key pillars of smart manufacturing systems is real-time automated process monitoring, diagnosis, and control methods for process/product anomalies. For machining applications, traditionally, deterioration in quality measures may occur due to a variety of assignable causes of variation such as poor cutting tool replacement decisions and inappropriate choice cutting parameters. Additionally, due to increased connectivity in modern manufacturing systems, process/product anomalies intentionally induced through malicious cyber-attacks -- aiming at degrading the process performance and/or the part quality -- is becoming a growing concern in the manufacturing industry. Current methods for detecting and diagnosing traditional causes of anomalies are primarily lab-based and require experts to perform initial set-ups and continual fine-tuning, reducing the applicability in industrial shop-floor applications. As for efforts accounting for process/product anomalies due cyber-attacks, these efforts are in early stages. Therefore, more foundational research is needed to develop a clear understanding of this new type of cyber-attacks and their effects on machining processes, to ensure smart manufacturing security both on the cyber and the physical levels.
With primary focus on machining processes, the overarching goal of this dissertation work is to explore new ways to expand the use and value of manufacturing data-driven methods for better applicability in industrial shop-floors and increased security of smart manufacturing systems. As a first step toward achieving this goal, the work in this dissertation focuses on adopting this goal in three distinct areas of interest: (1) Statistical Process Monitoring of Time-Between-Events Data (e.g., failure-time data); (2) Defending against Product-Oriented Cyber-Physical Attacks on Intelligent Machining Systems; and (3) Modeling Machining Process Data: Time Series vs. Spatial Point Cloud Data Structures.<br>PHD
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Li, Zhichao. "Modeling, analysis, and experimental investigations of grinding processes." Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/198.
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陳頌富 and Chung-fu Leslie Chan. "Machining process selection and sequencing under conditions of uncertainty." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31214927.
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Suyama, Daniel Iwao 1984. "Uma contribuição ao estudo do torneamento interno em aços endurecidos." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265935.
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Orientador: Anselmo Eduardo Diniz<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica<br>Made available in DSpace on 2018-08-25T12:18:47Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014<br>Resumo: A usinagem de materiais endurecidos, com dureza acima de 45 HRC, surge como alternativa à retificação na década de 70, com a disponibilidade comercial de ferramentas de Nitreto Cúbico de Boro (cBN). Porém, a baixa tenacidade deste tipo de ferramenta a torna muito sensível a avarias causadas por vibrações, que são críticas nas operações as quais a peça ou a ferramenta são suscetíveis a grandes deflexões. Este trabalho busca contribuir com o estudo de vibrações no torneamento interno de furos do aço AISI 4340 endurecido, em condições de acabamento. Foram testadas diferentes condições de usinagem, diferentes suportes (aço, metal duro e equipada com amortecedor de partículas) e foram avaliados o acabamento, os sinais de aceleração (vibração) da ferramenta e o desgaste dos insertos de cBN. Os resultados obtidos mostram que as vibrações podem assumir papel secundário no acabamento superficial, que a usinagem com ferramentas de geometria definida pode substituir a retificação em alguns casos e que a utilização de amortecedores passivos pode ser uma solução simples para a usinagem de furos mais longos<br>Abstract: The machining of hardened materials with hardness over 45 HRC, emerges as an alternative to grinding in the 70s, with the commercial availability of Cubic Boron Nitride (cBN) tools. However, the low toughness of this type of tool makes it very sensitive to damage caused by vibrations, which are critical in the operations which the part or tool are susceptible to large deflections. This work aims to contribute to the study of vibrations in internal turning of holes in hardened AISI 4340 steel in finishing conditions. Different machining conditions and different tool holders (steel, carbide and equipped with particle damper) were tested. The surface finish, the acceleration (vibration) signals and tool wear of cBN inserts were evaluated. The results show that the vibration can take a secondary role in the surface finish, the machining with defined geometry tools can replace grinding in some cases, and the use of passive dampers can be a simple solution for machining longer holes<br>Doutorado<br>Materiais e Processos de Fabricação<br>Doutor em Engenharia Mecânica
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Fang, Shiqi [Verfasser], and Dirk [Akademischer Betreuer] Bähre. "Defined structured cemented carbide tools for abrasive machining processes / Shiqi Fang ; Betreuer: Dirk Bähre." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2016. http://d-nb.info/1182989063/34.
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Saadat-Sarmadi, Mozafar. "Investigation of the machining processes of flexible fibrous materials for applications in industrial automation." Thesis, Durham University, 1992. http://etheses.dur.ac.uk/1124/.
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Roberts, Bryndan. "Integration of an electrical discharge machining module onto a reconfigurable machine tool." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/6182.
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Electrical Discharge Machining (EDM) is a non-contact manufacturing process in which material is removed from a metal workpiece by high frequency electrical pulses produced between an electrode and the workpiece. EDM machines are usually stand-alone devices, and are quite expensive. The objective of this research was to integrate an EDM machine and an existing reconfigurable CNC machine tool, using a modular approach, to enable conventional milling and EDM to be conducted in a co-ordinated fashion on the same machine tool.
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García, Tierno Marta. "Towards Sustainability Using Minimum Quantity Lubrication Technique and Nano-Cutting Fluids in Metal-Machining Processes." Thesis, KTH, Industriell produktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230581.
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Sustainable manufacturing is making products from processes which have minimal environmental impact, energy and resource efficient, economically viable and safe for consumers and society as whole. Achieving sustainability in manufacturing would mean infusing sustainability methods on product process and system level. On the process level, machining technology is one of the most widely extended processes in the industry. One way to attain sustainability in this technology is by adopting efficient management of Metal Working Fluids (MWF). In this purpose to reduce the amount of MWF starts Minimum Quantity Lubrication (MQL), where very small quantity of fluid is applied to the cutting zone with maximum precision. Moreover, addition of nanoparticles to these ´minimum quantity lubricants´ further enhances its tribological properties leading to higher reduction in friction and temperature in the machining process.The main objective of this thesis is to study the performance of cooling-lubricating fluids and these fluids modified with nanoparticles, how the use of this new lubricants improves the results obtained in material process technologies, particularly in turning. This project is being supported by the company LetsNano AB, providing the lubricants enhanced with nanoparticles and the funding, and Accu-Svenska AB, providing base oil and MQL technology.The experiments are carried out at Kungliga Tekniska Högskolan (KTH), at Institutionen för Industriell Produktion (IIP) laboratory. The turning process was tested with two different workipiece materials: hardened steel (Toolox® 44) provided by SSAB, and grey cast iron (Scania case study material). Two different tooling systems, due to the different materials. One provided by Mircona AB, and the other given directly by Scania, provided by Sandvik AB and Cermatec AB. The MQL system is a high-performance booster provided by Acuu-Svenska AB. The lubricant is a vegetable oil that will also be the base for the Nanofluids (NF). This Nanofluids and produced and developed by LetsNanoAB.The study revealed an encouraging potential of moving from conventional (dry) cooling techniques to the vegetable oil based MQL. Machining performance of MQL was encouraging as in most of the cases the systematic reduction in tool wear reveals a better machinability. The contribution of this work for Scania could help them to take the decision and move to more sustainable machining processes. To prove the potential of the nanotechnology in this kind of processes further study is needed, and it is going to be tested at IIP facilities in near future. The implementation of this technology brings more challenges that should considered a study of the hazards of the technology (emissions, fire and explosion, noise, skin…) necessary safety measures (cleaning, operator instruction, skin protection…) and modifications in the machine tools system beyond the process only. This could also be a next step in the further study of this research.<br>Hållbar tillverkning gör produkter från processer som har minimal miljöpåverkan, energi och resurseffektiv, ekonomiskt genomförbar och säker för konsumenterna och samhället som helhet. Att uppnå hållbarhet i tillverkningen skulle innebära infusion av hållbarhetsmetoder på produktprocess och systemnivå. På processnivå är bearbetningsteknologi en av de mest utbredda processerna inom branschen. Ett sätt att uppnå hållbarhet i denna teknik är genom att anta effektiv hantering av metallbearbetningsvätsko (MWF). I detta syfte för att minska mängden MWF startas Minimalsmörjning (MQL), där mycket liten mängd vätska appliceras på skärzonen med maximal precision. Dessutom ökar tillsatsen av nanopartiklar till dessa "minimala smörjmedel" ytterligare sina tribologiska egenskaper vilket leder till högre minskning av friktion och temperatur i bearbetningsprocessen.Huvudsyftet med denna avhandling är att studera prestanda av kylsmörjande vätskor och dessa vätskor modifierade med nanopartiklar, hur användningen av de här nya smörjmedlen förbättrar resultaten som erhållits i materialteknik, särskilt vid vridning. Projektet stöds av företaget LetsNano AB, vilket ger smörjmedlen förbättrad med nanopartiklar och finansieringen, och Accu-Svenska AB, som erbjuder basolja och MQL-teknik.Experimenten utförs vid Kungliga Tekniska Högskolan (KTH) vid Institutionen för Industriell Produktion (IIP). Vridprocessen testades med två olika material: Härdat stål (Toolox® 44) som SSAB levererade och grått gjutjärn (Scanias fallstudiematerial). Två olika verktygssystem, på grund av olika material. En som tillhandahålls av Mircona AB och den andra som ges direkt av Scania, tillhandahållen av Sandvik AB och Cermatec AB. MQL-systemet är en högpresterande booster som tillhandahålls av Acuu-Svenska AB. Smörjmedlet är en vegetabilisk olja som också kommer att vara basen för Nanofluiderna (NF). Dessa Nanofluider och produceras och utvecklas av LetsNanoAB.Studien avslöjade en uppmuntrande potential att flytta från konventionell (torr) kylningsteknik till den vegetabiliska oljebaserade MQL. Maskinens bearbetningsförmåga var uppmuntrande, eftersom i de flesta fallen den systematiska minskningen av verktygsslitaget visar bättre bearbetning. Arbetet med detta arbete för Scania kan hjälpa dem att fatta beslut och flytta till mer hållbara bearbetningsprocesser. För att bevisa nanoteknikens potential i denna typ av processer krävs ytterligare studier, och det kommer att bli testat vid IIP-anläggningar inom en snar framtid. Genomförandet av denna teknik ger fler utmaningar som bör övervägas en studie av farorna med tekniken (utsläpp, brand och explosion, buller, hud ...) nödvändiga säkerhetsåtgärder (rengöring, operatörsinstruktion, skydd mot huden ...) och modifikationer i verktygsmaskinerna system utöver processen bara. Detta kan också vara nästa steg i den fortsatta studien av denna forskning.
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Liou, Jiann-Haw. "Study of stress developments in axi-symmetric products fabricated by forging and machining /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9737869.
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Treurnicht, N. F. "High speed cutting and electric discharge machining as complementary processes in the die and mould industry." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53448.
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Thesis (MScEng) -- Stellenbosch University, 2003.<br>ENGLISH ABSTRACT: High Speed Cutting (HSC), specifically milling is a significant contemporary development in
machining. The Die and Mould industry is experiencing a difficult business climate. There
is competitive pressure for shorter lead times and lower prices. Companies worldwide, are
under financial pressure, to meet the challenges of a globalised business environment.
The conventional position of milling and Electric Discharge Machining (EDM / Erosion) is
discussed with the proposal to use HSC and EDM as complementary processes. Among
new developments the progress in computer infrastructure is prominent. There is also a
paradigm shift that should be made from experience based process planning to modern, up
to date knowledge based process planning. High Speed Cutting is now a mature process
capable of acceptable process security. The examples detailed include crankshaft-forging
tooling, injection moulding tooling and powder sintering tooling. A process chain is proposed
for the complementary HSC / EDM process with estimated illustrative time saving over the
conventional EDM dominated process. HSC will be the first process removing the bulk of
the material, finishing as far as possible and with EDM finally machining the features that will
be difficult or impossible with HSC.
To facilitate the use of the complementary processes a decision model to determine the
crossover point between HSC and EDM is proposed. The decision model is firstly
presented as a flow diagram to determine whether the task is a candidate for HSC only, EDM
only, or the complementary HSC / EDM process. The key parameters e.g tool H d ratio are
variables. This is in order that the flow diagram may be adapted to a specific machine tool
infrastructure and expertise level in a company. The second part is a HSC machining time
estimation model. The time is estimated per segment roughed, semi-finished, or finish
machined. The model is in an empirical form with constants that can be adapted to the
practices of a specific company. It is intended that the constants also be periodically revised
to reflect the development in HSC expertise that will occur during the use HSC in the
company. The model is practically evaluated with a case study, including the detail steps,
not included in the model. Conceptual guidelines are given for software implementation.
It is concluded that HSC and EDM are suitable complementary processes. It is a necessary
prerequisite to use pallets to avoid multiple set-ups. Complementary HSC and EDM is
especially appropriate for the gradual deployment and skill development for HSC. HSC and
complementary HSC / EDM is considered the opportunity for companies to make a major
breakthrough in lead time and operating expense if the necessary pallet/fixturing equipment,
CAx infrastructure and human capability is available.<br>AFRIKAANSE OPSOMMING: Hoe Spoed Masjinering (HSC), spesifiek frees is ‘n betekenisvolle ontwikkeling in
masjinering. Die Gereedskap en Gietvorm bedryf ervaar ‘n moelike besigheidsklimaat.
Daar is kompeterende druk vir korter lewertye en laer pryse. Maatskappye wereldwyd is
onder finansiele druk om in die geglobaliseerde besigheidsmilieu te presteer.
Die posisie van frees en Elektriese Ontladingsmasjinering (EDM / Vonkerosie) word
bespreek met die voorstel om HSC en EDM as komplementere prosesse te gebruik. Onder
die nuwe ontwikkelings is daar prominente vooruitgang in rekenaarinfrastruktuur. Daar is
ook ‘n paradigmaverskuiwing nodig van ondervinding gebaseerde na op datum kennis
gebaseerde proses beplanning. HSC is nou ‘n ontwikkelde proses met voldoende
prosessekerheid. Die voorbeelde sluit krukas smee gereedskap, inspuitgiet gereedskap, en
poeier-sinter persgereedskap in. ‘n Prosesketting word voorgestel vir die komplementere
HSC / EDM proses met ‘n beraamde illustratiewe tydbesparing oor die konvensionele EDM
gedomineerde proses. HSC sal die eerste proses wees wat die meerderheid van die
materiaal verwyder en oppervlaktes so ver as moontlik afwerk, met EDM wat die finale
afwerking doen en ook die masjinering wat vir moeilik haalbaar of onmoontlik is vir HSC.
Om die gebruik van die komplementere prosesse te fasiliteer, word ‘n beluitnemingsmodel vir
die oorgangspunt tussen HSC en EDM voorgestel. Dit word eerstens as vloeidiagram
gebruik om die taak te klassifiseer vir HSC alleen, EDM alleen of vir komplementere HSC en
EDM. Die sleutelparameters, bv die beitel 116 verhouding, is veranderlikes. Dit is sodat
die vloeidiagram aangepas kan word by ‘n spesifieke masjienvermoe en ‘n kundigheidsvlak
in ‘n maatskappy. Die tweede deel is ‘n HSC masjineringstyd model. Die tyd word beraam
per segment uitgerof, afgewerk, of finaal afgewerk. Die model is in empiriese vorm met
konstantes wat kan aangepas word by die praktyke van ‘n firma. Dit is die bedoeling dat die
konstantes periodiek aangepas word om die ontwikkeling te weerspieel wat in die
maatskappy plaasvind. Die model word prakties evalueer met ‘n gevallestudie, insluitend
die detailstappe, wat nie in die modelformulering ingesluit is nie. Konseptuele riglyne word
gegee vir programmatuur implementering.
Die gevolgtrekking word gemaak dat HSC en EDM geskikte komplementere prosesse is.
Dit is ‘n voorvereiste om pallette te gebruik om veelvuldige opstellings te vermy.
Komplementere HSC / EDM is veral toepaslik om HSC geleidelik in ‘n firma te ontplooi en
kundigheid te bou. Die HSC / EDM kombinasie word ook die geleentheid geag vir firmas om
‘n deurbraak te maak in lewertyd en bedryfsuitgawes as die nodige pallettoerusting, CAx
infrastruktuur en menslike vermoe beskikbaar is.
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Kim, Sangseop. "Determination of Wall Thickness and Height when Cutting Various Materials with Wire Electric Discharge Machining Processes." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/294.
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This thesis looks at the capabilities of cutting thin webs on Wire EDM machines that are difficult or impossible to machine using conventional methods. Covered is an investigation of how different material and web thickness affect the capability of machining thin-walled parts.
Five different metals are used for the test; Aluminum 6061 T6, Yellow Brass SS360, 420 Stainless Steel, D2 unheat-treated tool steel 25-30 RC, and D2 heat-treated tool steel 60-65 RC. The small parts were cut to a 6mm (0.2362 inch) height with six different wall thicknesses: 0.30mm (0.0118 inch), 0.25mm (0.0098 inch), 0.20mm (0.0078 inch), 0.15mm (0.0059 inch), 0.10mm (0.0039 inch), and 0.05mm (0.0020 inch). A Sodick AQ325L Wire EDM machine was utilized for testing.
The methods employed during the study include the following:
• Machine settings and offsets were limited to the default setting selected from the Sodick AQ325L database.
• Two different pre-test cuts were taken on the material to check for web bending during the cutting process.
• Hardness was tested for comparison of the web heights.
This thesis shows that bending increased as webs became thinner and that bending occurred toward the wire as the second side of the web was cut. Bending does affect the height of the web. Physical properties of materials also impacted the height of the web with the hardest material staying intact during the cutting process. This study shows that two factors, physical properties of materials and web thickness, significantly affect cutting results for thin web parts.
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Machado, Carlos Antonio Meyer. "Estudo comparativo de diferentes geometrias de corte em broca de metal duro com canal reto em ferro fundido cinzento." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264222.
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Orientador: Olivio Novaski<br>Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica<br>Made available in DSpace on 2018-08-18T21:16:59Z (GMT). No. of bitstreams: 1
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Previous issue date: 2011<br>Resumo: O objetivo deste trabalho é comparar o desempenho de duas diferentes geometrias de brocas de metal duro sem cobertura, com canal reto e refrigeração interna, na furação de ferro fundido cinzento. As geometrias avaliadas nos experimentos foram a geometria de ponta normalizada (normal) e uma geometria desenvolvida chamada de geometria de ponta esférica. A avaliação do desempenho foi feita com testes de vida realizados na linha de produção de blocos de motores, em que, além da vida, foram monitoradas a circularidade, a cilindricidade e o diâmetro dos furos. Os testes foram divididos em três partes, em que foi possível verificar a evolução do desgaste da aresta de corte da broca, da circularidade, da cilindricidade e dos diâmetros dos furos. Inicialmente foi utilizado como critério de fim de vida o tempo do processo original e posteriormente outro critério utilizado foi o desgaste da aresta principal. Os resultados obtidos permitiram concluir que a geometria de corte com melhor desempenho foi a geometria proposta, denominada esférica, que mostrou uma redução no custo na produção das peças estudadas, sendo possível esta implementação no processo de furação em ferro fundido cinzento em escala industrial. Na seqüência, utilizando a broca de geometria de ponta esférica foram feitos os mesmos monitoramentos para duas velocidades de corte maiores, sendo que os custos ficaram acima do resultado encontrado com os parâmetros de corte do processo original<br>Abstract: The aim of this study is to compare the performance of two different geometries of uncoated carbide drills, with straight flute and internal cooling, in drilling of gray cast iron. The geometries evaluated in the experiments were the standard tip geometry and a developed geometry called spherical tip geometry. The performance evaluation was done with life tests performed an engine blocks production line, for which, beyond tool life, measures were made for circularity, cylindricity and diameter of the holes. The tests were divided on three parts, where it was possible to check the wearing progress of the cutting edge of the drill, the circularity, cylindricity and diameter of the holes. Initially the original process time was used as end of life criteria and after the criterion of main edge wearing was used. The results showed that the cutting geometry with better performance was the one proposed, called spherical, which produced a reduction in the cost of manufactured parts, making possible the implementation of this process of drilling cast iron on an industrial scale. Subsequently, using the spherical tip drill geometry the same measures were made at two higher cutting speeds, and these last costs were higher than results found with the cutting parameters of the original process<br>Mestrado<br>Manufatura<br>Mestre em Engenharia Automobilistica
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Hsiao, Ya-Tsun. "In-process evaluation of tool wear effects on surface roughness variation in hard turning /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9904848.
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Gopalakrishnan, B. "Computer integrated machining parameter selection in a job shop using expert systems and algorithms." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53697.
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The research for this dissertation is focused on the selection of machining parameters for a job shop using expert systems and algorithms. The machining processes are analyzed in detail and rule based expert systems are developed for the analysis of process plans based on operation and work-material compatibility, the selection of machines, cutting tools, cutting fluids, and tool angles. Data base design is examined for this problem. Algorithms are developed to evaluate the selection of machines and cutting tools based on cost considerations. An algorithm for optimizing cutting conditions in turning operations has been developed. Data framework and evaluation procedures are developed for other machining operations involving different types of machines and tools.<br>Ph. D.
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Araujo, Geraldo Accetturi de. "Sistema de apoio à decisão na escolha de condições operacionais para processos de usinagem." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/3/3132/tde-23082010-104415/.
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O planejamento de processos é uma atividade essencial nas diversas etapas do ciclo de manufatura, em particular nas indústrias que produzem peças através de processos de usinagem. O uso de sistemas CAPP tem implicado em uma evolução nos sistemas de planejamento. A determinação da máquina, da ferramenta e das condições operacionais adequadas visando a otimização das diversas operações é fundamental para o sucesso do processo produtivo e da empresa, podendo ser melhorado pelo uso do CAPP. Estudam-se, assim, os fatores que influenciam esse tipo de processo, propondo-se um modelo de sistema protótipo para o seu planejamento, de forma a se ter no final uma especificação teórica da profundidade de corte, do avanço e da velocidade de corte, considerando aspectos como a usinabilidade do material da peça, os tempos de fabricação secundários e auxiliares, e a própria logística aplicada ao fluxo de peças no chão-de-fábrica através da definição quanto à máquina empregada ser ou não gargalo além de considerações sobre a disponibilidade de carga-máquina. Procurou-se elaborar um critério de otimização que considere não apenas o intervalo de máxima eficiência como proposto por vários autores, mas discuta a aplicação de seus limites e as restrições do sistema máquina-ferramenta-peça. Além do planejamento teórico o sistema possui um módulo de ensaios práticos visando refinar os valores teóricos da velocidade de corte adotada para garantir a sua perfeita aplicação com a máquina e a ferramenta adotados. A proposta do sistema é semi-generativa, unindo soluções algorítmicas e baseadas em conhecimento, com uma interface simples e amigável ao usuário.<br>Process planning is an essential activity in the several stages of the manufacturing cycle, particularly in industries which produce parts by means of machining processes. The use of CAPP systems has implied in a planning systems evolution. The determination of machine, tooling and suitable operational conditions looking at the optimization of the several operations is fundamental to the success of the productive process and of the enterprise, and can be improved by use of CAPP systems. It was studied the factors which influence this kind of process and it was proposed a prototype system model for this planning and for obtaining a theoretical specification of the depth of cut, feed and cutting speed, taking into consideration aspects like machinability of the part material, secondary and auxiliary manufacturing times, and the logistics applied to the flow of parts at the shop-floor through the definition of the used machine to be or not a production neck beyond considerations on the availability of machine capacity. It was proposed an optimization criterion which considers not only the maximum efficiency interval as quoted by many authors but also discuss the application of its limits and the restrictions of the system machine-tool-part. Besides the theoretical planning the system has a practical testing module intended to refine the theoretical values of the adopted cutting speed to guarantee its application to the defined machine and tooling. The system approach is semi-generative, with algorithmic and knowledge based solutions, with a simple and user-friendly interface.
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Faccio, Ian. "Investigações sobre o acabamento superficial de usinagens com altíssima velocidade de corte." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/3/3132/tde-23072003-135507/.
Full textAbstract:
Corpos de prova de ferro fundido foram usinados com altíssima velocidade de corte. Tiveram diversos parâmetros de sua rugosidade medida e os valores foram descritos em gráficos de rugosidade versus profundidade de corte. Pode-se verificar uma dependência entre estes valores, mas não o clássico aumento da rugosidade conforme o aumento da profundidade de corte. Realizou-se ainda a inspeção metalográfica dos corpos de prova na busca de mudanças de fase na estrutura ferro carbono que indiquem temperaturas elevadas no local, causadas pela alta velocidade de corte.<br>Cast iron test parts were high-speed machined. They had several roughness parameters measured and these values were plotted on roughness versus depth of cut charts. It could be noticed a relation between these values, but not the classical roughness increase due to the increase of depth of cut. Moreover, the metalographical analisys was performed for these test parts, in a search for phase changes on the carbon-iron structure which indicate high temperatures at the region, caused by the high cutting speed.
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Dória, Marcelo Antonio Teixeira. "Análise da influência da rigidez do sistema nos erros dimensionais e geométricos no processo de torneamento /." Ilha Solteira : [s.n.], 2005. http://hdl.handle.net/11449/94494.
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Orientador: Hidekasu Matsumoto<br>Banca: Amauri Hassui<br>Banca: Wyser José Yamakami<br>Resumo: Realizou-se um estudo da influência da rigidez estática do sistema Máquina-Ferramenta / Ferramenta de Corte / Dispositivo de Fixação / Peças (MFDP), na formação dos erros dimensionais e geométricos no processo de torneamento. Foi determinado a deflexão do sistema através de valores obtidos experimentalmente com a aplicação de forças estáticas em cinco pontos da peça de diâmetro 17 e 35 mm e comprimento 240 mm. Foi calculado a flexibilidade do carro porta ferramenta, da placa e do porta ferramenta, e a deflexão em todos os pontos de aplicação da força que variou de 49.05 N à 981 N. Usinou-se essas peças e estimou-se a força de corte atuante nas mesmas. Efetuou-se um comparativo entre os valores prático, teórico e usinado, com a peça fixa entre a placa e o ponto. Constatou-se que a rigidez do sistema, em especial a da peça tem grande influência na formação de erros das peças torneadas, e que com a equação que foi utilizada para os cálculos é possível prever os erros dimensionais e de forma de uma peça torneada.<br>Abstract: This study aimed to verify the influence of the Machine-Tool/ Cutting Tool/ Fixing Device and Parts rigidness on the causing of geographic and dimension errors in the process of tilting. It was determined the defluxion of the system through experimental values obtained by applying statistic forces in 5 points of the part. The shape has 17 and 35mm diameter and 240mm of length. It was calculated the flexibility of the tilting component tool, plate and the modifying tool, and the defluxion in all points of the applying forces varied from 49,05 N to 981981 N. The e was an estimative of the cutting power of these parts, and a comparison was made between practical, theoretical and factored values with the part fixed between place and point. It concluded that the rigidness of the system, in special in the part, has a great influence in the causing of errors of the tilted parts. The equation used for the calculation is possible for predicting dimensional errors and the shape of a tilted part.<br>Mestre
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Gilmore, Rhys. "An Evaluation of Ultrasonic Shot Peening and Abrasive Flow Machining As Surface Finishing Processes for Selective Laser Melted 316L." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1935.
Full textAbstract:
Additive Manufacturing, and specifically powder bed fusion processes, have advanced rapidly in recent years. Selective Laser Melting in particular has been adopted in a variety of industries from biomedical to aerospace because of its capability to produce complex components with numerous alloys, including stainless steels, nickel superalloys, and titanium alloys. Post-processing is required to treat or solve metallurgical issues such as porosity, residual stresses, and surface roughness. Because of the geometric complexity of SLM produced parts, the reduction of surface roughness with conventional processing has proven especially challenging. In this Thesis, two processes, abrasive flow machining and ultrasonic shot peening, are evaluated as surface finishing processes for selective laser melted 316L. Results of these experiments indicate that AFM can reliably polish as-built internal passages to 1 µm Ra or better but is unsuitable for passages with rapidly expanding or contracting cross-sections. AFM can also polish relatively small passages, but lattice components may prove too complex for effective processing. USP cannot achieve such low surface roughness, but it is a versatile process with multiple advantages. Exterior surfaces were consistently processed to 1.7 to 2.5 µm Ra. Interior surfaces experienced only partial processing and demonstrated high geometric dependence. USP significantly hardened the surface, but steel media hardened the surface better than ceramic media did. Both AFM and USP are recommended processes for the surface finishing of SLM manufactured parts. Good engineering judgement is necessary to determine when to use these processes and how to design for post-processing.
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Dória, Marcelo Antonio Teixeira [UNESP]. "Análise da influência da rigidez do sistema nos erros dimensionais e geométricos no processo de torneamento." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/94494.
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Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0
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doria_mat_me_ilha.pdf: 1141481 bytes, checksum: 2ce4bee4fea125f50133c730f3b951db (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Realizou-se um estudo da influência da rigidez estática do sistema Máquina-Ferramenta / Ferramenta de Corte / Dispositivo de Fixação / Peças (MFDP), na formação dos erros dimensionais e geométricos no processo de torneamento. Foi determinado a deflexão do sistema através de valores obtidos experimentalmente com a aplicação de forças estáticas em cinco pontos da peça de diâmetro 17 e 35 mm e comprimento 240 mm. Foi calculado a flexibilidade do carro porta ferramenta, da placa e do porta ferramenta, e a deflexão em todos os pontos de aplicação da força que variou de 49.05 N à 981 N. Usinou-se essas peças e estimou-se a força de corte atuante nas mesmas. Efetuou-se um comparativo entre os valores prático, teórico e usinado, com a peça fixa entre a placa e o ponto. Constatou-se que a rigidez do sistema, em especial a da peça tem grande influência na formação de erros das peças torneadas, e que com a equação que foi utilizada para os cálculos é possível prever os erros dimensionais e de forma de uma peça torneada.<br>This study aimed to verify the influence of the Machine-Tool/ Cutting Tool/ Fixing Device and Parts rigidness on the causing of geographic and dimension errors in the process of tilting. It was determined the defluxion of the system through experimental values obtained by applying statistic forces in 5 points of the part. The shape has 17 and 35mm diameter and 240mm of length. It was calculated the flexibility of the tilting component tool, plate and the modifying tool, and the defluxion in all points of the applying forces varied from 49,05 N to 981981 N. The e was an estimative of the cutting power of these parts, and a comparison was made between practical, theoretical and factored values with the part fixed between place and point. It concluded that the rigidness of the system, in special in the part, has a great influence in the causing of errors of the tilted parts. The equation used for the calculation is possible for predicting dimensional errors and the shape of a tilted part.
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Stefánsson, Trausti. "Application of Cryogenic Coolants in Machining Processes : State-of-the-art Literature Study and Experimental Work on Metal Matrix Composite." Thesis, KTH, Industriell produktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159516.
Full textAbstract:
Conventional cutting fluids are known for being expensive, polluting and a non-sustainable part of modern manufacturing processes. Global industrial trends are leaning towards environmental and health friendly technologies. Cryogenic cooling is an innovative and sustainable method, capable of replacing conventional oil-based cutting fluids under various conditions. The method has already proved to have a great potential in many different machining setups, performing equally or better than conventional cooling strategies in all criteria concerning machinability. Majority of research work published about cryogenic machining has revolved around turning operations most commonly in combination with steels, nickel-based alloys and titanium-based alloys. Other machining operations, e.g. milling and drilling, are less researched leaving the field with a great amount of unexplored areas. Although the technology has been developing for more than 60 years the general knowledge on the subject among machining specialists is relatively low. The room for improvements is large and further optimization is necessary before more generalization of the technique within the industry. In the first part of this work a comprehensive state-of-the-art literature study is presented, with the main focus on turning, milling and drilling operations. Parallel to the making of the essay, a new search system within published work about cryogenic technology was designed and developed to create a database of knowledge for Sandvik Coromant in future cryogenic research. The second part of the essay covers the experimental work where tests were performed in drilling of metal matrix composite under different cooling strategies. The results revealed an advantage in the favour of CO2 cryogenic cooling concerning precision and surface finish but an obvious need for further optimization of the process was evident as well.<br>Konventionella kylvätskor är kända för att vara dyra, förorenande och en icke-hållbar del av nutidens tillverkningsprocesser. Trenden inom industrin rör sig åt miljö- och hälsovänlig teknik. Kryogenisk kylning är en innovativ och hållbar metod som kan ersätta konventionella oljebaserade kylvätskor under olika förhållanden. Metoden har redan visat sig ha en stor potential i olika bearbetningsomständigheter, där den presterar lika bra eller bättre än konventionella kylningsstrategier för tillverkning. Största delen av forskningsarbetet som publicerats inom kryogen bearbetning har kretsat kring svarvning, oftast i stål, nickelbaserade legeringar och titanbaserade legeringar. Övrig bearbetning, t.ex. fräsning och borrning har mindre mängd publicerad forskning och lämnar ett stort outforskat område. Även om tekniken har utvecklats under mer än 60 år är den allmänna kunskapen inom ämnet bland bearbetningsspecialister relativt lågt. Potentialen för förbättringar är stor och ytterligare optimering behövs innan generell användning av tekniken kan ske inom industrin. I den första delen av detta arbete presenteras en allsidig “state-of-the-art“ litteraturstudie, med huvudfokus på svarvning, fräsning och borrning. Ett nytt söksystem för publicerade verk om kryogen bearbetning har även utvecklats och designats, detta för att skapa en databas med kunskap för framtida forskning inom ämnet hos Sandvik Coromant, Den andra delen av uppsatsen täcker det experimentella arbetet där som tester utfördes i borrning av metallmatriskomposit med olika kylningsstrategier. Resultaten visade en fördel för CO2 kryogenisk kylning vad gäller precision och ytfinhet, men ett behov av ytterligare optimering av processen var uppenbar.
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Steyn, Marisa. "Attributes and multi-criteria decision analysis in machine selection for process chains." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53308.
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Thesis (MEng)--University of Stellenbosch, 2003.<br>ENGLISH ABSTRACT: The purpose of this project is to find a means to evaluate a number of machines
to optimise a process chain. Firstly seven machine types were identified to be
included in the study. These machine types include: broach machines, EDM
machines, GNG lathes, engine lathes, drilling machines, milling machines and
grinders.
The information requirements for these machines in terms of attributes for three
areas were identified. Functionality, economical and reliability and availability
attributes were identified. These attributes were subsequently incorporated into a
MS-Access database to provide a database of machine information.
Several methods for comparing machines were studied and the decision then fell
on one existing method to be used for machine evaluation. A new method was
developed to use for evaluating machines. The existing method is the Analytic
Hierarchy Process, whereas the new method developed, is called the Quotient
Exponential Method.
These methods were implemented in the MS-Access database to enable the
user to evaluate machines by means of both methods.
The results indicate that these methods provide the correct answers according to
test values used. It should be noted that the decision methods should, however,
only serve as an aid towards an answer and do not necessarily provide the final
answer. The AHP process is very time-consuming for this project because of the
large number of criteria evaluated.<br>AFRIKAANSE OPSOMMING: Die doel van hierdie projek is om "n manier te vind om masjiene te evalueer om
sodoende "n proses-ketting te optimeer. Eerstens is besluit op die soorte
masjiene wat ingesluit gaan word in die projek. Sewe soorte masjiene is gekies
en sluit in: RNB draaibanke, masjiendraaibanke, boormasjiene, skuurders,
elektriese ontladings masjiene, veelvuldige punt snymasjiene en
rubeitelmasj iene.
Die inligting-vereistes van die sewe masjiene, in terme van hul attribute vir drie
areas, is vervolgens geïdentifiseer. Hierdie drie areas is funksionaliteit, koste,
asook beskikbaarheid en betroubaarheid. Hierdie attribute word in "n MS-Access
databasis gebruik om "n databasis van masjien-inligting te skep.
Verskeie metodes vir die vergelyking en evaluasie van masjiene is bestudeer en
daar is op een bestaande metode besluit vir die evaluering van "n aantal
masjiene. Daarbenewens is ook "n nuwe metode ontwikkel vir die evaluering van
masjiene. Die bestaande metode is die Analitiese Hiërargiese Proses, terwyl die
nuwe metode die Kwosiënt Eksponensiële Metode genoem word.
Altwee hierdie metodes is in MS-Access geïmplemeteer om die gebruiker in staat
te stelom masjiene met albei metodes te vergelyk.
Die resultate verkry toon aan dat die korrekte resultaat verkry word volgens die
toetsdata wat ingevoer is ten opsigte van die twee metodes. Dit moet in gedagte
gehou word dat hierdie metodes egter slegs as "n hulpmiddel tot besluitneming
gebruik behoort te word en nie noodwendig die finale antwoord lewer nie. AHP is
baie tydsaam gevind, aangesien die masjiene in die projek baie attribute bevat
het.
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UTTAM, SANGEET. "OPTIMAL TOLERANCE SYNTHESIS FOR PROCESS PLANNING WITH MACHINE SELECTION." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990648438.
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