Dissertations / Theses on the topic 'Tool deposition'
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1
Haberer, Elaine D. (Elaine Denise) 1975. "Particle generation in a chemical vapor deposition/plasma-enhanced chemical vapor deposition interlayer dielectric tool." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/8992.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.Includes bibliographical references (p. 77-79).
The interlayer dielectric plays an important role in multilevel integration. Material choice, processing, and contamination greatly impact the performance of the layer. In this study, particle generation, deposition, and adhesion mechanisms are reviewed. In particular, four important sources of interlayer dielectric particle contamination were investigated: the cleanroom environment, improper wafer handling, the backside of the wafer, and microarcing during process.
by Elaine D. Haberer.
S.M.
2
Connors, Sean Thomas. "Laser engineered net shaping deposition of M2 tool steel with Niobium additions." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406710485.
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Yang, Yu. "On-line inspection and thermal properties comparison for laser deposition process." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Yang_09007dcc803bca12.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 6, 2007) Includes bibliographical references.
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Nasuf, Gulfem Ipek. "Carbon nanotube growth on tool steel substrates by thermal chemical vapor deposition (CVD) /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1559857141&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Thesis (M.S.)--Southern Illinois University Carbondale, 2008."Department of Mechanical Engineering and Energy Processes." Includes bibliographical references (pages 117-119). Also available online.
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Bao, Yaxin. "Mechanical properties and microstructure study for direct metal deposition of titanium alloy and tool steel." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Bao_09007dcc803c0daf.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 29, 2007) Includes bibliographical references.
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Abd, Rahman M. N. "Modelling of physical vapour deposition (PVD) process on cutting tool using response surface methodology (RSM)." Thesis, Coventry University, 2009. http://curve.coventry.ac.uk/open/items/cca436cf-b72b-c899-ef02-bd522b0d7ec5/1.
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The Physical Vapour Deposition (PVD) magnetron sputtering process is one of the widely used techniques for depositing thin film coatings on substrates for various applications such as integrated circuit fabrication, decorative coatings, and hard coatings for tooling. In the area of coatings on cutting tools, tool life can be improved drastically with the application of hard coatings. Application of coatings on cutting tools for various machining techniques, such as continuous and interrupted cutting, requires different coating characteristics, these being highly dependent on the process parameters under which they were formed. To efficiently optimise and customise the deposited coating characteristics, PVD process modelling using RSM methodology was proposed. The aim of this research is to develop a PVD magnetron sputtering process model which can predict the relationship between the process input parameters and resultant coating characteristics and performance. Response Surface Methodology (RSM) was used, this being one of the most practical and cost effective techniques to develop a process model. Even though RSM has been used for the optimisation of the sputtering process, published RSM modelling work on the application of hard coating process on cutting tool is lacking. This research investigated the deposition of TiAlN coatings onto tungsten carbide cutting tool inserts using PVD magnetron sputtering process. The input parameters evaluated were substrate temperature, substrate bias voltage, and sputtering power; the out put responses being coating hardness, coating roughness, and flank wear (coating performance). In addition to that, coating microstructures were investigated to explain the behaviour of the developed model. Coating microstructural phenomena assessed were; crystallite grain size, XRD peak intensity ratio I111/I200 and atomic number percentage ratio of Al/Ti. Design Expert 7.0.3 software was used for the RSM analysis. Three process models (hardness, roughness, performance) were successfully developed and validated. The modelling validation runs were within the 90% prediction interval of the developed models and their residual errors compared to the predicted values were less than 10%. The models were also qualitatively validated by justifying the behaviour of the output responses (hardness, roughness, and flank wear) and microstructures (Al/Ti ratio, crystallographic peak ratio I111/1200, and grain size) with respect to the variation of the input variables based on the published work by researchers and practitioners in this field. The significant parameters that influenced the coating hardness, roughness, and performance (flank wear) were also identified. Coating hardness was influenced by the substrate bias voltage, sputtering power, and substrate temperature; coating roughness was influenced by sputtering power and substrate bias; and coating performance was influenced by substrate bias. The analysis also discovered that there was a significant interaction between the substrate temperature and the sputtering power which significantly influenced coating hardness, roughness, and performance; this interaction phenomenon has not been reported in previously published literature. The correlation study between coating characteristics, microstructures and the coating performance (flank wear) suggested that the coating performance correlated most significantly to the coating hardness with Pearson coefficient of determination value (R2) of 0.7311. The study also suggested some correlation between coating performance with atomic percentage ratio of Al/Ti and grain size with R2 value of 0.4762 and 0.4109 respectively.
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Madugula, Sashi Kiran. "Development of a Numerical Tool to Optimise the Infill Structure of Part Produced by Fused Deposition Modeling." Thesis, Troyes, 2022. http://www.theses.fr/2022TROY0002.
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L'objectif de cette thèse est de développer un outil numérique pour optimiser la structure interne des pièces imprimées en 3D produites par le procédé dépôt de fil fondu (DFF). En impression 3D, le terme remplissage fait référence à la structure interne de la pièce. Pour créer la conception de remplissage, un logiciel de tranchage est utilisé, qui crée généralement le remplissage uniformément dans toute la pièce. Lorsqu'une telle pièce est soumise à une charge externe, toutes les régions de remplissage ne subiront pas la même quantité de contrainte. Par conséquent, l'utilisation d'un remplissage uniforme dans toute la pièce n'est pas la solution la plus optimisée en termes d'utilisation des matériaux. Nous visons à développer un outil numérique pour faire évoluer la conception du remplissage par rapport aux contraintes mécaniques générées par les charges externes. Pour y parvenir, nous proposons deux méthodologies différentes basées sur un processus itératif utilisant des techniques de raffinement et de remaillage couplées à la simulation par éléments finis (simulation EF) pour contrôler la structure interne de la pièce sans modifier le contour. Ces méthodologies visent à renforcer le remplissage de la pièce sans modifier le contour, dans la zone où la résistance mécanique doit être améliorée pour renforcer la structure, mais aussi à diminuer la quantité de matière pour réduire le temps d'impressionThe objective of this thesis is to develop a numerical tool to optimise the internal structure of 3D printed parts produced by the Fused Deposition Modelling (FDM) process. In 3D printing, the term infill refers to the internal structure of the part. To create the infill design, slicing software is used, which generally creates the infill uniformly throughout the part. When such a part is subjected to external loading, not all the infill regions will experience the same amount of stress. Therefore, using uniform infill throughout the part is not the most optimised solution in terms of material usage. We aim to develop a numerical tool to evolve the infill design with respect to the mechanical stresses generated by the external loads. To achieve this, we propose two different methodologies based on an iterative process using refinement technique and remeshing techniques coupled to Finite Element simulation (FE simulation) to control the internal structure of the part without changing the contour. These methodologies aim to reinforce the infill of the part without changing the contour, in the area where the mechanical strength must be improved to strengthen the structure, but also to decrease the amount of material to reduce the printing time
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Gould, Parker Andrew. "Design, fabrication, and characterization of an ultra-low cost inductively-coupled plasma chemical vapor deposition tool for micro- and nanofabrication." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122561.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-232).
The high cost of semiconductor fabrication equipment has traditionally represented a large barrier to entry for groups seeking to develop or commercialize novel micro- and nanoscale devices. Much of the cost barrier stems from the large size of the substrates processed in this equipment, and the associated complexity of maintaining consistent operation across the full substrate area. By scaling the substrate size down from the 150-300 mm diameter sizes commonly seen in today's production environments, the capital cost and physical footprint of tools for micro- and nanoscale fabrication can be dramatically decreased, while still retaining a similarly high level of performance. In this work, an ultra-low cost inductively-coupled plasma chemical vapor deposition (ICPCVD) system for processing substrates up to 50.8 mm (2") in diameter is presented. The ICPCVD system is built within a modular vacuum tool architecture that allows sections of the full tool to be easily and inexpensively replaced to adapt to new processing conditions or provide additional functionality. The system uses a non-pyrophoric mixture of silane (1.5% in helium) and low substrate temperatures ( : 150*C) to deposit uniform silicon-based films with a high quality comparable to films deposited in research-grade commercial tools. Using response surface methods, the performance of the ICP-CVD system has been characterized for both silicon dioxide and silicon nitride films, and repeatable control of the deposited film properties, including deposition rate, index of refraction, film stress, and density, has been demonstrated.
by Parker Andrew Gould.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Blom, Ricky J. "Production and evaluation of rapid tooling for electric discharge machining using electroforming and spray metal deposition techniques." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16014/1/Ricky_Blom_Thesis.pdf.
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To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have
seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods.
The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes.
Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture.
The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings.
The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes.
The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable.
It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
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Blom, Ricky J. "Production and Evaluation of Rapid Tooling for Electric Discharge Machining using Electroforming and Spray Metal Deposition Techniques." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16014/.
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To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods. The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes. Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture. The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings. The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes. The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable. It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
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Sjöberg, Magnus. "The rotating injector as a tool for exploring DI diesel combustion and emissions formation processes." Doctoral thesis, KTH, Machine Design, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3208.
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A diesel fuel injector has been modified to allow rotationaround its axis, driven by an electric motor. Injections at upto 6000 rpm from the rotating injector have been investigatedunder the influence of air swirl on one optical research engineand one optically accessible heavy-duty diesel engine.
The experiments show that changing from a normal, staticinjection to a sweeping injection has profound effects on sprayformation, dispersion and penetration. This influences thefuel/air-mixing, autoignition, combustion rate and emissionsformation. The spray propagation is stronger influenced byinjector rotation than by air swirl.
The air entrainment into the spray increases forcounter-swirl rotation of the injector and this speeds up thevaporization and decreases the formation of soot. In addition,the oxidation of soot is enhanced since the counter-swirlinjection forces the intense fuel-rich and soot containingspray core to penetrate into fresh air instead of replenishingthe rich regions in the head of the spray. Fuel accumulationalong the piston bowl wall decreases as an effect of thereduced penetration with counter-swirl injection. Altogether,this decreases the smoke emissions for low and intermediateengine loads.
For the combustion system studied, counter-swirl rotation ofthe injector cannot decrease the smoke emissions at high engineload since the reduced spray penetration impairs the airutilization. Fast and efficient combustion at high loadrequires spray induced flame spread out into the squish region.Spray induced flow of cool fresh air from the bottom of thepiston bowl in towards the injector is also important for lowsoot formation rates.
Co-swirl rotation of the injector reduces the airentrainment into the spray and increases the soot formation.The increased smoke and CO emissions with co-swirl injectionare also attributed to the excessively large fuel-rich regionsbuilt up against the piston bowl wall.
Increased air swirl generally reduces smoke and COemissions. This is mainly an effect of enhanced burnout due tomore intense mixing after the end of fuel injection.
Changes in smoke as an effect of injector rotation aregenerally accompanied with opposite, but relatively small,changes in NO. Fast and efficient burnout is important for lowsmoke emissions and this raises both the temperature andproduction of NO. NO production is strongly influenced by thein-cylinder conditions during the latter part of themixing-controlled combustion and in the beginning of theburnout.
Keywords:diesel spray combustion, rotating injector,air swirl, air/fuel-mixing, soot, NO, CO, flame visualization,Chemkin modeling, soot deposition
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Schunemann, Esteban. "Paste deposition modelling : deconstructing the additive manufacturing process : development of novel multi-material tools and techniques for craft practitioners." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/13803.
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A novel paste deposition process was developed to widen the range of possible materials and applications. This experimental process developed an increasingly complex series of additive manufacturing machines, resulting in new combinations of novel materials and deposition paths without sacrificing many of the design freedoms inherit in the craft process. The investigation made use of open-source software together with an approach to programming user originated infill geometries to form structural parts, differing from the somewhat automated processing by 'closed' commercial RP systems. A series of experimental trials were conducted to test a range of candidate materials and machines which might be suitable for the PDM process. The combination of process and materials were trailed and validated using a series of themed case studies including medical, food industry and jewellery. Some of the object created great interest and even, in the case of the jewellery items, won awards. Further evidence of the commercial validity was evidenced through a collaborative partnership resulting in the development of a commercial version of the experimental system called Newton3D. A number of exciting potential future directions having been opened up by this project including silicone fabrics, bio material deposition and inclusive software development for user originated infills and structures.
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Hayagrivan, Vishal. "Additive manufacturing : Optimization of process parameters for fused filament fabrication." Thesis, KTH, Lättkonstruktioner, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-238184.
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An obstacle to the wide spread use of additive manufacturing (AM) is the difficulty in estimating the effects of process parameters on the mechanical properties of the manufactured part. The complex relationship between the geometry, parameters and mechanical properties makes it impractical to derive an analytical relationship and calls for the use of a numerical model. An approach to formulate a numerical model in developed in this thesis. The AM technique focused in this thesis is fused filament fabrication (FFF). A numerical model is developed by recreating FFF build process in a simulation environment. Machine instructions generated by a slicer to build a part is used to create a numerical model. The model acts as a basis to determine the effects of process parameters on the stiffness and the strength of a part. Determining the stiffness of the part is done by calculating the response of the model to a uniformly distributed load. The strength of the part depends on it's thermal history. The developed numerical model serves as a basis to implement models describing the relation between thermal history and strength. The developed model is suited to optimize FFF parameters as it encompass effects of all FFF parameters. A genetic algorithm is used to optimize the FFF parameters for minimum weight with a minimum stiffness constraint.Ett hinder för att additiv tillverkning (AT), eller ”3D-printing”, ska få ett bredare genomslag är svårigheten att uppskatta effekterna av processparametrar på den tillverkade produktens mekaniska prestanda. Det komplexa förhållandet mellan geometri och processparametrar gör det opraktiskt och komplicerat att härleda analytiska uttryck för att förutsäga de mekaniska egenskaperna. Alternativet är att istället använda numeriska modeller. Huvudsyftet med denna avhandling har därför varit att utveckla en numerisk modell som kan användas för att förutsäga de mekaniska egenskaperna för detaljer tillverkade genom AT. AT-tekniken som avses är inriktad på Fused Filament Fabrication (FFF). En numerisk modell har utvecklats genom att återskapa FFF-byggprocessen i en simuleringsmiljö. Instruktioner (skriven i GCode) som används för att bygga en detalj genom FFF har här översatts till en numerisk FE-modell. Modellen används sen för att bestämma effekterna av processparametrar på styvheten och styrkan hos den tillverkade detaljen. I detta arbete har strukturstyvheten hos olika detaljer beräknats genom att utvärdera modellens svar för jämnt fördelade belastningsfall. Styrkan, vilket är starkt beroende på den tillverkade detaljens termiska historia, har inte utvärderats. Den utvecklade numeriska modellen kan dock fungera som underlag för implementering av modeller som beskriver relationen mellan termisk historia och styrka. Den utvecklade modellen är anpassad för optimering av FFF-parametrar då den omfattar effekterna av alla FFF-parametrar. En genetisk algoritm har använts i detta arbete för att optimera parametrarna med avseende på vikt för en given strukturstyvhet.
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Craven, Adrian Lewis. "Studies of steered arc motion and macroparticle production in PVD processing." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19510/.
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During the past decade the production industry has constantly strived to improve performance and cut costs, this has been aided by the development of high performance tools. The advancement of these tools has been accomplished by the application of hard wearing, low friction, coatings. A key process in the production of such coatings is Physical Vapour Deposition (PVD). Interest in such thin films has led to much research effort, both academic and industrial, being devoted to the area. In order that these advancements in technology continue, research into the fundamental aspects of PVD is required. This thesis describes research and experimental studies which have been performed to study the effect of "steering" an electric arc on various aspects of its behaviour. "Steering" of the arc is achieved by applying external magnetic fields which allow the guidance of the path of the arc. Work by earlier authors has aimed to control the arc more fully. The research presented here is based of a novel electromagnetic three coil steering array of cylindrical geometry. With such coils it is possible to vary the field profiles to a greater degree than has been previously achieved, permitting a greater range of steering arrangements/fields to be applied. The research presented is divided into two distinct areas: Firstly a number of experiments were performed to assess the effectiveness of the new steering coils on the motion of the arc. A personal computer was used here along with new arc motion monitoring electronics. This enabled the simultaneous measurement of the orbital transit times and also the degree of travel perpendicular to the steered direction of motion of the arc, as it traversed the surface of the cathode. Such information was then used to produce values for standard deviation of the arc from its steered path, velocity of the arc and a diffusion constant related to the motion of the arc. Such values then allowed evaluation of the stochastic model of arc motion proposed by Care'. Secondly the effect of changes in magnetic field on the production, ejection angle and size of macroparticles(small molten droplets of the cathode material) was studied. This was accomplished by the design, production and usage of new sample holding equipment. This equipment allowed the coating of highly polished samples at a number of angles in relation to the cathode, with all samples being held equidistant from the arc track. Once such samples coatings had been produced they were then analysed using a Scanning Electron Microscope(SEM) to give macroparticle density figures.
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Dingremont, Norbert. "Analyse de la compatibilité des traitements de nitruration par voie ionique avec les dépôts par plaquage ionique : application à l'acier de construction 35NCD16 et à l'acier d'outillage pour travail à chaud Z38CDV5." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL110N.
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Afin de déterminer dans quelle mesure les traitements de nitruration par voie ionique peuvent être compatibles aves les dépôts par plaquage ionique, nous avons analysé l'influence de la procédure de dépôt sur la stabilité des couches nitrurées. Ce travail a permis de montrer que le cycle thermique associé à la procédure de dépôt peut conduire à lui seul à la déstabilisation des couches de combinaison et seulement celles-ci. Dans ce cas, la stabilité thermique intrinsèque des couches de combinaison est mise en cause. Nous avons également mis en évidence la déstabilisation de ces mêmes couches lors de la réalisation de l'étape de décapage ionique effectuée sous plasma d'argon seul et ce, pour des températures de dépôt relativement basse (400°C). Ce phénomène conduit à la dénitruration des couches de combinaison et à la formation d'une interphase ferritique qui est à l'origine des problèmes d'adhérence observés lors de l'élaboration de revêtements durs. L’introduction d'une pression partielle d'azote contrôlée dans le plasma d'argon au début de l'étape de décapage permet de contourner ce problème, elle met également en évidence la présence d'espèces nitrurantes dans le plasma. Cette constatation nous a permis d'envisager l'étude de la faisabilité des traitements de nitruration dans les installations de dépôt BALZERS. Celle-ci a conduit à la réalisation des traitements plurifonctionnels de nitruration et de dépôt dans une même installation d'une part, en raison des gains cinétiques observés au niveau du traitement thermochimique et d'autre part, en raison d'une meilleure adhérence du dépôt sur les couches nitrurées. En effet, la transition entre les deux traitements ne nécessite pas une remise à l'air de l'installation ce qui réduit considérablement les risques de contamination interfaciale couche nitrurée - revêtement. En second lieu, l'élévation des vitesses de nitruration, provenant d'une plus grande réactivité des faisceaux de plasma à haute densité de courant, a permis d'industrialiser de façon rentable ce nouveau procède de traitement plurifonctionnel
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Nováková, Radana. "Povlakování střižných nástrojů ze slinutých karbidů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231749.
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Tato diplomová práce se zabývá problematikou PVD povlakování střižných nástrojů ze slinutých karbidů, se zaměřením na zvýšení životnosti postupových nástrojů. Především poukazuje na využití povlakovaných nástrojů v praxi a procesních kroků před a po procesu povlakování. V teoretické části jsou popsány obě základní metody povlakování, tj. fyzikální metoda PVD a metoda CVD, založena na chemickém procesu. Dále jsou představeny jednotlivé způsoby vlastních procesů povlakování se stručným popisem výhod i nevýhod jejich využití. Praktická část je zaměřena na testování, jehož podstatou byl nejen vhodný výběr samotného povlaku pro daný materiál, ale i úpravy před a po povlakování, které jsou často opomínány. Ty jsou však nezbytnou součástí a mají výrazný vliv nejen na výsledný povlak, ale i na kvalitu pracovního procesu. Vyhodnocením experimentu je souhra určení nejproduktivnějšího povlaku v závislosti na dané úpravě.
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Chan, Yi-kei, and 陳伊祺. "Nutrient input of Tolo Harbour by river, atmospheric deposition and submarine groundwater discharge." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46732718.
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Cesur, Halil. "Development Of Cubic Boron Nitride (cbn) Coating Process For Cutting Tools." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610640/index.pdf.
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In today’
s market conditions, higher tool life and durable cutting tools which can stand high cutting speeds are required in chip removal process. In order to improve the performance of cutting tools, coatings are employed extensively. Cubic boron nitride (cBN) is a new kind of coating material for cutting tools due to its outstanding properties and testing of cBN as a hard coating for machining have been increasing in recent years. However, there are some challenges such as compressive residual stress, poor adhesion and limiting coating thickness during the deposition of cBN on substrates. In this study, cubic boron nitride (cBN) coatings are formed on cutting tools from hexagonal boron nitride (hBN) target plates. For this purpose, a physical vapor deposition (PVD) system is utilized. PVD system works on magnetron sputtering technique in which material transfer takes place from target plate to substrate surface. Firstly, cBN coatings are deposited on steel and silicon wafer substrates for measurements and analyses. Compositional, structural and mechanical measurements and analysis are performed for the characterization of coatings. Next, several types of cutting tools are coated by cBN and the effects of cBN coatings on cutting performance are investigated. Finally, it can be said that cubic boron nitride coatings are successfully formed on substrates and the improvement of wear resistance and machining performance of cBN coated cutting tools are observed.
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Xu, Zhenqing. "Synthesis, characterization, and applications of CVD micro- and nanocrystalline diamond thin films." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002077.
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Ren, Lan. "Integrated process planning for a hybrid manufacturing system." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Ren_09007dcc8046714a.pdf.
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Thesis (Ph. D.)--Missouri University of Science and Technology, 2008.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 18, 2008) Includes bibliographical references.
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Berg, Martin, and Albin Eriksson. "Toward predictive maintenance in surface treatment processes : A DMAIC case study at Seco Tools." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-84923.
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Surface treatments are often used in the manufacturing industry to change the surface of a product, including its related properties and functions. The occurrence of degradation and corrosion in surface treatment processes can lead to critical breakdowns over time. Critical breakdowns may impair the properties of the products and shorten their service life, which causes increased lead times or additional costs in the form of rework or scrapping. Prevention of critical breakdowns due to machine component failure requires a carefully selected maintenance policy. Predictive maintenance is used to anticipate equipment failures to allow for maintenance scheduling before component failure. Developing predictive maintenance policies for surface treatment processes is problematic due to the vast number of attributes to consider in modern surface treatment processes. The emergence of smart sensors and big data has led companies to pursue predictive maintenance. A company that strives for predictive maintenance of its surface treatment processes is Seco Tools in Fagersta. The purpose of this master's thesis has been to investigate the occurrence of critical breakdowns and failures in the machine components of the chemical vapor deposition and post-treatment wet blasting processes by mapping the interaction between its respective process variables and their impact on critical breakdowns. The work has been conducted as a Six Sigma project utilizing the problem-solving methodology DMAIC. Critical breakdowns were investigated combining principal component analysis (PCA), computational fluid dynamics (CFD), and statistical process control (SPC) to create an understanding of the failures in both processes. For both processes, two predictive solutions were created: one short-term solution utilizing existing dashboards and one long-term solution utilizing a PCA model and an Orthogonal Partial Least Squares (OPLS) regression model for batch statistical process control (BSPC). The short-term solutions were verified and implemented during the master's thesis at Seco Tools. Recommendations were given for future implementation of the long-term solutions. In this thesis, insights are shared regarding the applicability of OPLS and Partial Least Squares (PLS) regression models for batch monitoring of the CVD process. We also demonstrate that the prediction of a certain critical breakdown, clogging of the aluminum generator in the CVD process, can be accomplished through the use of SPC. For the wet blasting process, a PCA methodology is suggested to be effective for visualizing breakdowns.
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Cabrol, Elodie. "Étude et compréhension des mécanismes d'endommagement de surface de matrices de forgeage à chaud rechargées." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2015. http://www.theses.fr/2015EMAC0012.
Full textAbstract:
Dans le domaine du forgeage à chaud de pièces aéronautiques, les matrices en acier sont couramment rechargées, sur quelques millimètres d’épaisseur, par un alliage base cobalt (Stellite 21) déposé par procédé de soudage à l’arc (MIG). Dans le cadre de ce travail de thèse, ce rechargement « classique» est comparé à des rechargements Stellite 21 et Stellite 6 déposés par deux procédés émergents dans ce domaine, le PTA et le LASER. L’objectif est d’apporter des éléments de compréhension aux mécanismes d’endommagement de surface, notamment par écoulement plastique, de ces différents rechargements afin de dégager des voies d’amélioration pour augmenter la durée de vie des matrices. Pour cela, des essais tribologiques (semi-industriels et laboratoire) ont été mis en œuvre pour créer des endommagements de surface comparables à ceux observés sur matrices industrielles. Associées à ces essais, des investigations microstructurales, structurales et mécaniques multi-échelles ont été réalisées (traction, flexion, microdureté, MO, MEB, MEB-STEM, DRX, EBSD). Selon les couples « nuance/procédé » de rechargement, des mécanismes de déformation plastique par glissement des dislocations parfaites et par transformation de phase CFC en HC ont été identifiés. L’activation de ce dernier a pu être reliée à la température de transformation allotropique CFC/HC du cobalt. Cette température dépend à la fois (i) des éléments d’addition, variant en fonction de la nuance déposée (Cr, C,...), (ii) de la dilution (variation de la teneur en Fe) liée aux paramètres de soudage et (iii) du nombre de couches déposées. De plus, une influence significative de la transformation de phase sur l’évolution du coefficient de frottement a été mise en évidence. En effet, dans le cas où la transformation de phase n’est pas observée, le coefficient de frottement est stable durant l'essai alors qu'une chute de la courbe de coefficient de frottement a été reliée avec la transformation de phase CFC en HC. Parallèlement, l'écoulement plastique des dendrites est observé en extrême surface sur quelques dizaines de micromètre d'épaisseur dans la direction de glissement. Cet écoulement est associé à une forte texturation morphologique et cristallographique de la phase identifiée (CFC ou HC), avec une orientation des plans de plus grande densité atomique parallèlement à la surface de glissement. Les résultats montrent également que sous sollicitations tribologiques, un important durcissement est observé en surface (jusqu'à 90%) et une corrélation a pu être établie entre l'augmentation de la microdureté et le taux de déformation plastiqueIn the field of hot forging of aeronautical parts, the steel dies are commonly hardfaced, on few millimeters thick, by a cobalt-based alloy (Stellite 21) deposited by arc welding (MIG). As part of this thesis, this "classic" hardfacing is compared to Stellite 21 and Stellite 6 hardfacings deposited by two emerging processes in this area, the PTA and the LASER one. The objective is to assess surface damage mechanisms, especially induced by plastic strain, of these various hardfacings. Tribological tests (laboratory and semi-industrial) were used to create surface damage comparable to those observed in industrial dies. Associated with these tests, multiscale microstructural, structural and mechanical investigations have been performed (tensile, bending, microhardness, OM, SEM, STEM, XRD, EBSD). According to the « material/process » couple, plastic strain mechanisms by perfect dislocation glide and by FCC to HCP phase transformation have been identified. The activation of the latter has been connected to the temperature of the allotropic phase transformation (FCC/HCP) in cobalt. This temperature depends on (i) the alloying elements, varying according to the deposited grade (Cr, C, ...), (ii) the dilution (Fe content evolution) connected to the welding parameters and (iii) the number of deposited layer. Moreover, a significant influence of the phase transformation on the evolution of the friction coefficient has been evidenced. Indeed, if the phase transformation is not observed, the friction coefficient is stable during the test, while a drop of the friction coefficient curve is connected with the FCC to HCP phase transformation. Moreover, the plastic flow of dendrites is observed at the extreme surface, on a few tens of micrometres in thickness, in the direction of sliding. It is associated with a high morphologic and crystallographic texturing of the identified phase (FCC or HCP), with the highest atomic density planes mostly oriented parallel to the sliding surface. The results also show that, under tribological laodings, a significant hardening is observed on the surface (up to 90%) and a correlation has been established between the increase in the microhardness and the plastic deformation ratio
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Jivcov, Sandra [Verfasser], and Martin [Gutachter] Melles. "From Lake to Ocean: Disentangling past and present depositional processes and environmental conditions of sub-Antarctic South Georgia using molecular and isotopic tools / Sandra Jivcov ; Gutachter: Martin Melles." Köln : Universitäts- und Stadtbibliothek Köln, 2018. http://d-nb.info/1183255527/34.
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Júnior, Adonias Ribeiro Franco. "Obtenção de revestimentos dúplex por nitretação a plasma e PVD-TiN em aços ferramenta AISI D2 e AISI H13." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-02102003-114623/.
Full textAbstract:
No presente trabalho foi avaliado o efeito da microestrutura e da capacidade de suportar carregamento de camadas nitretadas produzidas em aços ferramenta AISI H13 e AISI D2 sobre a aderência e a resistência ao desgaste microabrasivo de revestimentos de TiN-PVD. Em cada um desses aços, foram produzidas camadas nitretadas de diferentes estruturas e espessuras, e foram determinadas experimentalmente as curvas potencial início de formação de camada branca, para a nitretação a 520oC. Para o aço ferramenta AISI H13, o emprego de tempos de pré-tratamento de nitretação mais prolongados ( aproximadamente 11 h) foi necessário para aprofundar a camada nitretada e, conseqüentemente, aumentar a capacidade de suportar carregamento dos revestimentos, evitando a formação de bordas que provocam o lascamento e a escamação das camadas de TiN. Observou-se que esse tipo de falha persiste se a zona de endurecimento for pouco profunda, uma vez que a transição de propriedades mecânicas da camada de TiN para o núcleo não nitretado continua abrupta e a capacidade de suportar carregamento da camada nitretada ainda é baixa. Por outro lado, curtos tempos de nitretação (aproximadamente 42 min.) foram suficientes para aumentar a aderência das camadas de TiN ao aço ferramenta D2, pois o núcleo não nitretado desse aço possui uma capacidade de suportar carregamento razoável. Observou-se que a resistência ao desgaste microabrasivo e a aderência dos revestimentos são prejudicadas com a presença de uma camada preta na interface camada de TiN/camada nitretada. Quando a superfície dos revestimentos é carregada, falhas do tipo casca de ovo facilmente ocorrem.In this work, the influence of both the microstructure and the load-bearing capacity of nitrided layers, formed on top of AISI D2 and AISI H13 tool steels, on adhesion and wear resistance of PVD-TiN coatings was studied. The threshold nitriding potential curves for the above mentioned steels and the optimum conditions of the pre-treatments which increased the adhesion as well as the wear resistance of the PVD-TiN were determined experimentally. By using longer nitriding times (about 11 h) and lower nitrogen contents in the gas mixture (about N2-5%vol.), it was possible to minimize the pile-up degree of the TiN/H13 nitrided substrates and, consequently, the occurrence of coatings chipping. This flaw persists when the nitrided layer is thin, due to an abrupt transition of mechanical properties at the TiN coating / steel core interface. Shorter nitriding times (about 42 min.) and lower nitrogen contents (about N2-5%vol.), on the other hand, are sufficient to guarantee a better adhesion of TiN coatings on AISI D2 tool steel, as the core of such steel possesses relatively better load-bearing capacity than the AISI H13 tool steel. The presence of a black layer at the TiN/nitrided layer interface was observed in all coatings deposited over nitrided layers produced above the threshold nitriding potential curves. This layer affects adversely the wear resistance and the adhesion of the TiN coatings. When higher loads are applied on the coated surface, egg shell type flaws easily occur.
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D'Ans, Pierre. "Contribution à la mise au point d'une démarche rationnelle de sélection des traitements de surface: illustration dans le cas des dispositifs de fonderie de l'aluminium." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210366.
Full textAbstract:
Sélectionner des traitements de surface pour l’industrie nécessite de prendre en compte :les propriétés à conférer au substrat, la nature et la géométrie de celui-ci et les caractéristiques du milieu extérieur. Certaines combinaisons de ces paramètres rendent difficile la sélection d’un traitement unique, d’où le recours à des multitraitements de surface. Dès lors, se posent les questions suivantes :- Utiliser des multitraitements de surface peut se faire en scindant les différentes requêtes en sous-ensembles, de manière à ce que chaque traitement réponde à l’un d’eux. Dans quel ordre ces requêtes doivent-elles être introduites par rapport au substrat ?
- Comment sélectionner les traitements de surface répondant à chaque requête individuelle ?
- Comment classer des multitraitements en termes d’adéquation au problème posé ?
Dans ce travail, les première et troisième questions sont abordées, en explorant les requêtes concernant habituellement les dispositifs de moulage de l’aluminium :
- Résistance aux contraintes d’origine thermique.
- Résistance à la corrosion par les métaux fondus.
- Résistance au frottement.
L’analyse de la bibliographie relative aux traitements de surface utilisés dans ces systèmes a été analysée et des « architectures »-types ont été identifiées (chapitre 3). On prévoit, par exemple, un traitement conférant la résistance à la fatigue superficielle, ainsi qu’un revêtement étanche et résistant à l’aluminium fondu. Une barrière thermique est parfois préconisée.
Pour chacune des architectures, des traitements de surface individuels peuvent être sélectionnés. Un « facteur de performance » permettant de classer les solutions par rapport au problème de la fatigue thermique a été construit (chapitre 4) et discuté dans deux situations :
- Lorsqu’un revêtement est présent, et que les contraintes d’origine thermique (différence de dilatation thermique couche-substrat) menacent de le rompre lors de l’immersion dans un milieu corrosif à haute température. Des essais de corrosion dans de l’aluminium fondu ont été réalisés sur un acier revêtu par du nitrure de chrome dopé à l’aluminium, synthétisé par déposition physique en phase vapeur (chapitre 5 – collaboration :Inasmet).
- Lorsque des variations thermiques rapides menacent de rompre le substrat et la (les) couches. Des essais de fatigue thermique ont été réalisés sur de l’acier à outils pour travail à chaud non traité, boruré ou recouvert d’un multitraitements (zircone yttriée / NiCrAlY / boruration / acier). Le revêtement en zircone yttriée a été obtenu par projection par plasma. L’essai de fatigue thermique a été modélisé et le facteur de performance, discuté (chapitre 6).
Au chapitre 7, les architectures-types ont été introduites dans une méthodologie de sélection des multi-traitements de surface, qui a été appliquée dans deux cas :
- Celui des moules de fonderie, devant résister à la fatigue thermique et à la corrosion par l’aluminium fondu. Le facteur de performance a été extrapolé à d’autres situations qu’aux chapitres 5 et 6. Les solutions habituellement proposées pour résoudre ce problème sont retrouvées.
- Celui de deux pièces en acier frottant l’une contre l’autre en présence d’aluminium fondu.
To select surface treatments, one must account for the required functional properties, the substrate features and the solicitations the substrate must endure. Certain combinations of these parameters make it difficult to select a single surface treatment, a reason why several successive treatments are preferred. To select them, one needs to determine:
- How to divide the several requests into groups and how to stack up these groups from the substrate to the outer surface, so that each treatment deals with one specific group of requests/properties.
- How to select individual layers for each group of properties.
- How to rank the multi-treatments in terms of relevance for a given application.
In this work, one tries to answer the first and the third questions, by studying the case of aluminium foundry, in which the industrial devices frequently face the following solicitations:
- Thermal stress (thermal fatigue, thermal expansion mismatch).
- Presence of corrosive molten metal.
- Sliding wear.
In the literature, several “standard” architectures are proposed (chapter 3), like a diffusion layer reducing superficial fatigue plus a corrosion barrier layer. A thermal barrier coating is also sometimes proposed.
For each of these architectures, one can select individual treatments. To rank them, one devised a “performance index” for thermal stress (chap.4), which is discussed for two cases:
- For large differences between layer and substrate thermal expansion coefficients, when both are put into contact with a high temperature corrosive medium, the layer may be damaged. One discusses this case by examining the corrosion caused by molten aluminium for a steel substrate coated by anticorrosive chromium nitride doped with aluminium. The layer is produced by physical vapour deposition (chap. 5 – cooperation: Inasmet).
- Repeated fast surface temperature transients can also damage the substrate and/or the layer by thermal fatigue. One conducted thermal fatigue tests with samples of hot work tool steel, respectively untreated, simply borided and protected by a multilayer. In the last case, top coat is yttria stabilised zirconia, followed by a nickel superalloy and then a borided layer (undercoat). One synthesized the zirconia coating by plasma spray and one modelled the thermal fatigue (chap. 6).
In chap. 7, architectures from chap. 2 are introduced in a multi-treatment selection routine, which is applied in two cases:
- Foundry moulds for molten aluminium, withstanding both thermal fatigue and corrosion. The devised performance index is extrapolated beyond the tests of chap. 5 and 6 to treatments for this industrial application, thereby quantifying their respective merits.
- A foundry device exposed to molten metal and sliding wear.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Chao, Yen-Lung, and 趙彥龍. "Sputtering Deposition of ZrWN Films to Enhance Milling Tool Performance." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/75295311513456092050.
Full textAbstract:
碩士龍華科技大學
機械工程系碩士班
103
Hard films own lower friction coefficient, high hardness, higher wear, corrosion resistance and excellent thermal stability, have been widely used to improve tools and machine parts. ZrWN thin films were deposited onto tungsten carbide tools and glass substrates, by direct current reactive magnetron co-sputter. The targets were Zr and W, Ar was the plasma gas and N2 was the reactive gas. An orthogonal array, the signal-to-noise ratio and analysis of variance are used to analyze the effect of the ZrWN film deposition parameters. Using the Taguchi method for design of a robust experiment, the main deposition parameters, such as DC power of sputtering (100, 200, 300 Watt), working pressure (6.5, 8, 15 mtorr), substrate plasma etching power (un-etching, 100, 200 Watt) and annealing temperature (as-deposited, 200, 400°C) were optimized. The surface morphologies and structural properties the film was determined by SEM. Dry milling of low carbon steel (S20C, 50×70 mm) tests was carried out with these coated and un-coated tools. It is found the shows the use of ZrWN films coated on the cutting tool remarkably decreases roughness and flank wear. In the confirmation runs, when using grey relational analysis, improvement of 35.5% was obtained in surface roughness and 41.6% in flank wear, respectively. In the study the performance characteristics of the ZrWN films are better than that the commercially available coating cutter.
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Kuo, Yi-Chen, and 郭益辰. "Gas thermal reactive deposition/diffusion of chromium on tool steels." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/92882433491547283346.
Full textAbstract:
碩士國立高雄應用科技大學
模具工程系碩士班
101
Gas thermal reactive diffusion / deposition (TRD) of chrome on SKD11 and ASP2030 tool steels were employed. Different chromizing temperatures of 950℃、900℃、850℃、800℃ and 750℃ with fixed 10 hours duration and nitriding pre-treatment were controlled to obtain various coatings thickness. Scanning electron microscope(SEM) and EDS mode was used to measure the coating thickness and then the activation energy and diffusion constant for each chromizing process were calculated. Hv hardness testing was applied to measure the Hv hardness variation with chromizing depth while the abrasion testing was used to examine the abrasion resistances for chromizing processes. The crystal structures of chromizing layers were also identified by X-ray diffraction (XRD). The results show that the chromizing layers for SKD11 are apparently higher than those of ASP2030. The chromizing layer for SKD11 steel with nitriding pre-treatment has the highest chromizing thickness of 20μm and compared to 13μm without nitriding while a small change occurs for ASP2030 with highest chromizing thickness of 9.5μm relative to 8μm. The activation energies are calculated by at least square method to be 147.47kJ/mol-1 and 106.09 kJ/mol-1 for SKD11 with and without nitriding pre-treatment while 118 kJ/mol-1 and 111 kJ/mol-1 for ASP2030, which indicate the effect of nitriding pre-treatment is obviously greater for SKD11 steel than ASP2030 steel. The highest Hv hardness of chromizing layer with and without nitriding pre-treatment steel are 1610Hv and 1700Hv while 1570Hv and 1860Hv for ASP2030 steel. The abrasion resistance for SKD11 steel with chromizing temperature greater than 850℃ appear obviously higher than that of substrate. All chromizing layers for ASP2030 without tempering after chromizing show the less abrasion resistance than that of substrate whereas the abrasion resistance for chromizing tempering greater than 850℃ with tempering after chromizing has better abrasion resistance than that of substrate. XRD indicate the crystal structures of the chromizing layers of SKD11 and ASP2030 steels for higher chromizing temperatures with nitriding pre-treatment are Cr2C and Cr2N while Cr2C without nitriding pre-treatment. The lower chromizing temperatures tend to result in Cr7C3 and CrN crystal phase with nitriding pre-treatment while Cr7C3 forms without nitriding pre-treatment.
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Harry and 陳俊欽. "The Deposition of Modified Diamond-Like Carbon Films on Tool steel." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/13312344855643796266.
Full textAbstract:
碩士國立成功大學
化學工程學系
87
Abstract Diamond-like carbon films have many excellent physical and chemical properties，and thus have high potentials in many industrial applications. However，diamond-like carbon films have been suffering from the large internal compressive stress and thermal instability. The large stress induces the poor adhesion of films to the substrates. The thermal instability reduces the service lifetime of the film. First, Ti nano clusters have been incorporated in the DLC films forming a composite film to enhance its toughness, hopefully not sacrificing much the hardness. TEM observation identified 6-70nm Ti clusters in the DLC film. Besides，HMDSO was employed to deposit the DLC films incorporating Si-O-Si functional groups. The Si-O groups are homogeneously distributed in the DLC films. And the film adhesion was greatly improved up to 50N. Raman spectra showed that the structure was unchanged after thermal treatments at 400℃ for 2hrs. Films adhesion of the SiO-Containing DLC/DLC was compared with that of the gradient TiN/TiC/DLC layers by scratching test. The critical load for the SiO-containing DLC/DLC gradient layer was 22.4N，very close to 24.3N for the TiN/TiC/DLC gradient layer. Finally, the film growth rate using HMDSO was slower than that using CH4，likely due to the sputtering of the film by the heavy HMDSO molecules, It is therefore suggested that the growth rate can be enhanced by depositing the film using higher RF power at higher pressure.
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Wang, Jen-Tsung, and 王仁宗. "Magnetron sputtering deposition of Ti-DLC films to enhance cutting tool performance." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/58840896911108902391.
Full textAbstract:
碩士龍華科技大學
機械工程系碩士班
102
In this study, thin diamond-like carbon (DLC) films were deposited onto tungsten carbide tools (P10) and glass substrates, by direct current (DC) reactive magnetron sputter at room temperature. We have used metallic Ti as the target and buffer layer, which provides better adhesion of the DLC films. The argon was the plasma gas and C4H10 was the reactive gas. The structure and surface properties of DLC coatings, prepared by various C4H10/(Ar+C4H10) flow ratios, were investigated by using X-ray diffraction spectroscopy, Raman spectroscopy. Dry turning of 7075 Al alloy tests was carried out with these coated tools.For Ti buffer coatings, the deposition parameters: 100 W DC power, 5 mtorr sputtering pressure, and 3 min deposition time were used. For Ti-DLC films (Ti-DLC/Ti buffer/P10), the DC power, sputtering pressure and deposition time were kept at 100 W, 6 mtorr and 20 min, respectively. By various C4H10/(Ar+C4H10) flow ratios ranging from 6~20%. The experimental results show that for dry turning of 7075 Al alloy with Ti-DLC/Ti buffer/P10 films coated, using C4H10/(Ar+C4H10) flow ratios 10% parameter, remarkably decreases roughness, roundness and flank wear. While the C4H10/(Ar+C4H10) flow ratios is increased from 12 to 20%, the value of ID/IG ratio decreases, and roughness, roundness and flank wear also deterioration.For another Ti-DLC films (Ti-DLC/Ti buffer/P10) deposition conditions, the C4H10/(Ar+C4H10) flow ratios, sputtering pressure and deposition time were fixed at 10%, 6 mtorr and 20 min, respectively. By various DC power ranging from 100~250 W. The experimental results show that for dry turning of 7075 Al alloy with Ti-DLC/Ti buffer/P10 films coated, using DC power 100 W, the lower roughness, roundness and flank wear were obtained.
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Carino, Emily V. "Underpotential deposition as a synthetic and characterization tool for core@shell dendrimer-encapsulated nanoparticles." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-3967.
Full textAbstract:
The synthesis and characterization of Pt core/ Cu shell (Pt@Cu) dendrimer-encapsulated nanoparticles (DENs) having full and partial Cu shells deposited via electrochemical underpotential deposition (UPD) is described. Pt DENs containing averages of 55, 147, and 225 Pt atoms immobilized on glassy carbon electrodes served as the substrate for the UPD of a Cu monolayer. This results in formation of Pt@Cu DENs. Evidence for this conclusion is based on results from the analysis of cyclic voltammograms (CVs) for the UPD and stripping of Cu on Pt DENs, and from experiments showing that the Pt core DENs catalyze the hydrogen evolution reaction before Cu UPD, but that after Cu UPD this reaction is inhibited. Results obtained by in-situ electrochemical X-ray absorption spectroscopy (XAS) confirm the core@shell structure. Calculations from density functional theory (DFT) show that the first portion of the Cu shell deposits onto the (100) facets, while Cu deposits lastly onto the (111) facets. The DFT-calculated energies for Cu deposition on the individual facets are in good agreement with the peaks observed in the CVs of the Cu UPD on the Pt DENs. Finally, structural analysis of Pt DENs having just partial Cu shells by in-situ XAS is consistent with the DFT-calculated model, confirming that the Cu partial shell selectively decorates the (100) facets. These results are of considerable significance because site-selective Cu deposition has not previously been shown on nanoparticles as small as DENs. In summary, the application of UPD as a synthetic route and characterization tool for core@shell DENs having well defined structures is established. A study of the degradation mechanism and degradation products of Pd DENs is provided as well. These DENs consisted of an average of 147 atoms per dendrimer. Elemental analysis and UV-vis spectroscopy indicate that there is substantial oxidation of the Pd DENs in air-saturated solutions, less oxidation in N₂-saturated solution, and no detectable oxidation when the DENs are in contact with H₂. Additionally, the stability improves when the DEN solutions are purified by dialysis to remove Pd²⁺-complexing ligands such as chloride. For the air- and N₂-saturated solutions, most of the oxidized Pd recomplexes to the interiors of the dendrimers, and a lesser percentage escapes into the surrounding solution. The propensity of Pd DENs to oxidize so easily is a likely consequence of their small size and high surface energy. Calculations from density functional theory (DFT) show that the first portion of the Cu shell deposits onto the (100) facets, while Cu deposits lastly onto the (111) facets. The DFT-calculated energies for Cu deposition on the individual facets are in good agreement with the peaks observed in the CVs of the Cu UPD on the Pt DENs. Finally, structural analysis of Pt DENs having just partial Cu shells by in-situ XAS is consistent with the DFT-calculated model, confirming that the Cu partial shell selectively decorates the (100) facets.
These results are of considerable significance because site-selective Cu deposition has not previously been shown on nanoparticles as small as DENs. In summary, the application of UPD as a synthetic route and characterization tool for core@shell DENs having well defined structures is established.
A study of the degradation mechanism and degradation products of Pd DENs is provided as well. These DENs consisted of an average of 147 atoms per dendrimer. Elemental analysis and UV-vis spectroscopy indicate that there is substantial oxidation of the Pd DENs in air-saturated solutions, less oxidation in N2-saturated solution, and no detectable oxidation when the DENs are in contact with H2. Additionally, the stability improves when the DEN solutions are purified by dialysis to remove Pd2+-complexing ligands such as chloride. For the air- and N2-saturated solutions, most of the oxidized Pd recomplexes to the interiors of the dendrimers, and a lesser percentage escapes into the surrounding solution. The propensity of Pd DENs to oxidize so easily is a likely consequence of their small size and high surface energy.text
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LI, Hao Sheng, and 黎昊昇. "Study on a High-Speed Deposition Technique for Electroplated Ni-Diamond Fine Wire Cutting Tool." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/25a24u.
Full textAbstract:
碩士健行科技大學
機械工程系碩士班
106
The diamond cutting wire is the main element using in the photoelectric semiconductor industry for the present advanced country, which is using in cutting machining for hard and brittle materials such as single crystalline or polycrystalline silicon, sapphire, silicon carbide, aluminum nitride, glass, ceramics, graphite etc.. As considering the environment protection, using the diamond wire cutting has been to be a new trend of the cutting processing. However, the finer the diamond wire, the more failure in the cutting process, also the more irregular the wire surface. The electroplating Ni-diamond composite fine wire was fabricated by using different conditions including electric current density, plating time, modified diamond powder (Ni-modified and Ti-modified), diamond powder adding concentration, and an additive, for observing and comparing the surface morphology and quality of the electroplating diamond wires. All the diameter of the diamond powder is 6~12 µm. The results indicated that without adding an additive, the Ni-modified diamond powder under the lower adding concentrations and low current density, well deposition quality could be obtained at very short time (20 sec) while the Ti-modified diamond with less deposition. When with an additive, both Ni-modified and Ti-modified diamond powder could be uniform and dense deposited on the fine wire (70 µm), especially the Ni-modified diamond powder gave uniform dispersion composite deposit without pile up deposit occurred.
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HUANG, WEN-RONG, and 黃文榮. "Multiple Thermal Reactive Diffusion/Deposition of Nb and V on SKD61 Tool Steel for Injection Screw." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/44605481455070797395.
Full textAbstract:
碩士國立高雄應用科技大學
模具系碩士在職專班
102
The multiple thermal reactive diffusion/deposition (TRD) process was used to deposit Nb and V on hot-worked tool steel SKD61 which is applied for injection screw. The samples were pre-treated by nitriding and boronizing and followed with TRD of Nb and V at different temperatures of 950℃, 1000℃, and 1050℃. The normal and cross-sectional hardness were measured by HV hardness tester. Indentation of HRC hardness was used to examine the adhesion property of the coatings. The polarization curve measurement identified the corrosion behavior of multiple TRD samples. Scanning electron microscopy (SEM) was used to observe the plan-view and cross sectional-view morphology of the coatings. The compositions of the coatings were analyzed by X-ray diffrctometer (XRD). The molten plastic rotation test was applied to examine the performance of SKD 61 as injection screw in the forced plastic fluid at a high temperature. The results indicate that all samples with TRD of Nb and V have better abrasion resistance and performance of molten plastic rotation testing compared with uncoated (and quenched and tempered) SKD 61. The sample was TRD-treated at 950℃ has a highest surface hardness of 3260 HV and a smallest thickness of 8μm among other samples. This induces the worst abrasion resistance and largest weight loss in molten plastic rotation testing. The polarization curves reveal that the corrosion currents for uncoated SKD 61 and SKD 61 with 950℃TRD of Nb and V are much higher than that with 1000℃and 1050℃TRD of Nb and V. The worse corrosion resistance of the uncoated SKD 61 and SKD 61 with 950℃TRD increases the tendency of weight loss in the forced plastic fluid at high temperature in the molten plastic rotation testing. In addition, the coatings of TRD of Nb and V comprised V8C7, NbN, αFe(V), and Nb6C5 by XRD analysis.
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Tsai, Chun-Te, and 蔡俊德. "The Development of a Software simulator with Trainer of Chemical Vapor Deposition Equipment for Cluster Tool Manufacturing." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/35100379881399037303.
Full textAbstract:
碩士國立交通大學
工學院碩士在職專班精密與自動化工程學程
93
This thesis is to design a simulator incorporated with trainer of a chemical vapor deposition system for 300mm cluster tool in semiconductor manufacture. The integration of simulator and trainer has many advantages that the commercial trainers can not provide. In addition to providing the functions available in the market, i.e. Human-computer Interface and normal operation, the developed trainer accepts any receipt by the operator then shows what the process is going on in terms of animation and process data display. It also provides fault modes to be adjusted on screen so that the operators can learn how to handle recovery modes. The user can thus change all set-ups on the user interface to learn the impact of each value on the production and become more familiar with the relationship between the whole processing and equipments.
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Chuag, Kai-Chuan, and 莊凱權. "Optimization for Thermal Reactive Diffusion/Deposition of Nb、V and Cr on Cold –Work SKD11 Tool Steel." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/xssun3.
Full textAbstract:
碩士國立高雄應用科技大學
模具工程系碩士班
103
Taguchi method was applied to analyze the optimum process parameters for thermal reactive diffusion/deposition (TRD) of Cr and Nb and V metallic elements on cold-worked tool steel of SKD11. The process parameters such as diffusion element, diffusion time and diffusion temperature were chosen as the controlling factors. The surface Vickens Hardness, coatings tickness, aluminium cold-forging weight loss and low carbon steel cold-forging weight loss were examined using an L9 orthogonal array. The analysis of variance (ANOVA) combined with confirmation experiment were employed to obtain the optimum parameters. In addition, other characteristics such as abrasion resistance testing, adhesion testing and microstructure examination were used to investigate some fundamental properties and microstructure. The results indicate that the optimal process for coating’s thickness is A1 B3 C3 with 20.05 um thickness, the optimal process for surfuce Vickens Hardness is A3 B3 C1 with 3870.5 HV, the optimal process for the aluminium cold-forging weight loss is A3 B3 C2 with weight loss of 0.000984365 g/〖cm〗^2 and the optimal process for the low carbon steel cold-forging weight loss is A3 B3 C3 with weight loss of 0.001653975 g/〖cm〗^2. The abrasion resistance of test pieces treated with TRD of Cr, Nb and V is obviously higher than quenching and tempering test pieces and the phases of the coatings show some chrome carbide, chrome nitride and niobium carbide.
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Bleakie, Alexander Q. "Dynamic feature analysis of an industrial PECVD tool with connection to operation-dependent degradation modeling." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1617.
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An analysis that is based on the monitoring of dynamic features from in-situ sensors of an industrial PECVD tool is presented. Linear Discriminant Analysis is used to determine which features are the most sensitive to various changes in the tool condition. The concept of Confidence Values (CVs) is used to quantify statistical changes of these dynamic features as the condition of the tool changed. Two data sets were collected from a PECVD tool in the facilities of a well-known equipment supplier. Dynamic features coming from the RF plasma power and matching capacitors’ sensors are shown to be sensitive to various changes in the cleaning cycles for Si-N, Si-O₂, and TEOS depositions. Quantifying the statistical distributions of the sensitive sensor features during tool condition changes is important for determining which sensor features are necessary to monitor in order to predict the tool chamber health. Results show that these RF plasma sensors could be used to track changes inside the tool chamber.text
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Chang, Yu-Fu, and 張祐福. "Fabrication of Ni – Co Alloy Co-deposition of Micro Diamond Tool and Its Applications to Synchronous Electrical Discharge Grinding." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/qsy5rt.
Full textAbstract:
碩士國立高雄應用科技大學
模具工程系碩士班
102
This research attempts to achieve a synchronized hybrid process of micro-EDM grinding (micro-EDMG, or μEDMG) on a single machine, it is aimed at saving the secondary precision grinding process after general micro-EDM process in micro-machining fields. First, the micro-tool of tungsten carbide was dressed to 0.3 mm diameter by a WEDG (wire electrical discharge grinding) system, and co-deposited in the nickel electro-plating bath with 6~12 μm of diamond abrasives. A low speed spindle is used for electro-plating, and then, another high speed spindle up to 20 KRPM is adopted to perform synchronous process of micro-EDM grinding. In our previous studies, it had been confirmed the feasibility of the synchronized micro-EDM and micro grinding process with 10 μm of lateral depth into work piece by precision positioning. However, there were severe problems of residual craters and debris accumulation, causing by the secondary discharge between both electrodes. This study proposes two methods to overcome the defects and increase machining quality compared to the previous researches. One of them is to dress standard cylindrical micro-tool into the helical groove with a short taper, making the spiral grooves serve as the chips pocket to increase debris expelling efficiency. By appending cobalt ion into the plating bath to achieve Ni-Co alloy co-deposition, it is found that both more uniform dispersion of abrasives on the tool’s surface and richer diamond grains and stronger mechanical property in wearing resistance are achieved. By doing so, significant improvement of the precision quality and machining efficiency for such a hybrid process, and the anti-worn out capability of the micro-tool are verified through the conducted surface of micro-holes. Moreover, only one step of processing is required on the same machine and both higher efficiency and better quality by applying micro diamond tools to fabrication of under 0.33 mm micro-holes co-axially and precision circle with 0.3 mm thick of SUS-304 is achieved. Fabrication conditions of micro diamond tools by Ni-Co co-deposition is conducted under Ni-Co/Diamond bath with 5 g/l of abrasives concentration, 2 RPM of rotation, 7 ASD of current density, and electro-plating interval of 5 min. It was verified from EDS analysis that the diamond amount occupied 31.77 wt(%) and cobalt element occupied 11.31 wt(%). Such a micro-tool with processes parameters of 20 KRPM, 30 μm/min and feeding depth of 2 mm depth achieved the best surface roughness of Ra 0.107 μm. Its diameter difference between entrance and exit also appeared to be the value of 9 μm. From oscilloscope observed EDM waveform and the 10 μm scaled SEM picture of tool’s profile, it is confirmed that synchronous micro-EDMG occurred during the operation processes. Furthermore, it is found from the machined surface that there are three phases of EDMG processes contributed to this novel strategy. Namely, the first phase during machining depth of 0~1.0 mm along z-direction, it is dominated by micro-EDM drilling with roughing current of 0.5A. There is almost no grinding, or the grinding chips are totally re-discharged again by the second discharge process. The second phase during 1.0~1.5 mm is contributed to rough EDM grinding of the micro holes, some recast layers are pulling-pushed or scratched, and some craters are refilled to some sort of level. There seems some kind of hybrid machining effects around EDM spark’s spot. Finally, the third phase during 1.5~2.0 mm, there are some sort of complete grinding to remove the recast layers and craters to a fine surface in this finishing stage. Besides, from SEM photo of 1 μm scale, it is found that not only simply EDM or simply mechanical grinding, but also plastic machining regions observed. They are contributed from micro-scale removing mechanism during micro-EDMG processes, in which recast layers are pulling-pushed and scratched to longer chips, and some craters are refilled again. On the other way, due to such a short period of EDM pulse on-time, the shoveled chip by grinding abrasive is the most possible position to be re-discharged again to shape a non-typical EDM crater. Keywords: micro-EDM (electrical discharge machining), micro-EDMG (micro-EDM grinding), synchronous processes, hybrid Ni-Co co-deposition, Diamond Tool
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Shadrach, Kelita. "Investigating the Fauresmith stone tool industry from Pit 4 West at Canteen Kopje, Northern Cape Province, South Africa." Thesis, 2018. https://hdl.handle.net/10539/26891.
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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science, Faculty of Science University of the Witwatersrand, Johannesburg 2018Canteen Kopje has yielded rare in-situ assemblages of the Fauresmith, a poorly defined industry often associated with the later Acheulean. The Fauresmith contains precocious developments in technology as early as ~0.5 Ma–features which only become widespread in the ensuing Middle Stone Age. The Fauresmith as a regional industry provides insight into technological practices during the period of significant behavioural diversification associated with archaic Homo sapiens. Previous excavations were conducted with relatively low spatial resolution. A new excavation, Pit 4 West, was conducted to investigate the spatial, stratigraphic and contextual association of the Fauresmith horizon in more detail. A multi-disciplinary fineresolution geoarchaeological approach was applied. A nuanced assessment of the Fauresmith’s context was developed, with macroscopic and microscopic analyses allowing for the identification of site formation processes influencing assemblages. The artefact sample size for the site was increased and the presence of diagnostic tools has aided in formally defining the Fauresmith at Canteen Kopje.
XL2019
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Lee, Chun-I., and 李俊毅. "Study on the DC-Pulsed Plasma Chemical Vapor Deposition Coating DLC Films of the Oxynitriding-treated AISI H13 Tool Steel." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/8mujr2.
Full textAbstract:
碩士國立臺北科技大學
材料及資源工程系研究所
100
A surface treatment is usually used to improve tool life. DLC has many superior properties, such as high mechanical hardness, high wear resistance, a low friction coefficient and chemical inertness. The oxynitriding process uses air or steam at the end of the nitriding stage as an oxidizing medium, which is an integral part of the treatment. During the oxidation process, most steels can form several kinds of oxides (Fe2O3 and Fe3O4). Generally, the Fe3O4 layer of the oxidation treatment can effectively protect and improve the erosion and corrosion resistance of steels. Therefore, the oxynitriding/DLC duplex treatment was utilized for treating AISI H13 tool steel in an attempt to increase tool life. In this study, the diamond-like carbon films were prepared by DC-pulsed plasma CVD after the oxynitride treatment of AISI H13 tool steel. In order to investigate the DLC films properties, Raman spectroscopy analysis, wear test, adhesion and hardness tests were performed. The study of the parameters of DC-pulsed plasma CVD process included the pulsed voltage, pre-treatment of argon gas and the substrate temperature. The experimental results showed that a 0.05-0.06 mm oxynitride layer and 1-2 μm of DLC thin film could be obtained after the oxynitride/DLC duplex treatment. The duplex coating layers had the optimal properties when treated by a low pulse voltage (-1.5 kV), pre-treatment of argon gas for 15 min and the substrate kept at a 50°C condition. Meanwhile, the oxynitride/DLC duplex treatments possessed the highest surface hardness (Hv0.01 1457), lowest wear volume (2.25 × 10-3 mm3) and lower friction coefficient (0.06).
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張國彥. "Effects of chamber wall polymer deposition and parts consumption on plasma RF parameters in a MERIE tool for silicon oxide etching." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/85446628438462902872.
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Marques, Tiago Matias. "Development of a strategy for defining the orientation of a deposition tool in 3D print jobs - algorithms taking into account metal printing." Master's thesis, 2020. http://hdl.handle.net/10316/93923.
Full textAbstract:
Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e TecnologiaGraças aos desenvolvimentos tecnológicos, as Revoluções Industriais levaram a um aumento do nível de automação nas empresas através da implementação de novos métodos de produção e da introdução de células robotizadas nas linhas de produção. No entanto, alguns sectores, nomeadamente o sector da construção metálica, ainda se baseiam em processos convencionais que requerem a utilização de uma grande quantidade de mão-de-obra humana.Esta tese apresenta a contribuição para o desenvolvimento de uma célula robotizada de impressão 3D, concebida para automatizar a produção de peças metálicas para o sector da construção, através do desenvolvimento de uma estratégia para definir a orientação de uma ferramenta de deposição acoplada ao fim de um robô.Para esse objetivo, foi desenvolvido um programa C#, com a capacidade de analisar a geometria de uma peça processada por um software de corte e cria um ficheiro compatível com a célula robótica com a atribuição da orientação da ferramenta de impressão paralela à respetiva superfície, o que conduz a um processo de impressão melhorado. Estas melhorias podem ser um tempo de impressão mais rápido, menos desperdício de material, e melhor acabamento superficial das peças impressas.Para verificar o funcionamento do algoritmo, foi necessário realizar simulações num ambiente virtual presente no RobotStudio que consiste nos mesmos componentes do sistema físico, nomeadamente um braço robótico ABB IRB 4600, uma pista linear IRBT 2006, e uma ferramenta de impressão TPS 400i CMT Advanced Fronius.Embora os objetivos definidos durante o desenvolvimento tenham sido alcançados pelo ajuste correto da orientação da ferramenta de impressão de acordo com a superfície da peça, não foi possível automatizar totalmente a estratégia implementada, o que deixa espaço para futuras melhorias.
Thanks to technological developments, the Industrial Revolutions have led to an increase in the level of automation in companies through the implementation of new production methods and the introduction of robotized cells in production lines. However, some sectors, namely the metal construction sector, are still based on conventional processes that require the use of a high amount of human labor.This thesis presents the contribution to the development of a 3D printing robotic cell, designed to automate the production of metallic parts for the construction sector, through the development of a strategy to define the orientation of a deposition tool coupled to the end of a robot.In order to achieve this, a C# program was developed, with the capacity to analyze the geometry of a piece, that has been processed by a slicing software, and creates a file compatible with the robotic cell with the assignment of the printing tool's orientation parallel to the respective surface which leads to improvements in the printing process. These improvements can be faster printing time, less wasted material, and better superficial finish of the parts printed.To verify the algorithm functioning, simulations had to be performed in a virtual environment present in RobotStudio consisting of the same components on the physical system, namely an ABB IRB 4600 robotic arm, a linear IRBT 2006 track, and a TPS 400i CMT Advanced Fronius print tool.Although the objectives defined during the development have been achieved by the right adjustment of the printing tool orientation according to the surface of the part, it was not possible to fully automate the strategy implemented, which leaves room for future improvements.
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Ascenso, Francisco José Ribeiro. "Development of a strategy to define the orientation of a deposition tool in 3D printing tasks - simulation in Matlab and realization in RobotStudio." Master's thesis, 2020. http://hdl.handle.net/10316/94019.
Full textAbstract:
Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e TecnologiaEsta tese integra um projecto desenvolvido na Universidade de Coimbra pelo grupo AMC (Additive Manufacturing Constructions) que pretende automatizar uma célula robótica para a Produção de Aditiva de Metais. Este trabalho apresenta uma solução possível para melhorar o conceito de impressão metálica 3D, quando aplicada a um robô industrial. A impressão de peças de grandes dimensões e geometrias complexas continua a ser um desafio para a indústria de produção aditiva. Este tipo de peças requer normalmente um elevado tempo de produção e desperdício de material. Assim, foi criado um método que torna o processo de impressão mais eficiente, reduzindo o tempo total de impressão e o desperdício de material, através de um procedimento que altera a orientação de impressão com base na geometria da peça a ser fabricada.Foi construído um programa que analisa G-code, na linguagem de programação C#, para recolher informação sobre a geometria da peça e calcular a melhor orientação de impressão para cada caso. Para garantir que o algoritmo funciona correctamente, foi criada uma estação robótica no RobotStudio, que simula o comportamento de um robô real, permitindo verificar o funcionamento do algoritmo e identificar possíveis melhorias, bem como, um programa em Matlab que permitiu verificar e representar graficamente a maior parte das operações realizadas.Todo o procedimento considera a utilização da tecnologia de impressão WAAM, um braço robotico ABB IRB 4600, um eixo linear IRBT 2005, e a ferramenta de impressão TPS 400i CMT Advanced Fronius.Embora todos os objectivos tenham sido alcançados, a metodologia não é totalmente automatizada, deixando espaço para várias melhorias futuras.
This thesis integrates a project developed at the University of Coimbra by the Additive Manufacturing Constructions (AMC) group that intends to automate a robotic cell for Metallic Additive Manufacturing. This work presents a possible solution to improve the concept of 3D metallic printing when applied to an industrial robot. Printing large parts and complex geometries remains a challenge for the additive manufacturing industry. This type of part usually requires a high production time and waste of material. Thus a method has been created that makes the printing process more efficient, reducing total printing time and wasted material, through a procedure that changes the printing orientation based on the geometry of the part to be manufactured.A G-code analyzer was built in C# programming language to collect information about the geometry of the part and calculate the best printing orientation for each case. To guarantee that the algorithm works properly, a robotic station was created in RobotStudio, which simulates the behavior of a real robot, allowing to verify the algorithm's functioning and identify possible improvements, as well as, a program in Matlab that allowed to verify and graphically represent most of the operations performed.The whole procedure considers the use of WAAM printing technology, an ABB IRB 4600 robotic arm, an IRBT 2005 linear track, and the TPS 400i CMT Advanced Fronius printing tool.Although all the objectives have been achieved, the methodology is not fully automated, leaving space for several future improvements.
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Fu, Qilin. "High dynamic stiffness nano-structured composites for vibration control : A Study of applications in joint interfaces and machining systems." Doctoral thesis, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176869.
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Vibration control requires high dynamic stiffness in mechanical structures for a reliable performance under extreme conditions. Dynamic stiffness composes the parameters of stiffness (K) and damping (η) that are usually in a trade-off relationship. This thesis study aims to break the trade-off relationship. After identifying the underlying mechanism of damping in composite materials and joint interfaces, this thesis studies the deposition technique and physical characteristics of nano-structured HDS (high dynamic stiffness) composite thick-layer coatings. The HDS composite were created by enlarging the internal grain boundary surface area through reduced grain size in nano scale (≤ 40 nm). The deposition process utilizes a PECVD (Plasma Enhanced Chemical Vapour Deposition) method combined with the HiPIMS (High Power Impulse Magnetron Sputtering) technology. The HDS composite exhibited significantly higher surface hardness and higher elastic modulus compared to Poly(methyl methacrylate) (PMMA), yet similar damping property. The HDS composites successfully realized vibration control of cutting tools while applied in their clamping interfaces. Compression preload at essential joint interfaces was found to play a major role in stability of cutting processes and a method was provided for characterizing joint interface properties directly on assembled structures. The detailed analysis of a build-up structure showed that the vibrational mode energy is shifted by varying the joint interface’s compression preload. In a build-up structure, the location shift of vibration mode’s strain energy affects the dynamic responses together with the stiffness and damping properties of joint interfaces. The thesis demonstrates that it is possible to achieve high stiffness and high damping simultaneously in materials and structures. Analysis of the vibrational strain energy distribution was found essential for the success of vibration control.
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TANG, YA-MEI, and 湯雅玫. "Depositing Chromium Nitride Film on SK2 Tool Steel at Low Temperature by Utilizing High Power Impulse Magnetron Sputtering." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/bn35ud.
Full textAbstract:
碩士國立虎尾科技大學
機械與電腦輔助工程系碩士班在職專班
107
High power impulse magnetron sputtering (HiPIMS) is a novel coating technology. HiPIMS has high impulse voltage range that induces higher current for greater power to increase atomic ionization rate of target material and sputtered ion energy. The deposited thin film has dense and uniform microstructure along with high adherence, superb deposition quality of coating can be obtained as deposited at lower deposition temperature. Chromium nitride (CrN) film has high hardness, wear resistance, oxidation resistance and corrosion resistance, which been widely used in the surface treatment of various tools and molds. In this study, pure chromium was used as the target material, a thin chromium (Cr) interlayer deposited using argon gas, followed by mixture of argon and nitrogen gaseous deposition of chromium nitride (CrN) film onto SK2 tool steel and silicon wafer. The mechanical properties of CrN film deposited at different substrate temperatures and using different process parameters were compared in this study. The results show that, as the ratio of nitrogen to argon is increased, the corresponding peak pulse current of the target is higher, indicating that more nitrogen participates in the reaction and the plasma density is increased. However, the formation of nitride on the target surface causes target poisoning, so that the deposition rate does not increase with the pulse peak current, but overall, compared with DC sputtering, the HiPIMS deposition process does not present obvious hysteresis effects and consequent deposition rate drops. The nitrogen content of the film deposited on the silicon wafer increases proportionally with the nitrogen: to argon flow ratio, and finally approaches a fixed value, and reflects the same coating hardness tendency. The coated SK2 tool steel did not reflect the same hardness change trend because of the large difference in hardness of the substrate. At the same time, if the deposition temperature is too high above 300 °C, the SK2 tool steel will soften, so that the hardness difference between the substrate and the film becomes larger, resulting in a decrease in the overall hardness. Utilizing HiPIMS technology with high ionization rate, a chromium nitride coating with high adhesion and high hardness can be obtained without the need for additional substrate heating. It can be applied to a variety of substrates with low heat resistance and expand the range of applications of chromium nitride.