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1
Liebman, Michael Kevin 1974. "Rotary-linear axes for high speed machining." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8218.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 353-358).
This thesis presents the design, analysis, fabrication, and control of a rotary-linear axis; this axis is a key subsystem for high speed, 5-axis machine tools intended for fabricating centimeter-scale parts. The rotary-linear axis is a cylinder driven independently in rotation and translation. This hybridization minimizes machine inertias and thereby maximizes accelerations allowing for the production of parts with complex surfaces rapidly and accurately. Such parts might include dental restorations, molds, dies, and turbine blades. The hybrid rotary and linear motion provides special challenges for precision actuation and sensing. Our prototype rotary-linear axis consists of a central shaft, 3/4 inch (1.91 cm) in diameter and 15 inches (38.10 cm) long, supported by two cylindrical air bearings. The axis has one inch (2.54 cm) of linear travel and unlimited rotary travel. Two frameless permanent magnet motors respectively provide up to 41 N continuous force and 0.45 N-m continuous torque. The rotary motor is composed of commercially available parts; the tubular linear motor is completely custom-built. The prototype axis achieves a linear acceleration of 3 g's and a rotary acceleration of 1,300 rad/s2. With higher power current amplifiers and reduced sensor inertia, we predict the axis could attain peak accelerations of 12 g's and 17,500 rad/s2 at low duty cycles. This thesis also examines several concepts for developing a precision rotary-linear sensor that can tolerate axial translation.
Our prototype rotary sensor uses two laser interferometers to measure the orientation of a slightly tilted mirror attached to the shaft. A third interferometer measures shaft translation. The rotary axis has a control bandwidth of 40 Hz; the linear axis has a bandwidth of 70 Hz. The rotary-linear axis has 2.5 nm rms linear positioning noise and 3.1 prad rms rotary positioning noise. This thesis presents one novel 5-axis machine topology which uses two rotary-linear axes. The first axis rotates and translates the part. The second axis carries the cutting tool and provides high speed spindle rotation as well as infeed along the axis of rotation. For use as a spindle, precision rotary sensing is not required, and a sensorless control scheme based on motor currents and voltages can be used.
by Michael Kevin Leibman.
Ph.D.
2
Bayless, Jacob D. (Jacob Daniel). "A high-speed hysteresis motor spindle for machining applications." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87955.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis. "February 2014."
Includes bibliographical references (pages 43).
An analysis of suitable drive technologies for use in a new high-speed machining spindle was performed to determine critical research areas. The focus is on a hysteresis motor topology using a solid, inherently-balanced D2 steel shaft. An analytical model of the motor is devised in order to make performance predictions and optimization, and an experimental apparatus is constructed in order to verify the predictions of the model and investigate speed limits. The model's limitations due to a still-incomplete understanding of the vector hysteresis properties of magnetic steels are noted, and a proposal for an experiment to resolve this limitation is presented. The model predicts that the motor performance is optimized for a very thin ring of hysteretic steel. The experimental apparatus used a solid rotor. It was run up to a speed of 11,000 RPM and torque-speed curves with various drive parameters are measured.
by Jacob D. Bayless.
S.M.
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Dagiloke, I. F. "Computer aided process parameter selection for high speed machining." Thesis, Liverpool John Moores University, 1995. http://researchonline.ljmu.ac.uk/4990/.
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Bezombes, Frédéric. "Fibre Bragg grating temperature sensors for high-speed machining applications." Thesis, Liverpool John Moores University, 2004. http://researchonline.ljmu.ac.uk/5630/.
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In high-speed grinding research, it is required to measure temperature within the workpiece. Present techniques are thermocouple based, and often suffer from excessive electrical noise on the signal. This thesis presents a number of novel and existing optical sensing devices that overcome this limitation and also, in some cases, offer greater performance. The optical sensors are fibre Bragg grating based and the optical techniques used to interrogate that sensor include DWDM, WDM, athermic grating, tuneable grating and coupler. Optical fibre devices are simpler to place in situ prior to the machining tests and they offer faster response and greater sensitivity than was previously possible. Results are presented from machining tests and the new devices are compared with each other and thermocouple based techniques. A method to relate internal measured temperature to machined surface temperature is also demonstrated in the context of high-speed machining.
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Chen, Ni. "Contouring control in high performance motion systems /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202005%20CHENN.
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Kishawy, Hossam Eldeen A. "Chip formation and surface integrity in high speed machining of hardened steel /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/NQ42858.pdf.
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Caulfield, F. Donald. "Electromechanical Actuator Development for Integrated Chatter Prediction on High Speed Machining Centers." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-04222002-234733/.
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Machine tool chatter imposes limitations on the productivity and quality of modern high speed machining (HSM) operations. It has been shown that chatter prediction and avoidance strategies can lead to increased machining productivity if certain modal characteristics of the machine are known. The objectives of this research are to design and demonstrate an electromechanical actuator (EMA) to easily and accurately identify these characteristics. Design specifications for this actuator reflect a wide range of machine tools and operating conditions. A simulation-based design strategy is employed, based on traditional electromechanical analysis, finite element analysis (FEA), and computer simulations to ensure performance meets the design specifications. A prototype EMA system is built to validate the analytical results and demonstrate its capabilities as part of an automated chatter prediction and avoidance system. The EMA is shown to generate the required modal characteristics, namely frequency response functions (FRFs) and stability lobe diagrams (SLDs) quickly, accurately, and with fewer technical skill requirements than other vibration testing methods. Experimental machining tests demonstrate that the EMA can be an effective component of an integrated chatter prediction and avoidance system.
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Pamali, Abhinand P. "Using Clothoidal Spirals to Generate Smooth Tool Paths for High Speed Machining." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-05212004-114758/.
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We present a new and innovative method to generate Contour Parallel tool paths using Clothoidal spirals for 2.5D pocket milling. The tool paths generated by the proposed method are more suitable for High Speed Machining compared to the traditional tool paths. Mechanical parts, such as those in Aerospace industry, Mold and Dies industry, etc require large volumes of milling operations. Modern High Speed CNC Machines are used in making of these parts. Although the High Speed CNC machines can provide very high spindle speed, due to various reasons, it has not been possible to use their High speed capabilities to their full extent. Two of the main reasons being, complex pocket geometry and complex tool path geometry. Most pockets are made up of sharp corners. In the traditional contour parallel pocket milling tool paths, as the cutting tool approaches these corners, they have to undergo a sudden change in directions and the acceleration of the tool has to be instantaneously decreased. Also, there is an instantaneous increase in the chip volume and the resultant forces acting on the cutting tool. In our proposed method we smooth these sharp corners of the traditional tool path by using Clothoidal spirals. The Clothoidal curves which have traditionally been used for Highways and Rail track design, have an unique property, according to which, the curvature of the Clothoidal spirals varies linearly with the length of the curve. By using these curves of uniformly varying curvature, we reduce the magnitude of the sudden direction changes that the cutting tool has to undergo at the sharp pocket corners. The cutting tool is subjected to lesser resultant forces and has a comparatively uniform acceleration. Machining time is also expected to be reduced by our proposed method.
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Modgil, Aditya. "Effects of high speed machining on surface topography of titanium alloy (Ti6Al4V)." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0002846.
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Wroblewski, Adam C. "Model Identification, Updating, and Validation of an Active Magnetic Bearing High-Speed Machining Spindle for Precision Machining Operation." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1318379242.
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Ekanayake, Risheeka Ayomi Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "An experimental study on high speed milling and a predictive force model." Awarded By:University of New South Wales. Mechanical & Manufacturing Engineering, 2010. http://handle.unsw.edu.au/1959.4/44821.
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This thesis presents the research work carried out in an experimental study on High Speed Milling and a predictive force model. The Oxley??s machining theory [36] that can be considered a purely theoretical approach, which has not yet been applied to the high speed milling process is used to model this process in order to predict the cutting forces. An experimental programme was carried out in order to study and understand the high speed milling process and to collect force data for machining of AISI 1020 plain carbon steel at speeds from 250 to 500m/min, feed rates 0.025 to 0.075mm/tooth and 0.5 and 0.8mm depths of cut, using three different tool configurations with different nose radii. The model developed by Young [5] using the Oxley??s machining theory, for conventional milling, was first applied to the high speed milling operation. The force predictions were satisfactory compared to the measured forces. Using this as the basis, a theoretical model was developed to predict the cutting forces in high speed milling. A smaller chip element was considered in applying the machining theory to satisfy the assumption of two dimensional deformation in the machining theory. Using the flow stress properties for plain carbon steels obtained by Oxley and his co-workers, the cutting force components: tangential, radial and vertical, were predicted with the new developed model for AISI 1020 steel for the same cutting conditions used in the experiment. The model was able to accurately predict the tangential force, while the other two components showed a good agreement with the experimental forces. Then the model was verified using two other materials namely, AISI 1045 plain carbon steel and AISI 4140 alloy steel. The alloy steel was used in both the states, virgin and hardened (heat treated) for the experiment. The comparison of predictions with experimental forces showed good results for these additional two materials. From the results obtained, it is concluded that the developed model can be used to predict the tangential cutting force accurately, while predicting the other force components with a favourable accuracy.
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Werschmidt, Carol Louise. "Creation and implementation of off-line programming for a high speed machining robot." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/16912.
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Akbar, Faraz. "An Investigation of Heat Partition in High-Speed Machining Using Uncoated and Coated Tools." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503049.
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Ascroft, Helen Louise. "Tribological evaluation of lubricant coatings in high speed and dry machining of aluminium alloys." Thesis, University of Birmingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694638.
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Ilyas, Ismet Priana. "Production of plastic injection moulding tools using selective laser sintering and high speed machining." Thesis, University of Leeds, 2007. http://etheses.whiterose.ac.uk/4048/.
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Global manufacturing trend and competition challenge every industry to seek new manufacturing methods to improve their business processes and speed up the product development cycle [Conolly, 2004a and Knights, 2001]. Among the candidates, layer manufacturing (LM) technologies appear to be a potential solution [Plam, 2002, and Grimm, 2004]. Recent LM technologies have led to a demanding application for developing production tools to manufacture parts, known as rapid tooling (RT). Selective laser sintering (SLS) is one of the leading LM systems available today in RT to manufacture injection mould (core/cavity) inserts [Kruth, 1998, Chua, 1999, Dormal, 1999, and Grenda, 2005]. However, the current capabilities of the SLS in producing metal parts have not yet fulfil the requirements of the injection mould inserts, especially in dimensional accuracy and surface finish quality [Francis, 2002 and Dalgamo, 2001 a]. The aim of this research is to use indirect SLS and high speed machining (HSM) in developing production-quality plastic injection moulding (core/cavity) inserts. The idea is that the indirect SLS process is utilised to build a near-net-shape inserts, while HSM is then utilised to finish the inserts to production specifications. Benchmark studies have been carried out to characterise the capabilities of both SLS and HSM with reference to the typical requirements of injection mould inserts. Utilising the study results, new developments of the mould inserts have been implemented on three major industrial case studies. Their performances have been evaluated and measured by comparing them with its respective original inserts. Furthermore, a set of design rules has been derived from best practices of the case studies, and have been validated by developing a new design for each case studies inserts. The results have demonstrated that the indirect SLS process has a capability III manufacturing a near-net shape of the insert which requires further related finishing to achieve final production specifications. The insert performances in some case studies have indicated significant improvements in process productivity and energy consumption as well as economic benefits to using the inserts. Regarding the significant considerations in realising the design, a recommendation on further strategic design rules and manufacturing process are highlighted so that the development of the insert using the selected approach can be more effective and efficient. Moreover, a utilisation of computer analysis software and further durability trial is also highlighted in order to predict and evaluate the optimum overall performance.
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Chen, Wuyi. "The machining of hardened steel using superhard CBN tooling and CBN tipped rotary cutting tools." Thesis, University of Birmingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342395.
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Mulyadi, Ismet. "Improving the performance of minimum quantity lubrication in high speed milling and environmental performance analysis." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/improving-the-performance-of-minimum-quantity-lubrication-in-high-speed-milling-and-environmental-performance-analysis(225a6b11-f4e6-44be-b7e5-3296f9cb87b9).html.
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Manufacturing by mechanical machining has historically benefited from the use of cutting fluid. Cutting fluids help to reduce temperature, friction, flush away chips, and hence prolong tool life and improve machining performance. However, uncontrolled use of cutting fluid raises concern in respect of cost and environmental burden. For these reasons, dry machining is used in conjunction with high speed machining to reduce cycle times and simultaneously deliver a greener process. However, for some workpiece materials full implementation of dry machining is not economically viable due to the absence of the essential cooling and lubricating functions delivered by cutting fluids. The most feasible bridging technology is minimum quantity lubrication (MQL) where a very small flow rate of coolant/lubricant is delivered to the cutting zones. In terms of machinability, the application of MQL is promising. However, most studies conducted on MQL focused on the feasibility of MQL application and show-casing the technical benefits. No studies had been identified in literature systematically investigating the relationship between cutting conditions and MQL with the goal of optimising the process. Moreover, the presumed environmental benefits of MQL have not been systematically assessed because Life Cycle Analysis (LCA) derived evaluation models do not explicitly model the impact of machining conditions such as feedrates, cutting velocities and depth of cut.The motivation for this PhD work was to select the optimum machining process variables for maximising effectiveness of MQL, to explore process improvements and to assess the environmental credentials of the process in relation to other forms of cutting environments. In this work, high speed, end milling tests on tool steel were undertaken and 1) Taguchi methods were used to optimise the process, 2) the sensitivity of tool wear to nozzle position was evaluated and 3) the environmental burden of dry, MQL and flood coolants were evaluated based on direct energy needs and process outputs. A fluid soaking device was used to assess the amount of fluid collected or presumed to be delivered to the cutting zone for different nozzle orientations.The Taguchi process optimisation suggested that in HSM the size effect, brought about by a low chip thickness, should be considered in the search for an optimum process window for HSM. A significant and novel finding of this PhD was the dominance of MQL nozzle positioning. The study clearly showed that when machining hardened steel at a high cutting speed and RPM the tool life could be significantly increased by 50% by adjusting the position of the nozzle toward the rake face in relation to the end-milled face. The work opens up new science and provides recommendations as to where to align the nozzle when end milling tool steel at high cutting speeds. The fluid trapping and the blade-wiping angle are key parameters that influenced the effective delivery of MQL when high spindle revolutions per minute are used. These results from the fluid soaking device were found to correlate strongly with observed machining performance evaluations.In terms of modelling, the PhD developed an improved and more generic direct energy model that can be used to determine the environmental burden for direct electrical energy requirements and the energy embodied in other process material outputs. This model addresses the system boundary and activity that within the control of the manufacturing plant. The model was used to evaluate the environmental performance of dry, flood and MQL fluids. The impact of these results and models in optimising environmental performance was also illustrated.The work in this PhD is important to industry in that it contributes to the optimisation of MQL and gives an assessment of the environmental impact. The PhD developed new and significantly important machining science in the positioning of nozzles in MQL machining at higher speeds.
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Machado, Carla Maria Moreira. "Empirical models for quantification of machining damage in composite materials." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/9058.
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Dissertação para obtenção do Grau de Doutor em
Engenharia MecânicaThe tremendous growth which occurs at a global level of demand and use of composite materials brings with the need to develop new manufacturing tools and methodologies. One of the major uses of such materials, in particular plastics reinforced with carbon fibres, is their application in structural components for the aircraft industry with low weight and high stiffness. These components are produced in near-final form but the so-called secondary processes such as machining are often unavoidable. In this type of industry, drilling is the most frequent operation due to the need to obtain holes for riveting and fastening bolt assembly of structures. However, the problems arising from drilling, particularly the damage caused during the operation, may lead to rejection of components because it is an origin of lack of resistance. The delamination is the most important damage, as it causes a decrease of the mechanical properties of the components of an assembly and, irrefutably, a reduction of its reliability in use. It can also raise problems with regard to the tolerances of the assemblies. Moreover, the high speed machining is increasingly recognized to be a manufacturing technology that promotes productivity by reducing production times. However, the investigation whose focus is in high speed drilling is quite limited, and few studies on this subject have been found in the literature review. Thus, this thesis aims to investigate the effects of process variables in high speed drilling on the damage produced. The empirical models that relate the delamination damage, the thrust force and the torque with the process parameters were established using Response Surface Methodology. The process parameters considered as input factors were the spindle speed, the feed per tooth, the tool diameter and the workpiece thickness. A new method for fixing the workpiece was developed and tested. The results proved to be very promising since in the same cutting conditions and with this new methodology, it was observed a significant reduction of the delamination damage. Finally, it has been found that is possible to use high speed drilling, using conventional twist drills, to produce holes with good quality, minimizing the damage.
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Andersson, Nils-Eric. "Structure and properties of thick plate and near surface properties after high speed machining af AA7010 /." Linköping : Univ, 2003. http://www.bibl.liu.se/liupubl/disp/disp2003/tek822s.pdf.
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Baharudin, B. T. Hang Tuah. "Experimental investigation of high speed micro machining of H13 tool steel and titanium alloy 6-4." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494133.
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High-accuracy miniaturized components are increasingly in demand for various industries such as aerospace, biomedical, electronics, environmental, communication and automotive, and this coupled with new developments of High Speed Machining (HSM) has led to the emergence of a strong and viable technology in High Speed Micro Machining. This technology is very important in bridging the macro-domain and the nano- and micro- domains for making functional miniaturized components. High speed Micro Machining is a specific technology where high spindle speeds, high performances cutting tools and high accuracy control systems are used. The understanding of this technology is still not well established and theories are still under development. A major implication of the High Speed Micro Machining process is the relatively high machining forces with respect to the cutting tool's size, which often cause low process reliability and high costs, due to frequent tool failures and short tool life. The aim of this investigation is to contribute towards a fundamental understanding of the effects of increased spindle speed in High Speed Micro Machining.
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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.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.
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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Blue, Michael Dewayne. "Development of a Non-contacting Capacitive Displacement Sensor for Integrated Chatter Prediction on High Speed Machining Centers." NCSU, 2003. http://www.lib.ncsu.edu/theses/available/etd-06052003-162301/.
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Chatter is an unstable forced vibration of the cutting tool during machining processes that can limit the productivity of high-speed machining. Chatter increases tool and machine wear rates, reduces tolerances, degrades surface finish, and can result in tool breakage. For these reasons, its avoidance is critical. Researchers at N.C. State University are focusing on the development of technologies to detect and avoid this dynamic instability. The primary objective of this project is to develop accurate, high bandwidth, low cost capacitive displacement sensors for use with a prototype electromechanically actuated chatter prediction device. These application-specific sensors are required to have at least 1.0 m resolution, 1.0 kHz bandwidth, and linearity over the desired measurement ranges. These sensors must output analog DC voltages proportional to the vertical and horizontal displacements of a specifically engineered machine tool. A simulation-based design process is utilized to optimize the mechanical and electrical aspects of these capacitive probes, the electrical circuits, and the mechanical mounting hardware. Performance and stability are simulated using MATLAB® and SPICE® modeling software and are validated experimentally using static and dynamic test rigs.
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Schuster, Joachim. "A CAD/CAM concept for high speed cutting compatible rough machining in die, mould and pattern manufacturing." Thesis, De Montfort University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685932.
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Enemuoh, Emmanuel Ugochukwu. "Smart drilling of advanced fiber reinforced composite materials /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9998482.
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Bonney, John. "High-speed machining of nickel-base, Inconel 718, alloy with ceramic and coated carbide cutting tools using conventional and high-pressure coolant supplies." Thesis, London South Bank University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410701.
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The first part of this study involve an evaluation of the performance of recently developed nano-grain size ceramic tool materials when machining nickel base, Inconel 718, with conventional coolant flow in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition. The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. It is also evident that chemical compositions of the tool materials played significant role in their failure. The alumina base ceramics performed better than the silicon nitride base ceramics. Severe abrasion wear was observed on both rake and flank faces of the cutting tools while cutting forces increased with increasing cutting speed when machining with the silicon nitride base nano-ceramic tools. This is probably due to the lower superplastic flow temperature of the nitride base nano-ceramics. The second part of this study involve turning of Inconel 718 with commercially available ceramic and PVD coated carbide tools with conventional and high-pressure coolant supplies at cutting speeds up to 300 and 60 m min" respectively. Increasing the coolant pressure results in shorter tool life when machining Inconel 718 with ceramic tools, suggesting that the high-pressure coolant supply reduces temperature at the cutting zone below a critical level where ceramic tools can perform satisfactorily. The inadequate fracture toughness of ceramic tools makes them more susceptible to failure by mechanical action such as notching at the depth of cut line and premature fracture. The notch wear rate increases with higher coolant supply pressure due to significant erosion of the tool material by the high-pressure coolant jet. Machining Inconel 718 with a triple PVD coated (TiCNI AI20iTiN) carbide tool at speeds up to 60 mlmin using conventional and various high coolant pressures, up to 203 bar was found to be encouraging. The test results show that acceptable surface finish and improved tool life can be achieved when machining Inconel 718 with high coolant pressures. Compared to conventional coolant supplies, tool life improved as much as 7 folds when machining at 203 bar coolant pressure at high speed conditions. Tool life generally increased with increasing coolant supply pressure due to the ability of the high-pressure coolant to lift the chip and gain access closer to the cutting interface. Chip breakability during machining is dependent on the depth of cut, feed rate and cutting speed employed as well as on the coolant pressure employed. Machining Inconel 718 with lower coolant pressures did not produce chip segmentation. Tool wear increased gradually with prolong machining with high coolant pressures. Nose wear was the dominating tool failure mode when machining with coated carbide tools due probably to a reduction in the chip-tool and tool-workpiece contact length/area. SEM micrographs of the machined surfaces show that micro-pits are the main damage to the machined surfaces. Microhardness analysis show evidence of hardening of the top machined surfaces. In most cases the microhardness readings tend to approach the hardness of the base material at 0.25 mm under rough and 0.2 mm under finish machining below the machined surface. This is due to the austenitic structure of Inconel 718 which promote work hardening when machining as a result of the high temperature generated at the cutting interfaces. The hardening effect decreased under finishing conditions and with increasing coolant pressures up to 203 bar as the coolant gain access closer to the cutting interfaces, thus minimising the cutting interface temperature. Analysis of the microstructure shows that severe plastic deformation occurred when machining with conventional coolant supply than with highpressure coolant supplies. There was also mild plastic deformation under finish machining. Surface damage or phase transformation was absent when machining Inconel 718 under highpressure coolant supplies. Generally the surface integrity of the finish machined surface is in accordance with CME 5043.
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El-Bialy, B. H. M. "A metallurgical and machining study of the behaviour of ion plated titanium nitride coated high speed steel cutting tools." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372142.
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VINJAMURI, REMA. "SOFTWARE PORTING FOR THE BEARCAT III ROBOT AND HIGH SPEED MACHINING IN ROBOTICS, AN INTRODUCTION AND ITS COST ANALYSIS." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1092842913.
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Fahad, Muhammad. "A heat partition investigation of multilayer coated carbide tools for high speed machining through experimental studies and finite element modelling." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/a-heat-partition-investigation-of-multilayer-coated-carbide-tools-for-high-speed-machining-through-experimental-studies-and-finite-element-modelling(dfa40f00-df30-403f-80ae-7533b41bedbd).html.
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High Speed Machining (HSM) is associated with higher cutting velocities and table feedrates and higher material removal rate, lower cutting forces in contrast to conventional machining. HSM can be undertaken dry or near dry and hence it is considered as environmentally friendly machining in relation to the use of cutting fluids. A key challenge in HSM is that, the thermal loads generated during the cutting process can be a major driver of thermally activated wear mechanism and hence affect machining performance. The ability of cutting tools to act as thermal barrier can be a highly desirable property for dry and HSM. Recently, research work has been conducted on laboratory based coated cutting tools to model and understand the fraction of heat that enters the cutting tool. These studies have shown the potential for TiN and TiAlN coated tools in reducing heat partition to the cutting tool when compared to uncoated tools. This PhD extended this work to modelling and characterising the heat partition for new generation commercial coated cutting tools considering tools from major insert manufactures. For this study commercial coated carbide tools were classified into two groups. In one group were coatings uniformly applied on both rake and flank faces of the insert (SERIES). The second group were tools that had different top coats for the rake and flank faces (Functionally Graded). This concept of functional grading is used to tailor the coating selection to the conditions that exist on a tool face. Moreover, the issue of restricted chip contact was modelled and clarified in terms of its impact on heat partition. This chip breaker design is of particular importance to inserts used for machining ductile materials. Thus the PhD has applied research methods to industrial cutting tools and helped elucidate the important aspects relating to the design, layout and selection of multilayer coatings. The heat partition was quantified by using a combined Finite Element (FE) and experimental approach. This methodology was applied by taking into consideration the appropriate friction phenomena during HSM i.e. sticking and sliding. A restricted contact length with groove profile geometry was considered for the application of heat load in the FE model. Orthogonal and external turning of AISI/SAE 4140 medium carbon alloy steel was conducted over a wide range of cutting speeds. An infrared thermal imaging camera was used to measure cutting temperatures. The results show that the layout of the coating can significantly affect the heat distribution into the cutting tool, specifically; the top coat can alter the friction conditions between the tool-chip contact. The distribution of heat (heat partition) into the cutting tool insert with the thickest layer of Al2O3 as a top coating is the lowest in the entire range of cutting speeds tested i.e. 10.5% at lower cutting speed and reduced to 3.4% at highest cutting speed. Investigations were also conducted to quantify the contribution of heat from the primary and secondary deformation zones using a combination of finite element modelling, analytical modelling and experimental data. The results deduced that the primary deformation zone heat source contributes 9.1% (on average) to the heat partition into the cutting tool. The contribution of the Thesis should be of interest to those who design, manufacture and coat cutting tools. It defines heat partition values for commercial coated carbide tools, assesses the requirements for multilayer design of thermally insulating cutting tools, the selection of coating top layer coats and the role of contact phenomenon on heat partition in dry and HSM of steels.
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Jílek, Bohumil. "Výroba vstřikovací formy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228550.
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This thesis is focused on a production of injection molds. It contains some analyses of the various parts of the injection molds, a description of their functions and the possibility of structural design. A summary of existing technologies for the production of these molds, their advantages and disadvantages is included. This thesis deals with design of the component parts for injection of plastics, strategy of machining and a simulation of machining.
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Tropp, Pavel. "Vysokorychlostní obrábění ložisek z materiálu 100Cr6." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231982.
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This Master's thesis deals with the issue of high-speed turning of the 100Cr6 material. The aim is to identify and experimentally validate an innovative production process for a particular component. The thesis includes theoretical basis of high-speed machining, analysis of the current state of the manufacturing process, innovation design and experimental verification. At the end of the thesis, parameters of the machined surfaces of specimens are evaluated.
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Sudo, Tadeu Tomio. "Uma contribuição ao estudo do torneamento com alta velocidade." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-15032016-134826/.
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O material, metálico ferro fundido cinzento, é muito utilizado industrialmente, principalmente na área automobilística. Usinagem com alta velocidade tem sido uma tendência atual para aumentar a produtividade, com a possibilidade de se ober ótima qualidade superficial, possivelmente eliminando processos subseqüentes. Aliado à questão de qualidade ambiental, as operações de usinagem têm-se voltado para usinagem a seco ou com mínima quantidade de lubrificante (MQL - minimal quantity of lubricant). Este trabalho estuda o torneamento com alta velocdidade de ferro fundido cinzento GG25 através de usinagem a seco e com MQL. Utiliza-se, em operação de faceamento, ferramenta de cerâmica mista (Al2O3+ TiC) e metal duro com cobertura (TiCN/Al2O3/TiN), usando velocidades de corte muito acima dos valores tradicionais. Comparativamente o desgaste é significativamente menor na cerâmica. O tipo de desgaste predominante é o desgaste de flanco. Os principais mecanismos de desgaste encontrados são abrasão mecânica e delaminação. O aumento do avanço diminui o desgaste de flanco. Existe uma razão entre a vazão de óleo e a vazão de ar na lubrificação MQL que viabiliza sua aplicacão com relação ao desgaste de flanco. Em todas as condições testadas, o sistema MQL mostra ser capaz de reduzir a rugosidade superficial Ra.The gray cast iron material is very used industrially, mainly in the automotive industry. High speed machining is the current tendency to increase the productivity, with the possibility of obtaining good surface quality, possibly eliminating subsequent operations. Due to regulations on the subject of environrnental quality, the machining operations have been turned to dry machining or minimal quantity of lubricant (MQL). This work studies the turning process at high speed of gray cast iron GG25 with dry machining and MQL techniques. The operation uses face turning with coated carbide (TiCN/Al2O3/TiN) and mixed alumina ceramic (Al203+ TiC) with cutting speeds much higher than the traditional recommended values. Comparatively, the wear is significantly smaller in the mixed alumina ceramic tools. The predominant type of wear is the flank wear. The main wear mechanisms are mechanical abrasion and delamination. The increase of feed values shows some reduction on the flank wear. It seems to exist an ideal ratio of oil to air in the MQL system, which makes possible its application for reducing flank wear on the tools. In all conditions tested, the MQL system shows to be able to reduce surface roughness (Ra).
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Šenkýř, Pavel. "Trendy vývoje obráběcích strojů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228222.
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This diploma thesis deals with trends of the development of machine tools, and focuses on technologies and machine tools for manufacturing of pressing dies and on manufacturing of cavity of moulds. First, the existing state in the field of these technologies is described and defined, and subsequently, the dissertation concentrates on modern conceptions of this manufacturing.
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Grandguillaume, Laureen. "Execution adaptative de trajectoire 5 axes sur structures poly-articulées." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN059/document.
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L’usinage 5 axes à grande vitesse est de plus en plus utilisé dans l’industrie pour réaliser des pièces de géométrie complexe à forte valeur ajoutée avec pour contrainte de respecter la qualité géométrique tout en maximisant la productivité. Dans ce contexte, la FAO et plus particulièrement la génération des trajectoires d’usinage jouent un rôle prépondérant. Ces travaux proposent de définir des trajectoires en fonction de la pièce à réaliser mais aussi de la structure poly articulée et de ses performances cinématiques. La grande diversité des structures en termes d’architecture et de cinématique impose une méthode de calcul générique facilitant la définition de trajectoires adaptées pour leur suivi. L’état de l’art des travaux réalisé dans les domaines de l’usinage et de la robotique pour répondre à cette problématique conduit à utiliser des polytopes de manipulabilité cinématique pour modéliser les contraintes cinématiques. L’analyse de ces polytopes et de la géométrie de la pièce à usiner permet de générer des trajectoires avec une vitesse outil/pièce maîtrisée et un temps de parcours réduit dans le cas de l’usinage 5 axes positionné et de l’usinage 5 axes continu. Ce formalisme met en avant les fortes dépendances entre les différents paramètres de la stratégie d’usinage (positionnement de la pièce, direction d’avance et orientation de l’outil) et permet de privilégier certaines combinaisons de ces paramètres pour maîtriser la vitesse d’exécution de la trajectoire5 axes high speed milling is increasingly used for manufacturing high addedvalue parts with complex forms in order to respect surface quality while maximizing productivity. In this context, CAM and more specifically toolpath computations play a major part. This work proposes to define toolpath depending on the workpiece but also onkinematical capacities of the polyarticulated structure.The large variety of structure in terms of architecture and kinematic enforce a generic calculation method to simplify adaptative toolpath generation. A state of the art realized in machining and robotics proposes to investigate the use of kinematical manipulability polytopes to represent kinematical capacities. An analysis of the polytopes and of the workpiece allows to generate toolpaths with a controlled feedrate and a decreasing time in 5 axes positionned milling and in 5 axes continous milling. This formalism highlights strong interactions between milling strategy parameters (workpiece setup, feed direction, tool orientation) and allows to prioritize specific parameters mix to have a controlled execution feedrate
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Rigatti, Aldo Marcel Yoshida [UNESP]. "Avaliação da força de usinagem e energia específica de corte no fresamento com alta velocidade de corte." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/94480.
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Este trabalho apresenta um estudo sobre a influência das condições de fresamento na força de usinagem e na energia específica de corte. Foram ensaiados dois tipos de materiais que sofreram diferentes formas de tratamentos térmicos. O aço CL 23 (Eaton Ltda) foi normalizado, resfriado ao forno e resfriado ao ar, e o aço COS AR 60 (Usiminas S/A) foi empregado na condição “como recebido” e tratado termomecanicamente, onde a microestrutura foi refinada a 1,7 m. Para o primeiro material, empregou-se 3 condições de usinagem, com parâmetros de corte fixos e distintos entre si, e para o segundo material, foram utilizadas 8 condições, em que todos os parâmetros variaram visando à aplicação da Análise de Variância (ANOVA). Os ensaios de fresamento de topo concordante a seco foram conduzidos em um centro de usinagem CNC de 11 kW de potência e rotação do eixo-árvore de 7.500 rpm. Empregou-se ferramenta de diâmetro 25 mm com dois insertos de metal duro revestidos com TiN e TiNAl. A força de usinagem foi obtida utilizando-se um dinamômetro piezelétrico de 3 componentes e sistema de aquisição, cujos sinais foram pós-processados para o cálculo da força de usinagem máxima, força de usinagem RMS e energia específica de corte. Os resultados apontam para uma influência da condição de usinagem sobre a força de usinagem e energia específica de corte. A condição com alta velocidade de corte (HSC - High-Speed Cutting) apresentou menores forças de usinagem e maiores energias específicas de corte. A usinagem assumida como convencional, apresentou maiores níveis de força de usinagem e energia específica menores. A força de usinagem se mostrou estatisticamente dependente da profundidade de usinagem e a energia específica do avanço da ferramenta. A velocidade de corte influiu de forma significativa na força de usinagem e na energia específica de corte...
This research deals with the influence of milling conditions on machining force and specific cutting energy. Two kind of workpiece materials thermally treated were used on tests. CL23 carbon steel (Eaton Ltda) was normalized, furnace cooled and air cooled and COS AR 60 carbon steel (Usiminas S/A) was employed in “as received” and refined grains (1.7 m) conditions. For the first material, three machining conditions were applied with constant and different cutting parameters. For the second steel, eight machining conditions were implemented where all cutting parameters varied aiming at application of Variance Analysis (ANOVA). The machining tests were carried out by using dry end milling under down milling strategy in a CNC machining center with 11 kW power and 7,500 rpm spindle speed. A 25 mm diameter endmill with two inserts (TiN and TiNAl coatings) was used. The machining force was measured by means of 3-components piezoelectric dynamometer and acquisition system, whose signals were post-processed in order to calculate the maximum machining force, RMS machining force and specific cutting energy. The results show the cutting condition influences on all researched variables. High-speed cutting (HSC) decreased the machining force and increased the specific cutting energy. The milling named conventional condition elevated the machining force and diminished the specific cutting energy. The depth of cut was statistically influent on machining force and the feed per tooth was determinant for specific cutting energy. The cutting speed influenced significantly on machining force and specific cutting energy. Microstructural condition of workpiece material demonstrated to be important over studied variables only when hardness values were different significantly. The results of specific cutting energy from this work present good correlation with those obtained from theoretical models proposed by Taylor, Kienzle, ASME, AWF and Sandvik
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Včelica, Josef. "Odkládací zařízení pro výměnné hlavy obráběcího centra." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228349.
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Diploma work deal winth resolution automatic heads for high-speed shaping centers exchangas, so there was not those exchanges need of the human factor. It meaning that will using element automatic interface directly to programme as are Ball screw drives, ball rail systems, hydraulic element atc.
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Pepin, Faustin. "Obrobitelnost kompresních kol z titanových slitin." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230048.
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Nespornou vyhodou počítačem podporované výroby (CAM) je výrazná časová úspora při přípravě obráběcího programu. Asociativita je jedním z řešení, její místo v rámci přípravy výrobku se nachází mezi hlavní konstrukcí a technologií podniku. Pro studium asociativity byl použity CAD/CAM modely kompresoru, který díky své komplexní geomtrii posloužil jaky dobrý příklad. Tato práce se podtrhuje omezené možnosti asociativity, především pokud jde o realizaci obráběcího programu pro součást tvořenou více prvky. Dále v této studii budou prezentovány jisté možnosti zlepšení procesu. Studie asociativity v této práci je zaměřena především na obrábění, tedy její aplikace jsou využívány zejména ve oborech jako je automobilový průmysl, letectví, kosmický průmysl či stavebnictví. Kompresor studovaný v této práci je vyroben ze slitiny titanu Ti-6Al-4V a jedná se o součást využívanou v kosmickém průmyslu. Jelikož se jsou jeho rozměry velmi malé, jsou pro jeho obrábění nezbytné velmi přesné nástroje a vysoké řezné rychlosti. Tato práce představuje odlišné strategie obrábění navrhnuté pro výrobu kompresoru, společně s analýzou výsledků. Po počáteční přípravě výroby následují dvě hlavní etpy : editace programu v CATII V5 a jeho ověření v NCSimul8.
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Duong, Tan Quang. "Commande à gains variables de l’erreur de contour pour l’usinage multiaxes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC009/document.
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Les techniques d’usinage avancées sont un élément indispensable du développement des industries manufacturières. L’une de ces techniques, l’usinage à grande vitesse, constitue le sujet principal de cette thèse de doctorat. Ainsi, l’objectif majeur des travaux vise à améliorer la précision de contour dans le contexte de l’usinage multiaxes à grande vitesse de surfaces de forme libre, en agissant directement au niveau des boucles de commande d’axe. Pour cela, une première étape consiste à élaborer une stratégie permettant d’estimer le plus précisément possible l’erreur de contour pour différentes configurations de l’outil. Cette erreur de contour est ensuite minimisée grâce à l’adaptation hors ligne, pour un profil de pièce donné, des gains proportionnel et d’anticipation des régulateurs des boucles d’asservissement de la position de chaque axe. L’adaptation de ces gains est réalisée via un algorithme d’optimisation à l’aide d’un modèle non-linéaire du comportement de la machine, en considérant en particulier les frottements sur chacun des axes. L’optimisation permettant d’obtenir les gains des correcteurs des boucles de régulation tient compte des contraintes en termes de limitations cinématiques des axes (vitesse, accélération et jerk), de stabilité des boucles d’asservissement et de limites au niveau des courants des moteurs. Afin d’en faciliter la mise en oeuvre dans un cadre industriel, les stratégies développées s’avèrent directement implantables au sein des commandes numériques actuellement sur le marché, exploitant toutes les possibilités de la structure de commande classique de l’entraînement d’axeThe advanced machining techniques are always the backbone of the manufacturing industries. Among such techniques, high speed machining is the main subject of this PhD thesis. Indeed, the main objective of this work is to improve the contouring accuracy in multi-axis high speed machining of free-form surfaces, directly acting inside the axis control loops. To do that, a first step aims at elaborating a strategy to estimate as accurately as possible the contour error for different tool configurations. This contour error is then minimized by means of an off-line adaptation for a given profile of the proportional and feedforward gains of the axis position loop controllers. This gain adaptation is performed via an optimization algorithm that considers a nonlinear model of the machine behaviour, in particular including friction related to each axis. This optimization leading to the controllers gains takes into account several constraints, including the axis kinematic (velocity, acceleration and jerk) limitations, the stability of the controlled loops and the motor current limits. Finally, to help their integration within an industrial framework, the developed strategies can be directly implemented in commercial CNC, by exploiting all possibilities of the classical control structure of axis drive
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Rigatti, Aldo Marcel Yoshida. "Avaliação da força de usinagem e energia específica de corte no fresamento com alta velocidade de corte /." Ilha Solteira : [s.n.], 2010. http://hdl.handle.net/11449/94480.
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Orientador: Alessandro Roger RodriguesBanca: Hidekasu Matsumoto
Banca: Eraldo Jannone da Silva
Resumo: Este trabalho apresenta um estudo sobre a influência das condições de fresamento na força de usinagem e na energia específica de corte. Foram ensaiados dois tipos de materiais que sofreram diferentes formas de tratamentos térmicos. O aço CL 23 (Eaton Ltda) foi normalizado, resfriado ao forno e resfriado ao ar, e o aço COS AR 60 (Usiminas S/A) foi empregado na condição "como recebido" e tratado termomecanicamente, onde a microestrutura foi refinada a 1,7 m. Para o primeiro material, empregou-se 3 condições de usinagem, com parâmetros de corte fixos e distintos entre si, e para o segundo material, foram utilizadas 8 condições, em que todos os parâmetros variaram visando à aplicação da Análise de Variância (ANOVA). Os ensaios de fresamento de topo concordante a seco foram conduzidos em um centro de usinagem CNC de 11 kW de potência e rotação do eixo-árvore de 7.500 rpm. Empregou-se ferramenta de diâmetro 25 mm com dois insertos de metal duro revestidos com TiN e TiNAl. A força de usinagem foi obtida utilizando-se um dinamômetro piezelétrico de 3 componentes e sistema de aquisição, cujos sinais foram pós-processados para o cálculo da força de usinagem máxima, força de usinagem RMS e energia específica de corte. Os resultados apontam para uma influência da condição de usinagem sobre a força de usinagem e energia específica de corte. A condição com alta velocidade de corte (HSC - High-Speed Cutting) apresentou menores forças de usinagem e maiores energias específicas de corte. A usinagem assumida como convencional, apresentou maiores níveis de força de usinagem e energia específica menores. A força de usinagem se mostrou estatisticamente dependente da profundidade de usinagem e a energia específica do avanço da ferramenta. A velocidade de corte influiu de forma significativa na força de usinagem e na energia específica de corte... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This research deals with the influence of milling conditions on machining force and specific cutting energy. Two kind of workpiece materials thermally treated were used on tests. CL23 carbon steel (Eaton Ltda) was normalized, furnace cooled and air cooled and COS AR 60 carbon steel (Usiminas S/A) was employed in "as received" and refined grains (1.7 m) conditions. For the first material, three machining conditions were applied with constant and different cutting parameters. For the second steel, eight machining conditions were implemented where all cutting parameters varied aiming at application of Variance Analysis (ANOVA). The machining tests were carried out by using dry end milling under down milling strategy in a CNC machining center with 11 kW power and 7,500 rpm spindle speed. A 25 mm diameter endmill with two inserts (TiN and TiNAl coatings) was used. The machining force was measured by means of 3-components piezoelectric dynamometer and acquisition system, whose signals were post-processed in order to calculate the maximum machining force, RMS machining force and specific cutting energy. The results show the cutting condition influences on all researched variables. High-speed cutting (HSC) decreased the machining force and increased the specific cutting energy. The milling named conventional condition elevated the machining force and diminished the specific cutting energy. The depth of cut was statistically influent on machining force and the feed per tooth was determinant for specific cutting energy. The cutting speed influenced significantly on machining force and specific cutting energy. Microstructural condition of workpiece material demonstrated to be important over studied variables only when hardness values were different significantly. The results of specific cutting energy from this work present good correlation with those obtained from theoretical models proposed by Taylor, Kienzle, ASME, AWF and Sandvik
Mestre
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Zapletal, Radek. "Pohon svislého suportu obráběcího centra lineárním motorem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-264924.
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The diploma dissertation deals with the mechanism of vertical movement of a saddle of high-speed machining centre which is made by the Trimill company. The movement of vertical alloy saddle is solved by ball screw. The solution could be improved by replacing the ball screw by linear motor. This will dramatically improve the dynamics of the movement of the vertical saddle. In addition, if the weight is compensated by pneumatic relief and the construction is welded, the dynamics will further improve.
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Hassini, Sami. "Qualification multi-critères des gammes d'usinage : application aux pièces de structure aéronautique en alliage Airware®." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22587/document.
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L’optimisation des gammes d'usinage n’est pas aisée, car elle souffre de deux lacunes importantes. La première est axée sur l'adaptabilité des gammes existantes aux moyens actuels de production et à leurs évolutions au fil des années pour répondre aux évolutions technologiques. Le second point concerne, l’absence de prise en compte du comportement mécanique de la pièce durant l'usinage dans l'élaboration de la gamme. Ces travaux de thèse abordent ces problématiques dans le cadre du projet FUI OFELIA. Ils étudient, dans un premier temps l'influence de la gamme d’usinage sur la déformation de la pièce. L'objectif est de pouvoir prédire le comportement mécanique de la pièce pour identifier les gammes minimisant les déformations. Le second point s'intéresse à l’évaluation multicritères des gammes de fabrication. Les critères retenus prennent en compte la déformation de la pièce, la productivité à travers une estimation rapide des temps d'usinage et la recyclabilité des copeaux obtenus lors de l'usinage. D’autre part, nous proposons un modèle géométrique des états intermédiaires de la pièce durant l’usinage pour à la fois évaluer les gammes de fabrication et conduire les calculs de simulation de la déformation de la pièce durant l’usinageThe optimization of machining sequences is not easy because it suffers from two major shortcomings. The first focuses on the adaptability of existing ranges to current production facilities and their evolution over the years to respond to technological developments. The second point concerns the lack of consideration in the mechanical behavior of the part during the development of machining sequence. This thesis addresses these in relation to the FUI OFELIA project. At first, they study the influence of the machining parameters on the deformation of the workpiece. The aim is to predict the mechanical behavior of the part to identify recommendations with minimal distortion. The second issue deals with multi-criteria evaluation of manufacturing ranges. The criteria take into account are the deformation of the workpiece, productivity through a quick estimate of machining time and recyclability of chips produced during machining. On the other hand, we propose a geometric model of the intermediate states of the workpiece during machining in order to both assess the manufacturing recommendations and to drive the simulation calculations of the deformation of the workpiece during machining
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Jesus, Edilson Rosa Barbosa de. "FERRAMENTAS DE USINAGEM EM AÇO RÁPIDO AISI M2 OBTIDO POR CONFORMAÇÃO POR SPRAY." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-11072007-073936/.
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O objetivo do presente trabalho foi à obtenção de aço rápido tipo AISI M2 pela técnica da conformação por spray e a avaliação deste, quanto ao seu desempenho quando aplicado como ferramenta de usinagem. O material obtido foi laminado a quente com razões de redução de 50 e 72%, resultando em placas a partir das quais foram confeccionadas pastilhas intercambiáveis para realização de testes de usinagem. O desempenho das pastilhas obtidas a partir do material conformado por spray e laminado a quente, foi confrontado com o de pastilhas confeccionadas a partir de material processado convencionalmente (lingotamento convencional), e com material processado pela técnica da metalurgia do pó (MP). As variações do material obtido por conformação por spray, assim como também os demais materiais, foram caracterizados química, física, mecânica e microestruturalmente. Adicionalmente, foram realizados testes de usinagem para avaliação de desempenho do material quando submetido a condições reais de trabalho. Os resultados da caracterização dos materiais evidenciaram o potencial da técnica de conformação por spray, em possibilitar a obtenção de materiais com boas características e propriedades. Para as condições de processamento, conformação mecânica e de tratamentos térmicos aplicados neste trabalho, às análises dos resultados dos testes de usinagem revelaram um comportamento muito próximo entre todos os materiais de ferramenta utilizados. Procedendo a uma análise mais refinada dos resultados dos testes de usinagem contínua, foi verificado um desempenho ligeiramente superior para o material obtido pela técnica da metalurgia do pó (MP), seguido pelo material obtido pela técnica da metalurgia convencional, o qual apresentou uma vantagem mínima em relação ao obtido pela técnica da conformação por spray e laminado com redução de 72%. Por fim, o desempenho inferior ficou por conta do material obtido pela técnica da conformação por spray e laminado com redução de 50%, o qual apresentou os maiores valores de desgaste.The aim of the present work was the obtention of AISI M2 high-speed steel by spray forming technique and the material evaluation when used as machining tool. The obtained material was hot rolled at 50% and 72% reduction ratios, and from which it was manufactured inserts for machining tests. The performance of inserts made of the spray formed material was compared to inserts obtained from conventional and powder metallurgy (MP) processed materials. The spray formed material was chemical, physical, mechanical and microstructural characterised. For further characterisation, the materials were submitted to machining tests for performance evaluation under real work condition. The results of material characterisation highlight the potential of the spray forming technique, in the obtention of materials with good characteristics and properties. Under the current processing, hot rolling and heat treatments condition, the analysis of the results of the machining tests revealed a very similar behaviour among the tested materials. Proceeding a criterious analysis of the machining results tests, it was verified that the performance presented by the powder metallurgy material (MP) was slight superior, followed by conventional obtained material (MConv), which presented a insignificant advantage over the spray formed and hot rolled (72% reduction ratio) material. The worst result was encountered for the spray forming and hot rolled (50% reduction ratio) material that presented the highest wear values.
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Gassara, Bassem. "Conditions de coupe en fraisage à grande vitesse : effet de la variation de la vitesse d’avance." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/10977/1/gassara.pdf.
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Dans le processus de fabrication en fraisage à grande vitesse ‘FGV’, l’étude de la réaction de la machine au cours de l’usinage est une tâche très délicate et importante. En effet, l’identification du comportement de la machine nécessite la modélisation de la loi de mouvement des axes et de la trajectoire réelle aux niveaux des discontinuités. Le nombre important de discontinuités engendrent une instabilité de la vitesse de déplacement des axes, ce qui implique une augmentation du temps d’usinage et un non-respect de la vitesse d’avance programmée, se traduisant par des problèmes de productivité et une sous-estimation du coût de l’usinage pour l’industriel. L’objectif de cette thèse est de développer un outil informatique qui permet de calculer la vitesse d’avance et de faire une estimation précise du temps de cycle pour n’importe quelle trajectoire générée par un logiciel de FAO. Pour ce faire, nous avons déterminé un modèle qui permet d’identifier le comportement cinématique des axes d’un centre d’usinage en FGV pour toute forme de trajectoire. À partir de la modélisation de la variation de la vitesse d’avance, nous avons déterminé le temps réel selon les trajectoires et l’erreur imposée par le bureau des méthodes. Enfin, nous utilisons ces résultats pour mettre en place une méthodologie pour l’aide au choix du diamètre de l’outil et de la stratégie d’usinage. Afin de valider les modèles et les méthodologies développés, une étude expérimentale a été réalisée sur des applications didactiques et industrielles.
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Baizeau, Thomas. "Développements expérimentaux et numériques pour la caractérisation des champs cinématiques de la coupe de l’acier 100 CrMo 7 durci pour la prédiction de l’intégrité de surface." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0054/document.
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Aujourd'hui, les méthodes de corrélation d'images sont largement utilisées pour la caractérisation et le suivi temporel des essais mécaniques. Cependant dans le domaine de l'usinage, ces méthodes sont très peu employées pour l'étude en pointe d'outil de la coupe par manque d'accessibilité, de la faible taille de la zone observée et des fortes déformations dans la zone de coupe. Dans cette thèse, nous mettons en application la technique de corrélation d'images pour l'étude et la caractérisation des champs cinématiques induits dans la matière usinée, durant des essais de coupe conduits avec des conditions opératoires représentatives des opérations industrielles. Ces conditions nous ont permis de développer, en premier lieu, des outils expérimentaux et numériques. Puis, les performances du dispositif expérimental ainsi que les incertitudes de corrélation ont été quantifiées. Différentes stratégies d'exploitation des images ainsi que des outils numériques pour la mesure des caractéristiques de la coupe sont proposés. Ensuite, nous avons développé un outil de corrélation d'images intégrée pour la mesure des efforts dynamiques grâce à un modèle analytique. Pour valider l'ensemble des méthodes, des essais de rabotage, d'abord dans un alliage d'aluminium, puis dans un acier 100~CrMo~7 traité thermiquement, ont été conduits. Ils ont permis de quantifier les champs cinématiques ainsi que les caractéristiques de la coupe. Enfin ces outils ont été appliqués pour la prédiction de l'intégrité de surface engendrée par une géométrie 3D d'outil de coupe dans le matériau durNowadays, digital image correlation (DIC) methods are widely employed to the mechanical testing characterization and their temporal monitoring. However in the machining field, to study the cutting process at the tool edge, these methods are not commonly applied due to the poor accessibility, the size of the observed area and the large strain occurring herein. In this study, the kinematic fields induced in the material by the cutting process are characterized and analyzed at industrial cutting conditions. In order to take and treat the pictures of the cut, experimental and numerical techniques have been first established. Then, the experimental setup performances and the uncertainties of the DIC were quantified. Different images selection strategies for the DIC and numerical post-processing algorithm for measuring the characteristics of the cut were proposed. Furthermore, a DIC integrated approach based on an analytical model was developed to record dynamics cutting forces. Trials in orthogonal configuration were performed and analyzed to validate the developed procedures first in an aluminium alloy, then in a 100~CrMo~7 hardened steel. The kinematics fields and the macroscopic data of the cut were successfully measured thanks to these tools. Finally, they were used for the prediction of the surface integrity induced by a 3D cutting edge in the hard material
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Senecaut, Yannick. "Vers une maîtrise objective des conditions de contact frottant en usinage à grande vitesse : intégration des phénomènes tribologiques et du comportement métallurgique." Thesis, Valenciennes, 2015. http://www.theses.fr/2015VALE0037/document.
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Dans les approches numériques pour l'usinage à grande vitesse, le comportement rhéologique des matériaux usinés est généralement décrit par une loi de Johnson Cook et le frottement à l’interface par un coefficient constant de type Coulomb. Une première approche propose de déterminer une loi de frottement à paramètres multiples pour des basses températures combinées à des vitesses de glissement élevées au moyen d'un tribomètre. Les résultats expérimentaux sont comparés à un modèle numérique et une méthode inverse est utilisée pour minimiser l'erreur entre des simulations numériques et expérimentales sur les forces tangentielles et normales. Cette méthode permet de récupérer un coefficient de frottement de type Coulomb qui est associé à la pression locale, la température et la vitesse de glissement. La réalisation de plusieurs essais fournit une loi de frottement à paramètres multiples pour des vitesses de glissement élevées et des basses températures. Une seconde étude est menée sur les phénomènes microstructuraux intervenant à l’interface outil-copeau. De nombreuses études ont montré que les phénomènes de recristallisation dynamique apparaissent lors de l'usinage dans l'interface outil-copeau. La loi de Johnson Cook ne comprend pas de tels phénomènes. Ainsi, les modèles rhéologiques spécifiques basés sur la métallurgie sont introduits pour tenir compte de ces phénomènes de recristallisation dynamique. Un modèle éléments finis de la coupe orthogonale à deux dimensions est développé avec le logiciel Abaqus Explicit en utilisant une formulation ALE. Ce modèle éléments finis peut alors prédire la formation des copeaux, les températures d'interface, les longueurs de contact et les forces de coupe. De nombreux essais spécifiques sont réalisés sur un banc d'essai de coupe orthogonale et un tribomètre grande vitesse sur un acier AISI 1045 et avec un outil en carbure non revêtu. Les résultats expérimentaux sont ensuite comparés aux simulations numériques. Ces deux approches montrent qu’il est nécessaire, afin d’optimiser les modèles de coupe orthogonale, de prendre en compte une loi de frottement à paramètres multiples qui tient compte des pressions, températures et vitesses de glissement locales et d’intégrer une loi de comportement rhéologique à base métallurgiqueIn numerical approaches for high speed machining, the rheological behavior of machined materials is generally described by Johnson Cook law and the friction at the interface by a constant coefficient of Coulomb. A first approach proposes to determine a multiparameter friction law for low temperatures in combination with high sliding speeds by means of a tribometer developed by Meresse et Al. [Mer11]. The experimental results are compared to a numerical model and a inverse method is used to minimize the error between the numerical and experimental simulations on tangential and normal forces. This method allows to recover a Coulomb friction coefficient. This one is associated with the local pressure, temperature and sliding velocity. Several tests provide a multiparameter friction law for higher sliding speeds and low temperatures. A second study is conducted on the microstructural phenomena occurring at the tool-chip interface. Numerous studies have shown that the dynamic recrystallisation phenomena appear during machining at the interface. Johnson Cook law excludes such phenomena. Thus, specific rheological models based on metallurgy are introduced to take into account the dynamic recrystallization phenomena. Two empirical models proposed by Kim et al. [Kim03] and Lurdos [Lur08] are studied. A two-dimensional finite element model of the orthogonal cutting is developed with Abaqus Explicit software using an ALE formulation. This finite element model can predict chip formation, interface temperatures, contact lengths and cutting forces. Many specific tests are performed with an orthogonal cutting test bench and with an high speed tribometer on an AISI 1045 steel. The experimental results are then compared with numerical simulations. Both approaches show that it is necessary to optimize the orthogonal cutting model, to take into account a multi-parameter friction law that considers the local pressures, temperatures, and sliding velocities and to integrate a rheological behavior law based on mettalurgy
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Salazar, Carlos Eddy Valdéz. "Avaliação através da inspeção magnética da condição superficial de anéis de rolamento de aço DIN 100Cr6 após torneamento duro a seco." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-11052009-174233/.
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O presente trabalho visa apresentar informações que viabilizem a fabricação de componentes de rolamentos com limites superiores de resistência à fadiga, com a intenção de proporcionar uma vida útil maior ao rolamento, e, também, a otimização da fabricação das peças, dispensando em alguns casos o processo final e usual de retificação, o que implica uma redução de custos. As motivações deste estudo são a geração de altas tensões residuais compressivas no torneamento duro-seco a altas velocidades, a aplicação do RMB como técnica de medição das tensões residuais em aço 100CrMn6 e a otimização da qualidade/custos na fabricação de rolamentos. Para atingir essas metas, será estudada a influência dos parâmetros da usinagem (velocidade de corte (Vc), avanço (a), penetração (p) e desgaste da ferramenta (VB)) na geração das tensões residuais superficiais (sR) e sobre as forças de torneamento (Fc, Fa, Fp), em anéis internos de rolamentos cônicos de aço DIN 100CrMn6 endurecidos termicamente, procurando-se estabelecer uma correlação entre o desgaste da ferramenta e os referidos esforços e tensões residuais. Na etapa experimental, será utilizado um planejamento fatorial completo para executar os ensaios e medições projetadas. No ensaio de torneamento, serão medidas as forças de corte utilizando-se, para isso, um dinamômetro piezoelétrico. Em seguida, serão efetuadas medições de rugosidade. Também será realizado o estudo da microestrutura através da análise metalográfica. As tensões residuais serão medidas utilizando-se o método do furo-cego com extensometria elétrica, e as medidas das alterações microestruturais superficiais serão realizadas pela técnica do Ruído Magnético de Barkhausen (RMB). Serão correlacionados os valores de tensão residual obtidos pela técnica do furo com o RMB.The present work presents information for the manufacturing of ball bearings components with higher limits of resistance to fatigue, enabling a longer useful life and also the optimization of the production of the pieces, making the usual and final process of grinding unnecessary, which would result in a costs reduction. The motivations of this study are the generation of compressive high residual stress in the hard-dry turning at high speeds, the application of the MBN as technique of measurement of the residual stress in steel 100CrMn6, and the optimization of the quality/costs in the manufacturing of ball bearings. In order to achieve these purpose, the work will study the influence of the machining parameters (cutting speed (Vc), feed rate (a), depth of cut (p), and wear of tool (VB)) in the generation of the superficial residual tensions and also the turning forces (Fc, Fa, Fp), in internal conical rings of ball bearings of steel 100CrMn6 thermally hardened, seeking to find a correlation between the stress of the tool and the referred efforts. In the experimental phase, a complete factorial planning will be used to perform the tests and measurements projected. In the turning tests, the cutting forces will be measured using a piezoelectric dynamometer. After that, measurements of superficial roughness will be performed. Also, the study of the microstructure will be made through the metallographic analysis. The residual tensions will be measured using the strain gage hole-drilling method and the measurement of the superficial microestrutural alterations will be carried out using the technical of the magnetic Barkhausen noise (MBN). The values of residual tension obtained by the hole-drilling will be correlated with the RMB.
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Silveira, Luciana Leite. "Resistência à corrosão e cavitação de revestimentos FeMnCrSi depositados por processos de aspersão térmica de alta velocidade." Universidade Tecnológica Federal do Paraná, 2018. http://repositorio.utfpr.edu.br/jspui/handle/1/2965.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)O processo de desgaste por cavitação e corrosão em componentes e sistemas hidrodinâmicos reduz drasticamente a eficiência operacional, levando a grandes perdas econômicas. O uso de revestimentos de alta resistência ao desgaste tem sido estudado como solução para o problema de corrosão e cavitação no ambiente industrial. Os processos de aspersão térmica são reconhecidos como uma excelente abordagem para aplicação de revestimentos de alta resistência, pois permitem depositar revestimentos com menor alteração do substrato. O processo oxi-combustível de alta velocidade (HVOF) produz revestimentos de altas densidade e coesão. O processo ar-combustível de alta velocidade (HVAF) é atualmente um processo alternativo ao HVOF, apresentando propriedades equivalentes e muitas vezes superiores às deste processo e com menor custo operacional. Esta pesquisa apresenta o uso dos processos HVOF e HVAF para deposição de revestimentos FeMnCrSi, com o objetivo de estudar os efeitos do processo de aspersão térmica e da composição química na morfologia, microestrutura e resistência à cavitação e corrosão dos revestimentos. Para isso, dividiu-se o trabalho duas partes, a primeira estudou revestimentos de mesma composição depositados por HVAF e HVOF quanto à sua morfologia e resistência à cavitação e corrosão. A segunda parte estudou a influência da composição química de quatro ligas experimentais na morfologia e resistência à cavitação e corrosão dos revestimentos. Foram realizadas a preparação metalográfica dos revestimentos, análise da morfologia e defeitos em microscópio ótico e microscópio eletrônico de varredura, ensaio de microdureza Vickers, ensaio de cavitação acelerada e de corrosão eletroquímica. Os revestimentos depositados pelo processo HVOF apresentaram maior quantidade de oxidação, relacionado ao uso de oxigênio como comburente neste processo. O processo HVAF apresentou menor oxidação de seus revestimentos, pelo uso de ar-comprimido como comburente ao invés de oxigênio, além de maiores valores de tenacidade à fratura, devido às maiores velocidades de partícula. Isto providenciou maior resistência à cavitação dos revestimentos HVAF. A resistência à corrosão dos revestimentos HVAF também foi superior à dos HVOF, devido a uma menor presença de óxidos nos revestimentos, por estes facilitarem a penetração de íons no revestimento, levando à corrosão interna. A composição química dos revestimentos depositados por HVAF teve menor influência na oxidação dos mesmos, assim como na tenacidade à fratura destes. A adição de Boro não foi benéfica para a resistência à cavitação. A resistência à corrosão dos revestimentos foi positivamente influenciada pela presença de Níquel. Já para a corrosão localizada, um maior teor de Cromo foi determinante na maior resistência dos revestimentos.
The cavitation and corrosion wear process on hydrodynamic components and systems dramatically reduces operational efficiency, leading to great economic losses. The use of wear resistant coatings has been studied as a solution to the problem of corrosion and cavitation in the industrial environment. The thermal spray processes are recognized as excellent approach to implementing high strength coatings as they allow the deposition of coatings with lower substrate change. The high velocity oxy-fuel (HVOF) process produces coatings with high density and cohesion. The high velocity air-fuel process (HVAF) is currently an alternative process to the HVOF, presenting equivalent and often superior properties to this process and at a lower operational cost. This research presents the use of HVOF and HVAF processes for the deposition of FeMnCrSi coatings, with the intent of studying the effects of the thermal spraying process and the chemical composition on the morphology, microstructure and resistance to cavitation and corrosion of the coatings. The work was divided in two parts, the first studied coatings of the same composition deposited by HVAF and HVOF as its morphology and resistance to cavitation and corrosion. The second part studied the influence of the chemical composition of four experimental alloys on the morphology and resistance to cavitation and corrosion of the coatings. The metallographic preparation of the coatings, analysis of morphology and defects in optical microscope and scanning electron microscope, Vickers microhardness test, accelerated cavitation and electrochemical corrosion tests were performed. The coatings deposited by the HVOF process presented higher amount of oxidation, related to the use of oxygen as oxidizer in this process. The HVAF process presented less oxidation of its coatings, by the use of compressed air as oxidizer instead of oxygen, besides higher values of fracture toughness, due to the higher particle velocities. This provided greater resistance to cavitation of the HVAF coatings. The corrosion resistance of HVAF coatings was also higher than HVOF coatings, due to a lower presence of oxides in the coatings, as they facilitate the penetration of ions into the coating, leading to internal corrosion. The chemical composition of the coatings deposited by HVAF had less influence on their oxidation and fracture toughness. The addition of boron was not beneficial to cavitation resistance. The corrosion resistance of coatings was positively influenced by the presence of Nickel. As for localized corrosion, a higher Chromium content was determinant in the higher resistance of the coatings.
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Barcuch, Jakub. "Optimalizace nástrojové řezné geometrie pro vysokorychlostní obrábění tenkostěnných součástí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230450.
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The theoretical part of the thesis deals with materials used in the aircraft industry with a focus on aluminium alloys. Then it describes high speed machining, its characteristics and its comparison with conventional machining. The following chapters describe strategies of machining thin-walled parts and a description of vibration that occurs during machining. The practical part deals with selection appropriate tool geometry, machining of thin-walled parts and evaluation of their deflection during machining.
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Rodrigues, Alessandro Roger. "Estudo da geometria de arestas de corte aplicadas em usinagem com altas velocidades de corte." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-03072005-134755/.
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Trata do estudo experimental da energia específica de corte e sua relação com parâmetros de usinagem, características geométricas e tribológicas das ferramentas, e material da peça usinada. Dentre as variáveis investigadas são destaques a profundidade de usinagem, velocidade de corte, raio de ponta, geometria de quebra-cavaco, tipo de revestimento das ferramentas, dureza, microestrutura e composição química do material da peça. Os seguintes materiais foram empregados nos ensaios: aços SAE 1213, 1020, 1045, ASTM H13 recozido e temperado, e liga de alumínio 2024. As medições de energia específica foram realizadas em uma máquina Charpy instrumentada por meio de um dinamômetro piezelétrico e um encoder ótico rotacional. Vários resultados puderam ser comparados aos obtidos em torno e centro de usinagem CNC devidamente instrumentados. Testes na condição HSM foram implementados nas máquinas-ferramentas. Todas as variáveis pesquisadas mostraram exercer influência sobre a energia específica. O aumento da profundidade de usinagem em 2,3 vezes causou diminuição da energia específica em 21%, na usinagem da liga de alumínio 2024. A elevação da velocidade de corte em torno de 70% conduziu a uma queda da energia específica de 24% para o aço SAE 1020. A geometria da ferramenta influiu mais decisivamente na energia específica sob velocidades de corte convencionais que na condição HSM. Pequenas variações na geometria do quebra-cavaco dos insertos causaram diminuição da energia específica de até 29%, para velocidade de corte convencional, e de 14% para HSM, na usinagem do aço H13 temperado. Diversos resultados de energia específica de corte medidos pelo ensaio Charpy proposto por este trabalho apresentaram boa concordância com os valores equivalentes fornecidos pela literatura científicaThis thesis presents an experimental study about the specific cutting energy and its relation with cutting parameters, geometrical and tribological characteristics of tools, and workpiece material. Depth of cut, cutting speed, tool nose radius, chip-breaker geometry, tool coating, hardness, microstructure and chemical composition of the workpiece material are some investigated variables. The following workpiece materials were tested: SAE 1213, 1020, 1045, annealed and tempered ASTM H13 steels, and 2024 aluminum alloy. The specific cutting energy values were measured by using a Charpy machine instrumented through piezoelectric dynamometer and incremental optical encoder. Several results could be compared to ones from instrumented CNC lathe and machining center. Tests under HSM condition were carried out in machine-tools. All researched variables have influence over specific cutting energy. The depth of cut rise in 2.3x caused a decrease of specific cutting energy around 21% when machining 2024 aluminum alloy. The elevation of the cutting speed about 70% leaded to reduction of specific cutting energy around 24% when machining SAE 1020 steel. The tool geometry present more influence on specific cutting energy under conventional cutting speed than at high speed cutting. Small variations of tool chip-breaker geometries caused diminution of the specific cutting energy up to 29% for conventional cutting speed, and 14% on average for HSM condition when machining tempered ASTM H13 steel. Various specific cutting energy results obtained from the Charpy test proposed by this work presented a good concordance with equivalent ones provided by scientific literature
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Chiprout, Eli Carleton University Dissertation Engineering Electronics. "Moment-maching analysis of high-speed VLSI interconnect models." Ottawa, 1994.
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Pateloup, Sylvain. "Modélisations et aptitudes à l'emploi des machines-outils à structure parallèle : vers une optimisation dirigée du processus." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00609682.
Full textAbstract:
Les travaux de recherche présentés dans ce mémoire concernent la prédiction et l'amélioration des performances des machines-outils à structure parallèle dans le but de produire des pièces conformes à la qualité requise en un temps minimal. Le problème abordé permet de déterminer l'influence de la structure sur la productivité et la qualité de la pièce usinée dans le contexte de l'Usinage à Grande Vitesse de pièces automobiles et aéronautiques. Ce travail propose alors des avancées suivant deux axes fondamentaux : - la modélisation du comportement anisotrope de la cellule d'usinage ; - la proposition de nouvelles méthodes d'adaptation du processus.Ces deux axes sont dans un premier temps abordés vis-à-vis d'un objectif d'amélioration des temps de déplacement d'outil hors matière. La méthode développée nécessite l'élaboration d'un modèle cinématique des déplacements hors matière spécifique à chaque structure de machine outil et basé sur l'utilisation d'une loi de commande articulaire. Un outil d'aide à la mise en place d'un usinage sur machine-outil à structure parallèle est ensuite proposé. Cet outil repose sur un modèle numérique de comportement cinématique utilisant une loi de commande de déplacement dans le repère lié à la pièce permettant de prédire le temps d'usinage en fonction des trajectoires. L'optimisation du processus d'usinage s'appuie également sur la prédiction de la qualité d'usinage. Pour cela, un modèle expérimental basé sur une campagne de mesures effectuée sur la machine-outil considérée a été développé. Ces approches sont appliquées à des usinages de pièces industrielles sur la machine-outil PCI Tripteor X7. Leur originalité réside dans l'amélioration des performances des machines-outils à structure parallèle à partir de l'analyse du comportement durant l'usinage et permet, par conséquent, d'étendre leur domaine d'application.