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Wang, Duck Hyun. "Machining characteristics of graphite/epoxy composite /." Thesis, Connect to this title online; UW restricted, 1993. http://hdl.handle.net/1773/7115.
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Stjernstoft, Tero. "Machining of Some Difficult-to-Cut Materials with Rotary Cutting Tools." Doctoral thesis, KTH, Production Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3693.
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Automobile and aero industries have an increasing interestin materials with improved mechanical properties. However, manyof these new materials are classified as difficult-to-cut withconventional tools. It is obvious that tools, cutting processesand cutting models has to be devel-oped parallel to materialsscience. In this thesis rotary cutting tools are tested as analternative toexpensive diamond or cubic bore nitridetools.
Metal matrix composites mostly consist of a light metalalloy (such as aluminium or titanium) reinforced with hard andabrasive ceramic parti-cles or fibres. On machining, thereinforcement results in a high rate of tool wear. This is themain problem for the machining of MMCs. Many factors affect thelife length of a tool, i.e. matrix alloy, type, size andfraction of the reinforcement, heat treatment, cuttingconditions and tool properties.
In tests, the Al-SiC MMC formed a deformation layer duringmilling, probably affected by lack of cooling. The dominatingfactor for tool life was the cutting speed. Water jet or CO2cooling of turning did not provide dramatic increase in toollife. With PCD, cutting speeds up to 2000 m/min were usedwithout machining problems and BUE formation. Tool flank wearwas abrasive and crater wear created an "orange-peel type" wearsurface. PCD inserts did not show the typical increase in flankwear rate at the end of its lifetime.
The use of self-propelled rotary tools seems to be apromising way to increase tool life. No BUE was formed on therotary tool at high cutting data. The measurements indicatethat the rotary tool creates twice as good surface as PCDtools. The longest tool life was gained with an inclinationangle of 10 degrees. Tool costs per component will beapproximately the same, but rotary cutting tool allows higherfeeds and therefore a higher production rate and thus a lowerproduction cost.
The rotary cutting operation might have a potential toincrease productiv-ity in bar peeling. The lack of BUE withrotary cutting gives hope on higher tool life. The test resultsshow that tool wear was 27% lower with rotary cutting tools.Increase of cutting speed from 22 to 44 m/min did not affectcutting forces. This indicates that the cutting speed canincrease without significant change in tool wear rate.
Issues related to rotary cutting like cutting models,cutting processes, standards, tools and models have beendiscussed. A tool wear model with kinetic energy has beendiscussed.
KEYWORDS:Difficult-to-Cut material, Metal MatrixComposite (MMC), Machining, Machinability, Rotary Cutting Tool,Acoustic Emission
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Xu, Jinyang. "Numerical and experimental study of machining titanium-composite stacks." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0022/document.
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Dans l’industrie aérospatiale, l’utilisation des matériaux hybrides CFRP/Ti montre une tendance à la hausse en raison de leurs propriétés mécaniques/physiques améliorées ainsi que des fonctions structurelles plus flexibles. En dépit de leurs nombreuses applications, l’usinage CFRP/Ti en perçage en une seule passe reste le principal défi scientifique et technologique de l’assemblage multi-matériaux. Par rapport au coût de production élevé et le temps des recherches basées sur des approches exclusivement expérimentales de l’usinage multi-matériaux, cette étude a pour objectif d’amener une meilleure compréhension de la coupe CFRP/Ti à travers une approche physique hybride qui fait dialoguer les méthodes numériques et expérimentales. Un modèle EF utilisant le concept de zone cohésive a été développé pour étudier l’usinabilité anisotrope de pièces structurales CFRP/Ti à des fins d’assemblage. L’approche numérique explicite, par des études préliminaires, les mécanismes de coupe clés qui contrôlent l’usinage CFRP/Ti. Par la suite, l’approche expérimentale a été conduite sous différentes conditions d’usinage en configuration de coupe orthogonale et de perçage. Une attention spéciale a été consacrée aux effets des stratégies des séquences de coupe CFRP/Ti sur la formation des endommagements d’interface induits. Ces études expérimentales et numériques ont permit (i) d’expliciter les mécanismes physiques activés qui contrôlent la coupe à l’interface ainsi que les endommagements induits par celle-ci, (ii) de préciser les effets des différentes stratégies d’assemblage multi-matériaux sur l’usinage CFRP/Ti, (iii) de définir la classification d’usinabilité CFRP/Ti, et (iv) d’analyser enfin les effets paramétriques géométrie/matériau d’outil régissant l’opération d’usinage CFRP/TiIn modern aerospace industry, the use of hybrid CFRP/Ti stacks has experienced an increasing trend because of their enhanced mechanical/physical properties and flexible structural functions. In spite of their widespread applications, machining hybrid CFRP/Ti stacks in one-shot time still consists of the main scientific and technological challenge in the multi-material fastening. Compared to the high cost of pure experimental investigations on the multi-material machining, this study aims to provide an improved CFRP/Ti cutting comprehension via both numerical and experimental methodologies. To this aim, an FE model by using the cohesive zone concept was established to construct the anisotropic machinability of the bi-material structure. The numerical work aims to provide preliminary inspections of the key cutting mechanisms dominating the hybrid CFRP/Ti stack machining. Afterward, some systematic experimental work including orthogonal cutting and hole drilling was carefully performed versus different input cutting conditions. A special focus was made on the study of the effects of different cutting-sequence strategies on CFRP/Ti cutting output and induced interface damage formation. The combined numerical-experimental studies provide the key findings aiming to (i) reveal the activated mechanisms controlling interface cutting and subsequent interface damage formation, (ii) clarify the influences of different cutting-sequence strategies on hybrid CFRP/Ti stack machining, (iii) outline the machinability classification of hybrid CFRP/Ti stacks, and (iv) analyze finally the parametric effects of the material/tool geometry on cutting CFRP/Ti stacks
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TONELLO, KAROLINA P. dos S. "Compósitos de alumina com adições de NbC, TaC e TiC para aplicação em ferramentas de corte." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10206.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Liu, Jian. "Experimental study and modeling of mechanical micro-machining of particle reinforced heterogeneous materials." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5408.
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This study focuses on developing explicit analytical and numerical process models for mechanical micro-machining of heterogeneous materials. These models are used to select suitable process parameters for preparing and micro-machining of these advanced materials. The material system studied in this research is Magnesium Metal Matrix Composites (Mg-MMCs) reinforced with nano-sized and micro-sized silicon carbide (SiC) particles. This research is motivated by increasing demands of miniaturized components with high mechanical performance in various industries. Mg-MMCs become one of the best candidates due to its light weight, high strength, and high creep/wear resistance. However, the improved strength and abrasive nature of the reinforcements bring great challenges for the subsequent micro-machining process. Systematic experimental investigations on the machinability of Mg-MMCs reinforced with SiC nano-particles have been conducted. The nanocomposites containing 5 Vol.%, 10 Vol.% and 15 Vol.% reinforcements, as well as pure magnesium, are studied by using the Design of Experiment (DOE) method. Cutting forces, surface morphology and surface roughness are characterized to understand the machinability of the four materials. Based on response surface methodology (RSM) design, experimental models and related contour plots have been developed to build a connection between different materials properties and cutting parameters. Those models can be used to predict the cutting force, the surface roughness, and then optimize the machining process. An analytical cutting force model has been developed to predict cutting forces of Mg-MMCs reinforced with nano-sized SiC particles in the micro-milling process. This model is different from previous ones by encompassing the behaviors of reinforcement nanoparticles in three cutting scenarios, i.e., shearing, ploughing and elastic recovery. By using the enhanced yield strength in the cutting force model, three major strengthening factors are incorporated, including load-bearing effect, enhanced dislocation density strengthening effect and Orowan strengthening effect. In this way, the particle size and volume fraction, as significant factors affecting the cutting forces, are explicitly considered. In order to validate the model, various cutting conditions using different size end mills (100 &"181;m and 1 mm dia.) have been conducted on Mg-MMCs with volume fraction from 0 (pure magnesium) to 15 Vol.%. The simulated cutting forces show a good agreement with the experimental data. The proposed model can predict the major force amplitude variations and force profile changes as functions of the nanoparticles' volume fraction. Next, a systematic evaluation of six ductile fracture models has been conducted to identify the most suitable fracture criterion for micro-scale cutting simulations. The evaluated fracture models include constant fracture strain, Johnson-Cook, Johnson-Cook coupling criterion, Wilkins, modified Cockcroft-Latham, and Bao-Wierzbicki fracture criterion. By means of a user material subroutine (VUMAT), these fracture models are implemented into a Finite Element (FE) orthogonal cutting model in ABAQUS/Explicit platform. The local parameters (stress, strain, fracture factor, velocity fields) and global variables (chip morphology, cutting forces, temperature, shear angle, and machined surface integrity) are evaluated. Results indicate that by coupling with the damage evolution, the capability of Johnson-Cook and Bao-Wierzbicki can be further extended to predict accurate chip morphology. Bao-Wierzbiki-based coupling model provides the best simulation results in this study. The micro-cutting performance of MMCs materials has also been studied by using FE modeling method. A 2-D FE micro-cutting model has been constructed. Firstly, homogenized material properties are employed to evaluate the effect of particles' volume fraction. Secondly, micro-structures of the two-phase material are modeled in FE cutting models. The effects of the existing micro-sized and nano-sized ceramic particles on micro-cutting performance are carefully evaluated in two case studies. Results show that by using the homogenized material properties based on Johnson-Cook plasticity and fracture model with damage evolution, the micro-cutting performance of nano-reinforced Mg-MMCs can be predicted. Crack generation for SiC particle reinforced MMCs is different from their homogeneous counterparts; the effect of micro-sized particles is different from the one of nano-sized particles. In summary, through this research, a better understanding of the unique cutting mechanism for particle reinforced heterogeneous materials has been obtained. The effect of reinforcements on micro-cutting performance is obtained, which will help material engineers tailor suitable material properties for special mechanical design, associated manufacturing method and application needs. Moreover, the proposed analytical and numerical models provide a guideline to optimize process parameters for preparing and micro-machining of heterogeneous MMCs materials. This will eventually facilitate the automation of MMCs' machining process and realize high-efficiency, high-quality, and low-cost manufacturing of composite materials.Ph.D.
Doctorate
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
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Sedláček, Jan. "Efektivní obrábění vláknově vyztužených kompozitních materiálů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-233910.
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The objectives for this dissertation are to push forward the current state of knowledge in the area of machining fiber-reinforced plastic (FRP). The most common machining operation performed on these materials is drilling owing to the need for component assembly in mechanical pieces and structures. Among the defects caused by drilling, delamination appears as to be of the most critical and may occur at both the entrance and exit plane. A number of theoretical and experimental studies have been made to create an analytical model of delamination in composite laminates. In this dissertation, the critical thrust force (force which initiates the delamination) is predicted using linear elastic fracture mechanics - assuming Mode I. Delamination is investigated by studying the evolution of feed force and torque applied by the tool on the workpiece. A four components piezoelectric dynamometer KISTLER 9272 with special PC-software is used for measuring and evaluating of torque and cutting forces, when drilling two different composite materials: carbon/epoxy laminate fabricated by hand lay-up technique and glass/polyester composite made by pultrusion. Wear mechanisms and location of the wear on the tool are also investigated (with respect to cutting material). The tool wear is measured with help of a common workshop microscope and recorded with scanning electron microscope PHILIPS XL30. Drilling experiments are performed to give complex technical information (i.e. cutting conditions, tool geometry, tool wear and so on) which enables efficient machining of composite materials. Delamination-free drilling is given special emphasis in the experiments. Methods of statistical analysis (DOE) are used to determine which factors have the most influence on delamination.
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Chibane, Hicham. "Contribution à l'optimisation multi-objectif des paramètres de coupe en usinage et apport de l 'analyse vibratoire : application aux matériaux métalliques et composites." Thesis, Tours, 2013. http://www.theses.fr/2013TOUR4053/document.
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Les procédés de fabrication de pièces mécaniques par enlèvement de matière (tournage, fraisage, perçage, ...) connaissent une utilisation massive dans l’industrie aéronautique et l’automobile. Les pièces obtenues par ces procédés doivent satisfaire à des propriétés géométriques, métallurgiques et à des caractéristiques de qualité. Pour répondre à ces exigences, plusieurs essais expérimentaux basés sur le choix des conditions de coupe sont souvent nécessaires avant d’aboutir à une pièce satisfaisante. Actuellement, ces méthodes empiriques basées sur l’expérience des fabricants et des utilisateurs des outils coupants sont souvent très longues et coûteuses, donnent une large plage de choix des paramètres en fonction de leurs besoins. Toutefois, le coût très élevé d’un essai limite fondamentalement le nombre d’expériences, avoir une pièce respectant les caractéristiques souhaitées avec un coût acceptable devient une tâche difficileManufacturing processes of mechanical parts by removal of material (turning, milling, drilling ...) have extensive use in aeronautic and automobile industry. The components obtained using these methods must satisfy geometric properties, metallurgical and quality characteristics. To meet these requirements, several experimental tests based on the selection of cutting conditions are often necessary before manufacturing. Currently, these empirical methods based on the experience of manufacturers and users of cutting tools (charts, diagrams with experimental findings, ...) are often very lengthy and costly. However, the high cost of a trial limits the number of experiments, so to have a deserted component with an acceptable cost is a difficult task. The importance of cutting conditions monitored by limitations is related to the type of material to be machined, since it determines the behavior of the machining
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Kim, Dae-Wook. "Machining and drilling of hybrid composite materials /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/7041.
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Pretorius, Cornelius. "Machining of titanium alloys with ultra-hard cutting tool materials." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4385/.
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This research explores the relative merits of existing and novel ultra-hard tool materials for finish turning titanium alloys. Phase 1 of the experimental work comprised evaluating the machinability of Ti-6Al-2Sn-4Zr-6Mo when employing carbide tooling with respect to tool life, wear behaviour, workpiece surface integrity and cutting forces. The machinability of Ti-6Al-2Sn-4Zr-6Mo using PCBN tooling was evaluated in Phase 2 experiments. It was shown that even with the use of high pressure jet cooling, carbide and low content PCBN grade inserts were unsuitable for high-speed (~200 m/min) finish turning of titanium alloys. Phase 3 research evaluated the machinability of Ti-6Al-2Sn-4Zr-6Mo and Ti-6Al-4V when employing PCD tooling with respect to tool life, wear behaviour, workpiece surface integrity and cutting forces. Benchmark tests producing response surface models were developed using conventional low pressure fluid supply and were found to be suitable for the prediction of tool life, surface roughness and cutting force within the range of parameters studied. The PCD inserts significantly outperformed both carbide (by a factor > 24) and PCBN (by a factor > 12) tools in high-speed finish turning, although the performance varied depending on the PCD structure, edge geometry, period of engagement, undeformed chip thickness and jet fluid parameters.
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Lake, P. W. "Composite cutting tip and materials for mining tools." Thesis, Nottingham Trent University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375097.
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Chardon, Grégory. "Usinage de moules en matériaux composites, expression des contraintes liées au procédé." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00678330.
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L'étude présentée dans ce mémoire se focalise sur l'usinage de moules en matériaux composites, en considérant les problèmes d'état de surface et de gamme d'usinage. Les pièces de structure aéronautiques peuvent être obtenues par les procédés de fabrication de la famille LCM (Liquid Composite Molding). Ce procédé impose une température de fonctionnement élevée qui conduit à une dilatation du moule néfaste à la qualité de la pièce injectée. Pour remédier à ce problème, il est nécessaire de réaliser l'outillage dans un matériau à faible dilatation ou se comportant comme le matériau injecté. Pour cela, un matériau composite (Hextool™) est proposé en remplacement des moules métalliques conventionnels. L'étape d'usinage de forme est indispensable car elle donne les dimensions finales de l'outillage et conditionne le temps de polissage manuel nécessaire pour atteindre la rugosité arithmétique visée. Ce travail propose deux voies d'amélioration à travers l'étude micro-géométrique de l'opération de finition par outil coupant puis par outil abrasif. La première voie met en évidence l'existence d'une valeur minimale de rugosité accessible lors d'un usinage avec un outil coupant. L'analyse de ce phénomène permet de proposer une valeur de prise de passe radiale optimisant le ratio rugosité du moule / temps d'usinage. La deuxième conduit à la définition d'un outil abrasif utilisable sur un centre d'usinage. La faisabilité d'une telle opération et les capacités de cette technologie innovante sont discutées. Enfin, le choix des outils, des stratégies d'usinage et de la machine outil sont discutés et aboutissent à la proposition d'une gamme de référence pour l'usinage d'ébauche et de finition de moules en matériaux composites.
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Negarestani, Reza. "Laser cutting of carbon fibre-reinforced polymer composite materials." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/laser-cutting-of-carbon-fibrereinforced-polymer-composite-materials(90c7dab8-2b05-4098-aee7-d90a66b9face).html.
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Carbon fibre-reinforced polymer (CFRP) composite materials are in increasingly high demand, particularly in aerospace and automotive industries for reduced fuel consumption. This is due to their superior structural characteristics (both in fatigue and static conditions) and light weight. Anisotropic and heterogeneous features of these materials, however, have posed serious challenges in machining of CFRPs. Hence new machining technologies need to be investigated. Laser is a non-contact (eliminating toolwear) thermal process. Therefore, the thermal properties of the material are of crucial importance. Especially for composite materials which consist of different constituent materials. In CFRPs, carbon fibres are excellent conductors of heat (thermal conductivity of 50 W/(m.K)) while the polymer matrix is poor conductor (thermal conductivity of 0.1-0.3 W/(m.K)). This significant difference that can be similarly traced for other thermal properties such as heat of vaporisation and specific heat capacity are the source of defects in laser cutting of CFRP composites. Major quality challenges in laser cutting of these materials are delamination and matrix recession. Various laser systems and cutting techniques are investigated in this work to minimise these defects. Multiple-pass cutting using a high beam quality continuous wave (CW) mode fibre laser is found to be effective to minimise delamination at low power level and high scanning speeds. Multiple-pass cutting using nanosecond pulsed DPSS Nd:YAG laser is shown to reduce matrix recession. A novel technique using mixing of reactive and inert gases is introduced and demonstrated to minimise the matrix recession. In order to improve the quality and dimensional accuracy of CFRP laser machining, it is important to understand the mechanism of transient thermal behaviour and its effect on material removal. A three-dimensional model to simulate the transient temperature field and subsequent material removal is developed, for the first time, on a heterogeneous fibre-matrix mesh. In addition to the transient temperature field, the model also predicts the dimensions of the matrix recession during the laser machining process.
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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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Okeke, Christopher Igwedinma. "Threading and turning of aerospace materials with coated carbide inserts." Thesis, London South Bank University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297919.
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The first part of this study involve an evaluation of the performance of TiN and AlZ03 single layer coated cemented carbide tools when threading inclusion modified, 708M40T (En 19T) 817M40T (En 24T) and Jethete steels at high cutting conditions by monitoring tool wear, failure modes, post threading workpiece properties, micro and macro-surface alterations and subsurface microhardness variation of threaded surfaces. Test results show that flank wear was the dominant failure mode, increasing rapidly when machining at the top speed of 225 m min,l due to the high temperature generated which accelerates thermally related wear mechanisms. Tool life, surface finish, hardness variation and component forces during threading were influenced by the geometry of the cutting edge, shape of wear/length of wear along tool nose/cutting edge after threading. Formation of flake-like oxide debris on the worn inserts was found to increase with nickel content in the workpiece material. The Al20) coated carbide inserts with K05 - K20 substrate gave longer tool life, lower cutting forces, better surface finish! damages as well as minimum hardness variation after threading compared with the TiN coated VSX grade with P20-P30 substrates. This can be related to their superior hardness, density, transverse rupture strength as well as the unalloyed WC fine grained substrate (1/lm) in addition to the high hot hardness, excellent chemical stability and low thermal conductivity of the AlZ03 coating at elevated temperatures. A formula for tool rejection was also developed during this study based on the average flank wear (VBb) and growth in thread root (GTR) in order to establish a scientific basis for assessing wear of threading tools. The second part of this study involve single point turning of a nickel base, G263, alloy using rhomboid-shaped PVD coated (TiN/TiCN/TiN, TiAIN and TiZrN) carbide tools at high speed cutting conditions. The worn tool edges revealed adhesion of a compact fin-shaped structure of hardened burrs with saw-tooth edges. The compact structure also formed on the cut surface of the workpiece material. The use of coolant during machining tend to work harden the root of the burr thereby restricting tool entry at the cutting zone leading to the generation of excessive feed force which subjects the tool edge to premature fracture and consequently lower tool life. The serrated/saw-tooth like edges of the burr encourages abrasion wear on the tool flank face and the formation of shallow cavities/lateral cracks where fragments of hardened workpiece material are deposited causing deterioration of the machined surfaces. Tool life was generally influenced by the cutting conditions employed as well as the insert geometry. Increasing cutting conditions (speed, feed and depth of cut) led to chipping of the cutting edge and/or flaking of coating layers as well as notching and fracture of the cutting edge. These failure modes jointly contributed to lowering tool life during machining. The TiN/TiCN/TiN coated KC732 (Tool A) inserts with positive sharp edges gave overall performance at the optimum cutting conditions established under finishing operation. This is followed by the TiN/TiCN/TiN coated KC732 (Tool B), TiAlN coated KC313 (Tool C) and lastly the TiZrN coated KC313 (Tool D) inserts' with razor sharp edges. Under roughing operation, the ranking order of tool performance is the TiZrN coated KC313 (Tool D), TiN/TiCN/TiN coated KC732 (Tool A), TiAlN coated KC313 (Tool C) and lastly the TiN/TiCN/TiN coated KC732 {Tool B). The difference in tool geometry and coating materials contributed to the relative order of tool performance.
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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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Gekonde, Haron Ogega. "Influence of dynamic behaviour of materials on machinability." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/NQ42737.pdf.
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JESUS, EDILSON R. B. de. "Obtencao usinagem e desgaste de materiais compositos de matriz metalica processados via metalurgia do po." reponame:Repositório Institucional do IPEN, 1998. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10719.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Kim, Sangseop. "Determination of Wall Thickness and Height when Cutting Various Materials with Wire Electric Discharge Machining Processes." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/294.
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This thesis looks at the capabilities of cutting thin webs on Wire EDM machines that are difficult or impossible to machine using conventional methods. Covered is an investigation of how different material and web thickness affect the capability of machining thin-walled parts.
Five different metals are used for the test; Aluminum 6061 T6, Yellow Brass SS360, 420 Stainless Steel, D2 unheat-treated tool steel 25-30 RC, and D2 heat-treated tool steel 60-65 RC. The small parts were cut to a 6mm (0.2362 inch) height with six different wall thicknesses: 0.30mm (0.0118 inch), 0.25mm (0.0098 inch), 0.20mm (0.0078 inch), 0.15mm (0.0059 inch), 0.10mm (0.0039 inch), and 0.05mm (0.0020 inch). A Sodick AQ325L Wire EDM machine was utilized for testing.
The methods employed during the study include the following:
• Machine settings and offsets were limited to the default setting selected from the Sodick AQ325L database.
• Two different pre-test cuts were taken on the material to check for web bending during the cutting process.
• Hardness was tested for comparison of the web heights.
This thesis shows that bending increased as webs became thinner and that bending occurred toward the wire as the second side of the web was cut. Bending does affect the height of the web. Physical properties of materials also impacted the height of the web with the hardest material staying intact during the cutting process. This study shows that two factors, physical properties of materials and web thickness, significantly affect cutting results for thin web parts.
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Oosthuizen, G. A. "Innovative cutting materials for finish shoulder milling Ti-6A1-4V aero-engine alloys." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1561.
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Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2009.The titanium alloys have found wide application in the aerospace, biomedical and automotive industries. Soaring fuel prices and environmental concerns are the fundamental drivers that intensify the demand situation for titanium. From a machining viewpoint, one of the challenges companies face, is achieving high material removal rates while maintaining the form and function of the part. The ultimate aim for a machining business remains to make parts quickly. Conventional cutting speeds range from 30 to 100 m/min in the machining of Ti-6Al-4V. Milling this alloy faster however is challenging. Although titanium is becoming a material of choice, many of the same qualities that enhance titanium‟s appeal for most applications also contribute to its being one of the most difficult materials to machine. The author explored the potential for Polycrystalline diamond (PCD) inserts in high speed milling of Ti-6Al-4V, by trying to understand the fundamental causes of tool failure. The objective was to achieve an order of magnitude increase in tool life, while machining at high speed, simply by reducing some of the failure mechanisms through different cutting strategies. Tool wear is described as a thermo-mechanical high-cycle fatigue phenomenon. The capability of a higher material removal per tool life is achieved in the case of PCD inserts compared to Tungsten carbide (WC). The average surface roughness produced was relatively low. The collected chips were also analyzed. The work demonstrated progress over the performance reported in current literature. The work confirms that there is a region where a sufficiently high temperature in the cutting zone may contribute to extended tool life, provided that the tool material can withstand these extreme conditions.
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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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Sartkulvanich, Partchapol. "Determination of material properties for use in FEM simulations of machining and roller burnishing." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1167412216.
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Kosmák, Jaroslav. "Obrábění kalených ocelí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230778.
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Diploma thesis deals with machining of hardened steels. In the introductory section it is described the physical process of cutting and basic used technologies of machining. The next chapter provides an overview of cutting materials. Other chapters deal with the workpiece material and heat treatment. Furthermore, there is made a comparison of the cutting conditions while machining of hardened steels by tools from selected manufacturers. As the conclusion there is the economic evaluation.
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ALMEIDA, IVAN A. de. "Otimização do processo de usinagem de titânio com laser pulsado de neodímio." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11589.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Holík, Radek. "Návrh na zefektivnění opracování desek z kompozitních materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241848.
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This master thesis is dealing with the analysis of current technology of machining based on unconventional method of water jet cutting for sheet machining of composite materials. My goal is to analyze and calculate the cost of technologies. There is, in conclusion of the master thesis, the techno-economic evaluation and final decision whether it is appropriate to invest in a new technology or not.
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Strehler, Claudia. "Development of near net shaped Si3N4/SiC composites with optimised grain boundary phase for industrial wood machining." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-71329.
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The introduction of ceramics into the market of wood cutting tools has failed so far due to the generally low toughness of ceramics which is causing brittle failure of the cutting edge. A feasibility study showed that Si3N4/SiC composites with fine elongated β-Si3N4 grains are a promising material for industrial wood machining and outperform commercial standard tungsten carbide tools in terms of lifetime. However, they were produced by hot pressing followed by very costly diamond cutting and grinding. The costs associated with the above production route are too high for an industrial viability.
In this thesis Si3N4/SiC composites suitable for industrial wood milling are produced by a near net shape processing route including gas pressure sintering. These newly developed tools show less abrasive wear and consequently twice as long lifecycles than commercial standard tungsten carbide tools. Microscopic properties determine the performance of the Si3N4/SiC cutting tools. Therefore, an adequate selection of sintering additives is crucial. 12 wt% sintering additives are included in the composite as a combination of Al2O3 and the refractory oxides La2O3 and Y2O3. Important for the production of effective Si3N4/SiC wood cutting tools is the formation of a partly crystalline silicate phase within the multiple grain junctions during the final treatment by hot isostatic pressing. The use of MgO as a sintering additive for facilitating the densification of the Si3N4 ceramics inhibits the formation of the favourable silicate phase and must be avoided for the production of these wood cutting tools.
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PASOTTI, ROSA M. da R. "Obtencao e caracterizacao do composito Alsub2 Osub3-NbC e o efeito da adicao de Ysub2 Osub3 na sua sinterizacao." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10745.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Perončík, Martin. "Obrábění těžkoobrobitelných materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229217.
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Diploma thesis is specialized to solving of problems machining of diffi-cult machinable materials. There is carried out the analysis of difficult machinable materials in term of chemical composition, physical and mechanical properties. In the following it deals with analysis of machining, specification of geometry, material of cutting tools and cutting conditions.
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Reiter, Milan. "Obrábění žáruvzdorných keramických materiálů frézováním." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231462.
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Diploma thesis is focused on machining of refractory ceramics materials. The theoretical part describes the division of ceramics materials, their structure, manufacture and properties. This part also contains the division of refractory ceramics. In the second chapter, of ceramics materials are described machining. The latest chapter is focused on analyzing the machinability of ceramics materials R - SLI - K. During the experiment, cutting conditions were changed and cutting forces were checked. Then surface roughness was measured and tool wear was observed.
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Bukovský, Petr. "Obrábění rotačních součástí z kalených ocelí se zaměřením na stav povrchu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232047.
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The thesis deals with machining of rotating parts made from hardened steel. The introductory chapter describes the problems of turning and grinding. The next chapter deals with heat treatment and machined materials. The next lists the used cutting materials. Criteria for evaluating the quality of the surface. A selection of cutting materials for the machining of hardened steels from selected manufacturers. The final chapter is a comparison of the described technologies.
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Trčka, Radim. "Návrh na zefektivnění výroby rotační součásti." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318370.
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This diploma thesis deals with machining of rotating components made of composite material. Components of the two manufacturing technologies are compared. The aim of the thesis was to analyze and calculate the costs of the given technologies for different production batches. At the end of the diploma thesis there is a technological-economic evaluation and decision on which production technology will be used.
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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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Bukáček, Zdeněk. "Technologie obrábění tvrdých materiálů nástroji s definovanou geometrií břitu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228640.
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This master’s thesis is concerned with subject matter hard machining with defined geometry edge tools. Aim master’s thesis is analysis and parameters evaluation machined surface at hard machining. This master’s thesis contain a characteristic of hard materials, used technology for cutting operation, but also tools and cutting conditions suitable for hard machining. In the conclusion are parameters evaluation machined surface the workpiece.
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Kresa, Jakub. "Studie obrábění keramických materiálů broušením." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231435.
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This thesis is focused on ceramics materials in terms of their partition, properties, structure, manufacture and methods of their possible machining. The first part of this thesis is devoted to the distribution of ceramics materials, their structure, properties, and methods of production. Currently, ceramics materials are increasingly used in structural (engineering) applications therefore we deal with methods of effective machining of ceramic materials, to achieve part of the required shape, dimensions and surface quality. The evaluation of ceramic grinding test from the point of view of cutting forces and surface quality of the machined faces are presented in the last part of the thesis. The tested materials have been provided by company SEEIF Ceramics a.s.
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SANTOS, THAIS da S. "Micro-nanocompósitos de Al2O3/ NbC/ WC e Al2O3/ NbC/ TaC." reponame:Repositório Institucional do IPEN, 2014. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23599.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Barp, Denise Rippel Araújo. "Design e materiais : contribuição ao estudo do processo de corte de ágata por jato d'água em formas complexas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/18983.
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No estado do Rio Grande do Sul, estão localizadas importantes regiões de extração e processamento do material gemológico ágata. No Distrito Mineiro do Salto do Jacuí encontram-se as maiores jazidas de ágata do Brasil e do Mundo. No município de Soledade se concentram as principais empresas de beneficiamento e comércio de materiais gemológicos. Apesar da abundância de material, a maioria dos objetos produzidos apresenta baixo grau de inovação, os produtos oferecidos no mercado são muito semelhantes entre si e tem, em comum, a falta de diferencial e de utilização de processos que envolvam tecnologia. A ágata é geralmente exportada em estado bruto ou apresentando baixo grau de aproveitamento. O processamento mais comum, utilizado na maior parte das empresas, é o corte em chapas que posteriormente são lixadas, polidas e tingidas em diversas cores. Entre as empresas pesquisadas no presente estudo apenas uma já utiliza processos envolvendo novas tecnologias. Pode-se afirmar que a pesquisa e estudos que auxiliem em um melhor aproveitamento do material ágata possam representar novas oportunidades de produção de objetos e adornos pessoais (jóias) modificando um cenário onde o design inovador é pouco explorado e apresentado. A metodologia empregada para a realização deste estudo contemplou etapas de conhecimento da realidade dos locais de extração, beneficiamento e comercialização de ágata, avaliação dos processos, ensaio de usinagem convencional CNC, ensaios de usinagem não convencional por jato d’água CNC e desenvolvimento de produtos em formas complexas. Foram realizados vinte e quatro ensaios de usinagem, a análise posterior identifica larguras e espessuras ideais buscando a otimização da matéria-prima. Desta forma foi possível alcançar o objetivo principal nesta pesquisa de realizar o corte de ágata com utilização de tecnologia CNC em peças com formas complexas.Rio Grande do Sul State, Brazil, has important regions of extraction and processing of agate. Salto Jacuí Mining District, in the central region of this State, is one of the largest and more importante agate’s mines region of Brazil and even of the World. In Soledade town, there are the most important gemstone processing and trade companies of this State. Despite the abundance of gem materials, most of the objects produced in the different companies are very similar and have in common that they seldom are manufactured using new technological processes. Agate is usually exported as raw material or as cut polished slabs which can be dyed in various colors. Among several companies studied in this research, only one uses industrial processes involving new technologies. So, scientifical studies to indicate a better use of agate produced in Rio Grande do Sul, can provide new opportunities for the production of objects and personal ornaments (jewelry), modifying the trade where innovative designs are little explored. The methodology used in this study had several steps: identification of the extraction, processing and trade places of agate; evaluation of the industrial benefit processes used in agate; testing of conventional CNC machining on agate slabs; and testing on agate slabs of non-conventional computer controled machining by water jet cutting (WJC), with development of complex forms agate products. Twenty-four machining tests were carried out, with further analysis identifying ideal widths and thicknesses to optimize the use of agate raw material. With these tests, it was possible to achieve the goal of this study, which is to cut agate using water jet technology, in order to produce agate objects with complex forms.
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Morandeau, Antoine. "Méthodologie de caractérisation et de conception d'un outil coupant à plaquettes amovibles pour l'usinage de matériaux composites aéronautiques : Application aux opérations de surfaçage." Thesis, Tours, 2012. http://www.theses.fr/2012TOUR4041/document.
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Les composites utilisés dans l'industrie aéronautique sont hétérogènes. Ils sont composés d'une matrice polymère souple et ductile et d'un renfort dur et fragile. Les différentes phases ainsi que l'anisotropie du matériau peuvent rendre l'usinage de ces matières, difficile. Deux problèmes majeurs peuvent être rencontrés lors de l'usinage : garder l'intégrité de la matière usinée et réduire l'usure de l'outil de coupe. Les niveaux de qualité demandés dans le secteur aéronautique imposent une coupe sans défaut, ces derniers pouvant entrainer une altération ultérieure de la pièce. Les principaux défauts rencontrés sont : le délaminage des plis, la surchauffe de la résine, les plis non coupés francs ou l'écaillageAeronautic composites are inhomogeneous and most often consist in two distinctly phases. The reinforcement fibres are relatively hard and brittle whereas the matrix is soft and ductile. The anisotropy causes some severe challenges when machining composites. People in the field often experience a trade-off between two main problems ; on one hand, keeping the composite parts integrity and quality, and on the other hand, reducing the wear of the cutting tools. The quality level required in aeronautic applications imposes a high quality cut of machined parts. Common defects that may occur during machining of these materials are delamination, overheat of the resin, uncut fibres, and fibre pull-out
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Brlica, Vlastimil. "Technologické aspekty nástrojů pro obrábění dřeva." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229130.
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The fully fashioned master’s thesis within the frame of the master’s study at the Fakulty of mechanical engineering deals with subject woodworking tools. There are characteristics of wood and tool materials used for woodworking. There is an emphasis on milling cutter in each case of construction of selected woodworking tools. Whereas there is concrete proposal of milling cutter used for production of half round profile – half round concave cutter – at the end of the thesis.
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Machalová, Veronika. "Řezné síly při frézování vláknově vyztužených kompozitů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227947.
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Cutting forces problems analyses during milling operation, description of experimental machinery for measuring cutting forces. Characteristic of composite materials, their properties, production and usage. Evaluation of experimentally measured values of cutting forces during cylindrical conventional milling. Technical economic evaluation.
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Silveira, Flávia Lopes da. "Uso de usinagem por jato de água, usinagem por controle numérico computadorizado e corte a laser no design de superfícies tácteis a partir de padrões modulares encaixáveis em ágata e cedro." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/38946.
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Este trabalho tem por objetivo o design e a fabricação de superfícies tácteis a partir de padrões modulares encaixáveis. Estas superfícies foram construídas em diferentes materiais naturais (minerais e madeiras) e em distintos processos de fabricação inovadores (usinagem por jato de água, usinagem por controle numérico computadorizado ou CNC e corte a laser). A intenção foi desenvolver uma metodologia de design & tecnologia para aplicá-la em painéis de revestimento que possam ser produzidos em baixa escala de forma semi-industrial. A grande variedade de materiais naturais encontrados no estado do Rio Grande do Sul; a carência de design associado a estes materiais quando do produto final e o volume de rejeitos oriundos deste beneficiamento, foram os principais motivadores para a utilização destas matérias primas. O estudo de diferentes técnicas de design de superfície auxilia na transformação destes materiais, para que os mesmos passem a ter o formato de módulo. Dentro deste contexto, foram estudadas as técnicas desenvolvidas pelo artista Maurits Cornelis Escher. Ele dedicou boa parte de sua vida profissional à composição de desenhos que, justamente, partem da utilização da simetria, modularidade, continuidade e encaixe. Neste sentido, após a compreensão das técnicas utilizadas por Escher, alguns de seus desenhos foram aplicados nos materiais selecionados através dos processos de fabricação adequados, possibilitando a construção das diferentes superfícies tácteis. Os resultados obtidos identificam que a utilização de processos de fabricação inovadores para interferência nos materiais naturais são ferramentas importantes para a promoção de uma nova geração de produtos locais. Conclui-se que estas interferências viabilizam a fabricação de produtos com maior valor estético, social e econômico.This work aims at the design and the manufacturing of tactile surfaces from modular plug patterns. These surfaces were built in different natural materials (mineral and wood) and in distinct innovative manufacturing processes (waterjet machining, computerized numerical control machining or CNC and laser cutting). The objective was to develop a design & technology methodology for applying it in coating panels that can be produced on a semiindustrial small scale. The huge variety of natural materials found in Rio Grande do Sul State, the lack of design associated to these materials as to the final product and the volume of waste from this processing were the main motivators for the use of these raw materials. The study of these different techniques of surface design helps the transformation of these materials in order that they start to have the modular format. Within this context, the techniques developed by the artist Maurits Cornelis Escher were studied. He devoted much of his professional life to the composition of drawings beginning exactly with the use of symmetry, modularity continuity and joint. In this sense, after understanding the techniques used by Escher, some of his drawings were applied in the materials selected through suitable manufacturing processes, enabling the construction of different tactile surfaces. The results obtained identify that the utilization of innovative manufacturing processes to interfere in the natural materials are important tools for the promotion of a new generation of local products. It is conclude that these interferences enable the manufacture of products with greater aesthetic, social and economic value.
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Aytekin, Kasim. "Characterization of machinability in lead-free brass alloys." Thesis, KTH, Materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-240107.
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Ny lagstiftning har lagt fokus på den tociska naturen av bly som legeringselement I mässingsprodukter. Vattenförsörjningssystem är av största oro där misstänkt blyläckage från mässingsprodukter hotar människors hälsa, världen över. Denna studie har utförts i syfte att karaktärisera bearbetbarheten av blyfria mässingslegeringar för att förse industrin med nödvändig information och underlätta att ersätta dagens blyade alternativ. Karaktäriseringen har fokuserat på två specifika bearbetningsprocesser, nämligen svarvning och borrning där intresset har legat hos skärkraftsgenerering och spånbildning. Svarvtesterna riktade sig mot att jämföra tre olika legeringar, CW511L, AquaNordicÒ och CW625N. De två förstnämnda är blyfria och CW625N är en medelblyhaltig mässingslegering. Borrtesterna riktade sig mot att karaktärisera vilken effekt borrgeometrier har på skärkraftsgenerering och spånbildning. Huvudfokus lades på inverkan av spånvinkel och borrdiameter. Borrtesterna utfördes endast på AquaNordicÒ. Resultaten har visat att, signifikant högre skärkrafter genereras vid svarvning av blyfria legeringar jämfört med blyfria. Det fanns emellertid ingen signifikant skillnad mellan de båda blyfria legeringarna avseende skärkrafter, medan spånbildning förbättrades för AquaNordicÒ . Borrtesterna har å andra sidan visat att bearbetningen hos den blyfria AquaNordicÒ -legeringen kan förbättras genom att öka på spånvinkeln och minska borrdiameter. Baserat på resultaten från det här avhandlingsarbetet har man dragit slutsatsen att bearbetningen av blyfria mässingslegeringar är tillräckligt bra för att kunna antas av industrin. Förbättring är dock nödvändig för att ersätta de blyeade alternativen helt.Recent legislation has put focus on the toxic nature of lead as an alloying element in brass products. Watersupply systems are of biggest concern where suspected lead leakages from brass products are threatening human health. A comprehensive study has been conducted in order to characterize the machinability of lead-free brass alloys to provide the industry with necessary information to assist a replacement of the leaded alternatives. The characterization has focused on two particular machining processes, namely turning and drilling and has been based on cutting force generation and chip formation. While the turning tests aimed to characterize the machinability by comparing two lead-free alloys (CW511L and AquaNordic®) with a leaded alloy (CW625N), drilling tests aimed to characterize machinability of the lead-free AquaNordic® alloy particularly, with the main focus put on the impact of tool geometry on machinability. The results have shown that significantly higher cutting forces are generated during turning of lead-free alloys as compared to the leaded. There was, however, no significant difference between the two lead-free alloys regarding cutting forces while chip formation is improved for AquaNordic®. Drilling tests have shown that the machinability of the lead-free AquaNordic® alloy can be improved by increasing the tool rake angle and decreasing tool diameter. Based on the results from this thesis work, it has been concluded that the machinability of lead-free brass alloys is sufficiently good to be able to be adopted by the industry. However, improvement is necessary inorder to fulfill the requirement needed to replace the leaded alternatives.
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Dvořák, Jakub. "Zdokonalení technologie výroby součásti typu příruba." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402564.
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This diploma thesis focuses on improvement of the existing technology of the flange part in cooperation with the company Znojemské strojírny, s r.o. The theoretical part describes the technologies used in machining of the component. Subsequently, cutting materials and aluminum alloys are dealt with. A detailed analysis of the existing technology is performed in the practical part of the thesis followed by rationalization of the production process, which was carried out with respect to time and financial savings. A new technological procedure is developed after the improvement of the current production process. Finally, a technical-economic evaluation of the design improvement process is carried out.
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Ezeddini, Sonia. "Optimisation de l'usinage par le procédé d'électroérosion à fil des alliages de titane et des matériaux composites à base de titane appliqués à l'aéronautique." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC105.
Full textAbstract:
L’usinage par électroérosion est un procédé d’enlèvement de matière par fusion, vaporisation et érosion, réservé aux matériaux conducteurs et semi-conducteurs.Il peut être utilisé pour usiner les métaux et alliages, les aciers trempés, les alliages céramiques, les carbures métalliques, certaines céramiques et même des matériaux plus durs tels que le diamant polycristallin. La pièce ainsi chauffée voit ses caractéristiques mécaniques chuter et modifier, ce qui augmente son usinabilité. Les travaux réalisés ont porté sur l'influence de l'usinage par électroérosion à fil sur; l'intégrité de surface, l'usinabilité, la productivité et la précision de procédé, de plusieurs matériaux, tels que, le titane pur, l'alliage de titane Ti-6Al-4V, le composite intermétallique à base Ti-Al, le composite Ti17 et le composite Ti6242.En usinage par électro-érosion à fil, et plus précisément en finition, le procédé est caractérisé par un débit de matière, une largeur de kerf, un durcissement superficiel, une zone affectée thermiquement et un état de surface variant en fonction de plusieurs paramètres tels que, le courant de décharge, le temps d’impulsion, la tension d’amorçage, la vitesse de coupe, la pression d'injection de lubrifiant et la tension de fil.Toutefois, il s’agit d’une étude d’optimisation et de modélisation empirique des conditions de coupe des matériaux composites à base métallique et des alliages de titane, afin de maitriser et d'améliorer l'intégrité de surface usinée, d'augmenter la productivité et de perfectionner la précision du procédé. Par la suite, atteindre les exigences de la qualité et de la sûreté de fonctionnement des pièces aéronautiques.Dans cette étude, on a utilisé des méthodes de type Plan d'expériences, méthode de Taguchi et la Méthodologie des surfaces de réponses pour le calage et le contrôle des paramètres de l’usinage par électroérosion à fil, et ses conditions opératoiresEDM machining is a process for the removal of material by melting, spraying and erosion, which is reserved for conductive and semiconductor materials.It can be used for machining metals and alloys, hardened steels, ceramic alloys, metal carbides, some ceramics and even harder materials such as polycrystalline diamond. The heated part has its mechanical characteristics drop, which increases its machinability. The work carried out focused on the influence of WEDM machining on surface integrity, machinability, productivity and process precision, of several materials: pure titanium, Ti6Al4V alloy, composite intermetallicTi-Al based, Ti17 composite and Ti6242 composite.In ripping, and more precisely in finishing, the process is characterized by a flow of material,kerf width, surface hardening, heat affected zone and surface condition varying with discharge current, pulse time and voltage, cutting speed, lubricant injection pressure and wire tension.In fact, the machining conditions of metal-based composite materials and titanium alloys have been modeled and optimized to improve machined surface integrity, increase productivity, and improve process accuracy. Subsequently, meet the quality and safety requirements of aeronautical parts.Methods such as Experimental Design, Taguchi and Surface of Response were used for calibration and process control parameters and operating conditions
43
Freemantle, Christopher Stuart. "The wear studies of boron suboxide based cutting tool materials in machining applications." Thesis, 2010. http://hdl.handle.net/10539/8698.
Full textAbstract:
The wear characteristics of the first generation of boron suboxide (B6O) based
cutting tool materials fabricated from spark plasma sintered B6O/Y2O3/Al2O3
material have been investigated in terms of chemical and abrasive wear when
machining compacted graphite cast iron (CGI).
Static interaction diffusion couple experiments were conducted at
temperatures ranging from 700°C to 1300°C in order to simulate the chemical
interaction between the tool material (B6O) and the workpiece material (CGI).
The samples were studied using optical microscopy, scanning electron
microscopy (SEM) and energy dispersive x-ray spectrometry (EDS) as well as
x-ray diffraction (XRD) in order to identify the microstructural and
compositional changes as well as determine resulting phases. Interactions
observed below 900°C were found to be minimal, with significant chemical
interactions occurring at 1100°C and above. Iron boride phases were seen to
evolve at the interface of the tool and workpiece materials. Silicon diffusion
has been identified as a rapidly diffusing constituent with a tendency to diffuse
towards the interface. Due to the formation of various chemical products
during the experiments, chemical wear is expected to affect B6O tools at
expected machining temperatures.
Resistance to oxidation of B6O based materials was examined at 1000°C,
revealing a tendency for formation of boric acids on the surface of the material
in response to B2O3 formation and reaction with atmospheric moisture.
Evaporation of boric acids has been observed to result in a mass loss of the
material along with boric acid product crystal formation upon cooling.
Turning tests have revealed that the first generation of B6O based cutting tools
perform comparably with PcBN at very low cutting speeds, but suffer severe
abrasive wear as the cutting speed is increased, due to the need for
improvements in tool fabrication and the reduction of material damage and a
heat affected zone resulting from laser cutting.
Ultrahigh pressure sintered B6O based material was produced but was found to
possess a poor microstructure.
Computational thermodynamics and phase diagram generation has been
successfully compared to experimental results in predicting reaction products
and chemical behaviour of the tool materials at machining temperatures.
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Ko, Shun-Kai, and 柯舜凱. "Cutting mechanics, tool wear and surface integrity following routing of CFRP composite materials." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/69ktgz.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
106
Carbon fiber-reinforced plastic (CFRP) composite materials are increasingly used in the modern aircraft industry due to their superior specific strength and elastic modulus. Routing is one of the key process for shaping and trimming CFRP workpiece materials. However, the dimension accuracy and material integrity are very challenging to maintain owing to the anisotropic and inhomogeneous natures in the composites. In this work, cutting forces were modeled with the considerations of the cutting edge geometry and the associated angles in the analytical equations for the orthogonal and oblique cutting. Experimental works were conducted by using diamond-coated tools with the designs of the straight, nicked-helical and cross flutes, under the cutting speed (93.75-120 m/min) and feed rate (0.4-0.52 mm/rev) for the evaluations of the cutting force, tool wear, machined surface roughness and alternation of the microstructure. Statistical methods of the main effect plots and ANOVA are used for the analysis of significance of the operating parameters. Whereas the established force modeled were validated by the experimental results with the least errors (R2: ~99.08%). When Cutting speed 120 m/min and feed rate 0.52 mm/rev are employed, the utilization of straight flute routers resulted in the highest cutting force of 403.9 N, surface roughness of Ra~1.00 μm and tool flank wear of VB 52.2 μm whilst the nicked helix flutes routers produced lower cutting force (189.2 N) and tool flank wear (25.08 μm) with surface roughness 2.49 μm. Progression of the tool wear (VB value) is quantitatively demonstrated with the corresponding flank wear patterns. Scanned 3D topography and surface roughness in the machined surface are presented and discussed.
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FU, CHEN-CHE, and 傅振哲. "Design Plasma Composite Milling Cutter and Study of Heat - Assisted Processing for Difficult - to - machining Materials." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/43936d.
Full textAbstract:
碩士國立雲林科技大學
機械工程系
107
In the current aerospace industry, when processing high-nickel-based components such as Inconel 718, the processing conditions become very severe due to the high-temperature strength characteristics of the workpiece materials, resulting in serious tool loss, which in turn affects the processing quality and efficiency. Reducing the strength of the material and reducing the cutting force by heat assisting can effectively solve the above problems. At present, the heat-assisted heat source studied at home and abroad uses the laser as the main axis. However, the high cost of the laser and the use of the combination of the tool and the optical are complicated, which affects the commercialized niche. Therefore, this study proposes a new type of plasma-assisted milling combined machining mechanism, which integrates the discharge electrode and the tool into the face milling (ψ50mm, 3-piece) tool holder, and softens the workpiece by the plasma heat energy discharged by the high-voltage power supply. the goal of. In the early stage of the study, the simulation experiment of the discharge phenomenon of plasma was observed. The static plasma observation was used to change the distance between the electrode and the workpiece and change the wattage of the plasma to observe the mode of plasma discharge, electrode consumption and temperature change. This is followed by a self-designed dynamic simulation tool that loads the electrodes into the simulated tool and sets different processing parameters to observe the plasma changes during the rotation. In the middle of the study, a three-blade milling cutter was used to test the plasma compound milling experiment, in which the electrode material and the plasma power supply over-current method were continuously improved, and the image discharge device was used to record the plasma discharge process under the milling mechanism, or the milling process was not performed. Empty running simply observes the discharge behavior of the plasma discharge. In the course of the experiment, the results are recorded and analyzed in detail. As a reference for the final new tool design, the new tool is tested on the machine. In the later stage of the study, the self-designed double-edged double electrode was used to test the plasma compound milling experiment. The experimental results of the re-cutting showed obvious discharge phenomenon. Finally, on the double-edged and double-electrode tool, the plasma was completely discussed in various power distribution. The various plasma discharge phenomena exhibited by the different ways and processing positions.
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Parker, Grant. "Self-propelled rotary tool for turning difficult-to-cut materials." Thesis, 2011. http://hdl.handle.net/10155/249.
Full textAbstract:
Hard turning of difficult-to-cut materials is an economical method of machining components with high surface quality and mechanical performance. Conventionally in the machining industry, generating a component from raw goods includes a casting or forging process, rough machining, heat treatment to a desired hardness, and then finished-machining through a grinding process. Given the relative disadvantages of grinding, which include high specific energy consumption and low material removal rates, a newer technology has been introduced; hard turning. After the heat treatment of a cast part (generally in a range of 50-65 HRC), hard turning allows for immediate finished-machining. Hard turning reduces the production time, sequence, cost, and energy consumed. In addition, dry machining offsets environmental concerns associated with the use of coolant in grinding operations as well as other common turning operations.
Higher specific forces and temperatures in the contact area between the tool and workpiece lead to excessive tool wear. Generated tool wear affects the quality of the machined surface. Therefore, minimizing tool wear and consequently the generated surface quality become the status quo. Adverse effects associated with generated heat at the tool tip can be reduced by using
cutting fluid or by continuously providing a fresh cutting edge. The latter method will be applied in this thesis.
Rotary tool cutting involves a tool in the form of a disk that rotates about its axis. Different types of rotary tools have been developed, all with similar functional characteristics, however few are commercially available. Rotary tools can be classified as either driven or self-propelled. The former is provided rotational motion by an external source while the latter is rotated by the chip flow over the rake face of the tool.
A prototype self-propelled rotary tool (SPRT) for hard turning was developed which provides economical benefits and affordability for the user. It was tested on a turret-type CNC lathe by machining AISI 4140 Steel that was heat treated to 54-56HRC and Grade 5 Titanium (Ti-6Al-4V). Carbide inserts with ISO designation RCMT 09 T3 00 (9.5mm diameter) were used during machining. Both the SPRT rotational speed and the workpiece surface roughness were measured. Also, chips were collected and analyzed for each of the cutting conditions. The same procedure was followed during machining with the same tool which was denied the ability to rotate, therefore simulating a fixed tool with identical cutting conditions. Comparisons were made between tool life, surface roughness, and chip formation for the fixed tool and SPRT. Tool rotational speed was also analyzed for the SPRT. In general, the designed and prototyped SPRT showed very good performance and validated the advantages of self-propelled rotary tools.
A typical automotive component that is hard turned from difficult-to-cut materials is a transmission input shaft. These components demand high strength and wear resistance as they couple the vehicle‟s engine power to the transmission and remaining driveline.UOIT
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(10702884), Mohammed Naziru Issahaq. "HYBRID CUTTING EXTRUSION OF COMMERCIALLY PURE ALUMINUM ALLOYS." Thesis, 2021.
Find full textAbstract:
Commercial sheets, strips and wires are currently produced from aluminum alloys by multi-step deformation processing involving rolling and drawing. These processes typically require 10 to 20 steps of deformation, since the plastic strain or reduction that can be imposed in a single step is limited by material workability and process mechanics. In this work, a fundamentally different, single-step approach is demonstrated for producing these aluminum products using machining-based deformation that also enables higher material workability in the formed product. Two process routes are proposed: 1) chip formation by Free Machining (FM), and 2) constrained chip formation by Hybrid Cutting Extrusion (HCE).
Using the very soft and highly ductile commercially pure aluminum alloys as representative systems, various material flow transitions in response to the concentrated shear deformation are observed in FM including plastic instabilities. The flow instabilities usually manifested as folds of varying amplitudes on the unconstrained surface of the chips, are features that limit the desirability of the chip and potential use for strip applications. To suppress these instabilities, two strategies both involving deformation geometry design are outlined: 1) By using large positive rake angle, the flow can be transformed to be more laminar and thus reduces to a substantial amount, the flow instabilities. This also makes it possible for light rolling/drawing reductions to be adopted to smoothen the residual surface folds to improve the strip finish. 2) By using a constraining tool coupled with the cutting tool in what is referred to as HCE, the initial instability that leads to plastic buckling of the material is suppressed, thereby making the flow laminar and thus improve the quality of the strips.
Key property attributes of the chips produced by the shear-based deformation processes such as improved mechanical properties and in the case of HCE, superior surface finish compared to conventional processes of rolling/drawing are highlighted. Implications for commercial manufacture of sheet, strip and wire products are discussed.