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Dissertations / Theses on the topic 'Ceramics cutting'

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Published: 4 June 2021
Last updated: 26 January 2023

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1

PIRES, PATRICIO JOSE MOREIRA. "THE USE OF DRILLING CUTTING FOR RED CERAMICS PRODUCTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=14991@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
AGÊNCIA NACIONAL DE PETRÓLEO
O presente trabalho sugere uma alternativa inovadora para o tratamento e disposição do cascalho de perfuração, um dos mais complexos resíduos da indústria de petróleo contendo, em geral, altas taxas de sais solúveis e hidrocarbonetos. Estas características o tornam um resíduo nocivo ao meio ambiente. Neste trabalho é avaliada a incorporação de cascalho de perfuração na massa argilosa para produção de cerâmica vermelha. O método consiste no processamento industrial, realizado a elevadas temperaturas, a fim de se obter um material sólido, resistente e inerte. A incorporação de cascalho de perfuração na produção de cerâmica vermelha apresentou-se como uma alternativa economicamente viável e tecnicamente segura para o tratamento e destinação final deste resíduo. Uma vez que o processo de queima, inerente a produção de peças cerâmicas, encapsula e reduz a baixos teores os constituintes perigosos do cascalho de perfuração. Os resultados obtidos neste trabalho serviram de subsídios para a concessão de licença ambiental para utilização da técnica desenvolvida na remediação de cascalho de perfuração no Estado da Bahia.
This thesis presents an innovative treatment technique for drilling cuttings, one of the most complex wastes of the oil industry. This waste is considered hazardous due to its high salt and hydrocarbons content and poses serious threats to the environment. The treatment process involves the incorporation of drilling cuttings to the clayey soil mass used for making bricks. It consists on applying high temperatures, over 8000C, to the clayey soil mass in order to obtain a solid, resistant and inert material. The results of the experimental programme have shown that this innovative process is technical safe and economical viable. As a result, Petrobras obtained an environmental license in the city of Mata de São João , State of Bahia, to produce in a large scale red bricks using drilling cuttings incorporated to the clayey soil mass.
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2

Gudimetla, Prasad. "Abrasive waterjet cutting of polycrystalline alumina ceramics-modelling, process optimisation & finite element analysis." Thesis, Queensland University of Technology, 2001.

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3

Yan, Yinzhou. "High-quality laser machining of alumina ceramics." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/highquality-laser-machining-of-alumina-ceramics(3dd60fb6-5bda-4cc9-8f00-f49b170ca6aa).html.

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Alumina is one of the most commonly used engineering ceramics for a variety of applications ranging from microelectronics to prosthetics due to its desirable properties. Unfortunately, conventional machining techniques generally lead to fracture, tool failure, low surface integrity, high energy consumption, low material removal rate, and high tool wear during machining due to high hardness and brittleness of the ceramic material. Laser machining offers an alternative for rapid processing of brittle and hard engineering ceramics. However, the material properties, especially the high thermal expansion coefficient and low thermal conductivity, may cause ceramic fracture due to thermal damage. Striation formation is another defect in laser cutting. These drawbacks limit advanced ceramics in engineering applications. In this work, various lasers and machining techniques are investigated to explore the feasibility of high-quality laser machining different thicknesses of alumina. The main contributions include: (i) Fibre laser crack-free cutting of thick-section alumina (up to 6-mm-thickness). A three-dimensional numerical model considering the material removal was developed to study the effects of process parameters on temperature, thermal-stress distribution, fracture initiation and propagation in laser cutting. A rapid parameters optimisation procedure for crack-free cutting of thick-section ceramics was proposed. (ii) Low power CW CO2 laser underwater machining of closed cavities (up to 2-mm depth) in alumina was demonstrated with high-quality in terms of surface finish and integrity. A three-dimensional thermal-stress model and a two-dimensional fluid smooth particle hydrodynamic model (SPH) were developed to investigate the physical processes during CO2 laser underwater machining. SPH modelling has been applied for the first time to studying laser processing of ceramics. (iii) Striation-free cutting of alumina sheets (1-mm thickness) is realised using a nano-second pulsed DPSS Nd: YAG laser, which demonstrates the capability of high average power short pulsed lasers in high-quality macro-machining. A mechanism of pulsed laser striation-free cutting was also proposed. The present work opens up new opportunities for applying lasers for high-quality machining of engineering ceramics.
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4

Guo, Zihong. "Experimental and numerical analysis of abrasive waterjet drilling of brittle materials /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/7092.

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5

Heča, Jan. "Řezná keramika a její efektivní využití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230358.

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Thesis dealing with cutting ceramics and its efficient use. Introduction describes the general characteristics of the cutting of ceramics, its history and development and production of various kinds. This section describes the mechanical and physical properties with potential application in machining. The se-cond part is an overview of cutting-frame in the range of selected world leaders. Ano-ther section focuses on general assessment of the power of cutting tools and other ma-terials comparison. The fourth part, is comparing the working conditions of producers and tools intended for cutting.
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6

Fujita, Humberto [UNESP]. "Retificação da alumina com rebolo diamantado usando diferentes métodos de lubri-refrigeração." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/88465.

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Made available in DSpace on 2014-06-11T19:23:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-05-04Bitstream added on 2014-06-13T18:50:40Z : No. of bitstreams: 1 fujita_h_me_bauru.pdf: 3757663 bytes, checksum: 66acc24c6f3d11d42e726d1b452899b3 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O sucesso da cerâmica estrutural na maioria das aplicações depende não somente das propriedades do material e do projeto da peça, mas também da qualidade do produto usinado. Um dos fatores citados como obstáculo à ampla utilização das cerâmicas é a falta de confiabilidade dos componentes de cerâmica, em função da grande dispersão dos valores de resistência mecânica provocada por defeitos que podem ter origem no processo de retificação. A retificação de cerâmica, assim como na indústria de processamento metal-mecânica, é realizada normalmente com abundância de fluidos de corte. A utilização destes fluidos refrigerantes resulta em problemas ecológicos, fisiológicos e econômicos. Desde a última década, a opinião pública, o mercado, as leis e regulamentos têm pressionado as indústrias para considerar os riscos ambientais na manufatura. Com o propósito de avaliar alternativas ao método convencional de lubri-refrigeração, foi estudada a viabilidade da técnica de refrigeração otimizada, onde o fluido de corte é aplicado à mesma velocidade periférica do rebolo, penetrando na região de corte com menos turbulência. Também foi analisada a técnica da Mínima Quantidade de Lubrificação (MQL), na qual o grande volume de fluido de corte é substituído por um jato de ar contendo uma quantidade ínfima de lubrificante. Os métodos foram comparados através da análise de desempenho durante o processo de retificação (forças de corte, emissão acústica, energia de retificação) e pela caracterização dos corpos de prova (rugosidade, danos subsuperficiais) e do rebolo (relação G). A profundidade de corte e o efeito do spark-out também formaram parte do escopo deste trabalho. Os resultados obtidos mostraram que a profundidade de corte exerce grande influência durante o processo...
The success of structural ceramics in most applications depends not only on the materials properties and component design, but also the quality of machined products. One factor usually mentioned as a barrier to the wide use of ceramics is the lack of reliability of ceramic components, because the variability on the mechanical strength caused by defects that can be impaired in the grinding process. The grinding of ceramics, as much as with steel grinding is performed generally with excess of cutting fluids (coolants). The use of coolants results in serious ecological, physiological and economic issues. Since last decade the public opinion, the market, the laws and regulations have pushed the industries to consider the environmental risks in the manufacturing process. Then, in order to evaluate alternatives to the conventional method of cooling and lubrication, it was studied the viability of the optimized technique, where the cutting fluid is applied to the same peripherical speed of the wheel, penetrating in the cutting zone with less turbulence. Also, it was verified the technique of Minimum Quantity of Fluid (MQF), where a large amount of cutting fluid is replaced by an air compressed flow containing a small quantity of lubricant. The methods were compared through performance analysis during the grinding process (cutting forces, acoustic emission and specific grinding energy) and by characterization of specimens (roughness, subsurface damage) and wheel (G ratio). The depth of cut and the effect of spark-out were part of the scope of this work too. The results obtained showed that the depth of cut has great influence during the process and in the characterization of ceramics, while spark-out does not seem to be so significant. Another conclusion is that MQF is not viable in ceramics grinding with the working conditions proposed. The results obtained... (Complete abstract, click electronic access below)
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7

Fujita, Humberto. "Retificação da alumina com rebolo diamantado usando diferentes métodos de lubri-refrigeração /." Bauru : [s.l.], 2007. http://hdl.handle.net/11449/88465.

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Orientador: Eduardo Carlos Bianchi
Banca: Jaime Gilberto Duduch
Banca: Luiz Eduardo de Angelo Sanchez
O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp
Resumo: O sucesso da cerâmica estrutural na maioria das aplicações depende não somente das propriedades do material e do projeto da peça, mas também da qualidade do produto usinado. Um dos fatores citados como obstáculo à ampla utilização das cerâmicas é a falta de confiabilidade dos componentes de cerâmica, em função da grande dispersão dos valores de resistência mecânica provocada por defeitos que podem ter origem no processo de retificação. A retificação de cerâmica, assim como na indústria de processamento metal-mecânica, é realizada normalmente com abundância de fluidos de corte. A utilização destes fluidos refrigerantes resulta em problemas ecológicos, fisiológicos e econômicos. Desde a última década, a opinião pública, o mercado, as leis e regulamentos têm pressionado as indústrias para considerar os riscos ambientais na manufatura. Com o propósito de avaliar alternativas ao método convencional de lubri-refrigeração, foi estudada a viabilidade da técnica de refrigeração otimizada, onde o fluido de corte é aplicado à mesma velocidade periférica do rebolo, penetrando na região de corte com menos turbulência. Também foi analisada a técnica da Mínima Quantidade de Lubrificação (MQL), na qual o grande volume de fluido de corte é substituído por um jato de ar contendo uma quantidade ínfima de lubrificante. Os métodos foram comparados através da análise de desempenho durante o processo de retificação (forças de corte, emissão acústica, energia de retificação) e pela caracterização dos corpos de prova (rugosidade, danos subsuperficiais) e do rebolo (relação G). A profundidade de corte e o efeito do "spark-out" também formaram parte do escopo deste trabalho. Os resultados obtidos mostraram que a profundidade de corte exerce grande influência durante o processo... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The success of structural ceramics in most applications depends not only on the materials properties and component design, but also the quality of machined products. One factor usually mentioned as a barrier to the wide use of ceramics is the lack of reliability of ceramic components, because the variability on the mechanical strength caused by defects that can be impaired in the grinding process. The grinding of ceramics, as much as with steel grinding is performed generally with excess of cutting fluids (coolants). The use of coolants results in serious ecological, physiological and economic issues. Since last decade the public opinion, the market, the laws and regulations have pushed the industries to consider the environmental risks in the manufacturing process. Then, in order to evaluate alternatives to the conventional method of cooling and lubrication, it was studied the viability of the optimized technique, where the cutting fluid is applied to the same peripherical speed of the wheel, penetrating in the cutting zone with less turbulence. Also, it was verified the technique of Minimum Quantity of Fluid (MQF), where a large amount of cutting fluid is replaced by an air compressed flow containing a small quantity of lubricant. The methods were compared through performance analysis during the grinding process (cutting forces, acoustic emission and specific grinding energy) and by characterization of specimens (roughness, subsurface damage) and wheel (G ratio). The depth of cut and the effect of "spark-out" were part of the scope of this work too. The results obtained showed that the depth of cut has great influence during the process and in the characterization of ceramics, while "spark-out" does not seem to be so significant. Another conclusion is that MQF is not viable in ceramics grinding with the working conditions proposed. The results obtained... (Complete abstract, click electronic access below)
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8

Fialová, Kateřina. "Řezná keramika a její efektivní využití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228321.

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The diploma work is focused on the ceramic tool materials and its effective use. The introductory part of the work contains the detail characteristic of the ceramic tool materials from the point of view of their dividing, physic-mechanical propertis, production methods and marking. The main part of the work is focused to judging of the ceramic portion at the production assortment of the top World producers of tool materials and to evaluation of cutting ability of the particular materials of these producers. The detail analysis of recommended cutting conditions, which is aimed to an effective use of the ceramic materials, had been worked up for this purpose. The technical economic analysis confirms, that the present effective aplications of ceramic are limited only for specific cases of machining cast irons, steels and alloys.
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9

Podešva, Lukáš. "Řezná keramika a její efektivní využití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229214.

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In the first part of this diploma thesis there are discribed basic findings about cutting ceramics (sorts, notation, structure, physical-mechanical properties, using, production) and it evaluates this tool material from the aspect of cutting power. The second part focuses on complex data processing about assortment of ceramics cutting materials of significant tool materials producers and comparison of service conditions (kind of mechanided materials, cutting conditions), which are recommend for effective turning by producers.
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10

Zhong, Yu Mechanical &amp Manufacturing Engineering Faculty of Engineering UNSW. "A study of the cutting performance in multipass abrasive waterjet machining of alumina ceramics with controlled nozzle oscillation." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/41216.

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An experimental investigation has been undertaken to study the depth of cut in multipass abrasive waterjet (AWJ) cutting of an 87% alumina ceramic with controlled nozzle oscillation. The experimental data have been statistically analysed to study the trends of the depth of cut with respect to the process parameters. It has been found that multipass cutting with controlled nozzle oscillation can significantly increase the depth of cut. Within the same cutting time and using the same cutting parameters other than the jet traverse speed, it has been found that multipass cutting with nozzle oscillation can increase the depth of cut by an average of 74.6% as compared to single pass cutting without nozzle oscillation. Furthermore, a multipass cutting with higher nozzle traverse speeds can achieve a larger depth of cut than a single pass cutting at a low traverse speed within the same cutting time. A recommendation has been made for the selection of appropriate process parameters for multipass cutting with nozzle oscillation. In order to estimate the depth of cut on a mathematical basis, predictive models for the depth of cut in multipass cutting with and without nozzle oscillation have been developed using a dimensional analysis technique. The model development starts with the models for single pass cutting which are then extended to multipass cutting where considerations are given to the change of the actual standoff distance after each pass and the variation of kerf width. These predictive models has been numerically studied for their plausibility by assessing their predicted trends with respect to the various process variables, and verified qualitatively and quantitatively based on the experimental data. The model assessment reveals that the developed models correlate very well with the experimental results and can give adequate predictions of this cutting performance measure in process planning.
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11

Liu, Hua. "A study of the cutting performance in abrasive waterjet contouring of alumina ceramics and associated jet dynamic characteristics." Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/16110/1/Hua_Liu_Thesis.pdf.

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Abrasive waterjet (AWJ) cutting is one of the most recently developed nontraditional manufacturing technologies. It has been increasingly used in industry owing to its various distinct advantages over the other cutting technologies. However, many aspects of this technology require to be fully understood in order to increase its capability and cutting performance as well as to optimize the cutting process. This thesis contains an extensive literature review on the investigations of the various aspects in AWJ machining. It shows that while considerable work has been carried out, very little reported research has been found on the AWJ contouring process although it is a common AWJ cutting application. Because of the very nature of the AWJ cutting process, the changing nozzle traverse direction involved in AWJ contouring results in kerf geometrical or shape errors. A thorough understanding of the AWJ contouring process is essential for the reduction or elimination of these shape errors. It also shows that a lack of understanding of the AWJ hydrodynamic characteristics has limited the development of cutting performance models that are required for process control and optimization. Accordingly, a detailed experimental investigation is presented in this thesis to study the various cutting performance measures in AWJ contouring of an 87% alumina ceramic over a wide range of process parameters. For a comparison purpose, the study also considers AWJ straight-slit cutting. The effects of process parameters on the major cutting performance measures in AWJ contouring have been comprehensively discussed and plausible trends are amply analysed. It finds that the taper angles on the two kerf walls are in different magnitudes in AWJ contouring. The kerf taper on the outer kerf wall increases with the arc radius (or profile curvature), while that on the inner kerf wall decreases. Moreover, the depth of cut increases with an increase in arc radius and approaches the maximum in straight cutting for a given combination of parameters. The other process variables affect the AWJ contouring process in a way similar to that in straight cutting. The analysis has provided a guideline for the selection of process parameters in the AWJ contouring of alumina ceramics. In order to predict the cutting performance in process planning and ultimately optimize the cutting process, mathematical models for the major cutting performance measures in both straight-slit cutting and contouring are developed using a dimensional analysis technique. The models are then verified by assessing both qualitatively and quantitatively the model predictions with respect to the corresponding experimental data. It shows that the models can adequately predict the cutting performance measures and form the essential basis for developing strategies for selecting the optimum process parameters in AWJ cutting. To achieve an in-depth understanding of the jet dynamic characteristics such as the velocity and pressure distributions inside a jet, a Computational Fluid Dynamics (CFD) simulation is carried out using a Fluent6 flow solver and the simulation results are validated by an experimental investigation. The water and particle velocities in the jet are obtained under different input and boundary conditions to provide an insight into the jet characteristics and a good understanding of the kerf formation process in AWJ cutting. Various plausible trends and characteristics of the water and particle velocities are analysed and discussed, which provides the essential knowledge for optimizing the jet performance through optimizing the jetting and abrasive parameters. Mathematical models for the water and particle velocity distributions in an AWJ are finally developed and verified by comparing the predicted jet characteristics with the corresponding CFD simulation data. It shows that the jet characteristics models can yield good predictions for both water and particle velocity distributions in an AWJ. The successful development of these jet dynamic characteristics models is an essential step towards developing more comprehensive mathematical cutting performance models for AWJ cutting and eventually developing the optimization strategies for the effective and efficient use of this advanced manufacturing technology.
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12

Liu, Hua. "A Study of the Cutting Performance in Abrasive Waterjet Contouring of Alumina Ceramics and Associated Jet Dynamic Characteristics." Queensland University of Technology, 2004. http://eprints.qut.edu.au/16110/.

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Abrasive waterjet (AWJ) cutting is one of the most recently developed nontraditional manufacturing technologies. It has been increasingly used in industry owing to its various distinct advantages over the other cutting technologies. However, many aspects of this technology require to be fully understood in order to increase its capability and cutting performance as well as to optimize the cutting process. This thesis contains an extensive literature review on the investigations of the various aspects in AWJ machining. It shows that while considerable work has been carried out, very little reported research has been found on the AWJ contouring process although it is a common AWJ cutting application. Because of the very nature of the AWJ cutting process, the changing nozzle traverse direction involved in AWJ contouring results in kerf geometrical or shape errors. A thorough understanding of the AWJ contouring process is essential for the reduction or elimination of these shape errors. It also shows that a lack of understanding of the AWJ hydrodynamic characteristics has limited the development of cutting performance models that are required for process control and optimization. Accordingly, a detailed experimental investigation is presented in this thesis to study the various cutting performance measures in AWJ contouring of an 87% alumina ceramic over a wide range of process parameters. For a comparison purpose, the study also considers AWJ straight-slit cutting. The effects of process parameters on the major cutting performance measures in AWJ contouring have been comprehensively discussed and plausible trends are amply analysed. It finds that the taper angles on the two kerf walls are in different magnitudes in AWJ contouring. The kerf taper on the outer kerf wall increases with the arc radius (or profile curvature), while that on the inner kerf wall decreases. Moreover, the depth of cut increases with an increase in arc radius and approaches the maximum in straight cutting for a given combination of parameters. The other process variables affect the AWJ contouring process in a way similar to that in straight cutting. The analysis has provided a guideline for the selection of process parameters in the AWJ contouring of alumina ceramics. In order to predict the cutting performance in process planning and ultimately optimize the cutting process, mathematical models for the major cutting performance measures in both straight-slit cutting and contouring are developed using a dimensional analysis technique. The models are then verified by assessing both qualitatively and quantitatively the model predictions with respect to the corresponding experimental data. It shows that the models can adequately predict the cutting performance measures and form the essential basis for developing strategies for selecting the optimum process parameters in AWJ cutting. To achieve an in-depth understanding of the jet dynamic characteristics such as the velocity and pressure distributions inside a jet, a Computational Fluid Dynamics (CFD) simulation is carried out using a Fluent6 flow solver and the simulation results are validated by an experimental investigation. The water and particle velocities in the jet are obtained under different input and boundary conditions to provide an insight into the jet characteristics and a good understanding of the kerf formation process in AWJ cutting. Various plausible trends and characteristics of the water and particle velocities are analysed and discussed, which provides the essential knowledge for optimizing the jet performance through optimizing the jetting and abrasive parameters. Mathematical models for the water and particle velocity distributions in an AWJ are finally developed and verified by comparing the predicted jet characteristics with the corresponding CFD simulation data. It shows that the jet characteristics models can yield good predictions for both water and particle velocity distributions in an AWJ. The successful development of these jet dynamic characteristics models is an essential step towards developing more comprehensive mathematical cutting performance models for AWJ cutting and eventually developing the optimization strategies for the effective and efficient use of this advanced manufacturing technology.
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13

Ammer, Khan Ammer Khan. "Metal to ceramic joining for high temperature applications." Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/5375.

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The phenomenal growth rate for the use of engineering ceramics is attributed to successful scientific responses to industrial demand. These materials are replacing metal and its alloys in diverse applications from cutting tools and heat engine components to integrated circuits. Joining technology plays a vital role in this changing and evolving technology as success and failure comes with breaking new barriers. It is important to improve existing techniques and to develop new techniques that reliably join simple shape components to form complex assemblies or join dissimilar materials such as metal to ceramic. Joining of ceramics is not simple due to their high chemical stability and low coefficient of thermal expansion (CTE). Joining between metal and ceramic is usually carried out at elevated temperatures and upon cooling thermal residual stresses are induced that lead to joint failure or poor strength. Most metal-ceramic joints cannot be used over 500°C primarily due to the low melting temperature of the interlayer. This investigation was concerned with the successful joining for higher temperature applications (above 500°C) of two dissimilar high temperature oxidation and corrosion resistant materials, Fecralloy and silicon nitride. The primary focus was on the effects of process conditions upon the microstructure and mechanical properties of the joint and to also study/identify the joining mechanism. Two novel techniques were employed to join successfully the metal to ceramic. The first was by use of a thin Cu foil that did not remain after joining. Joining occurs by a process that results in partial melting of the Fecralloy interface, where Fe, Cr, Al and Cu reactively infiltrate into the silicon nitride. This liquid mixture causes partial dissolution of the silicon nitride interface, where Si and N diffuse into the Fecralloy. A thin reaction product layer was formed at the silicon nitride interface and our results suggested that this was AIN. The free surface Si and porosity of the silicon nitride along with the eutectic temperatures above 1100°C are all vital for this joining process. The highest average shear strength of a Fecralloy-silicon nitride joint produced by the method was 67.5 MPa. The second route was that of a powder metallurgy one, where cold pressed Ni-Al (1:1 molar) compacts were used to join successfully the Fecralloy to silicon nitride. The formation of NiAl from its constituents is highly exothermic and this is initiated between 500-650°C. The high temperature reached causes partial melting of the Fecralloy interface and dissolution/reactive wetting at the silicon nitride interface. Mostly Fe infiltrates the NiAl improving room temperature ductility, fracture toughness and yield strength. Molten Al from the interlayer reacts and wets the silicon nitride interface with small amount of infiltration and no reaction product forming. The reaction synthesis of NiAl was studied using DTA and TGA, where the effects of Ni particle size and heating rate were investigated. This joining process is highly dependant upon process conditions, the most important of which are applied pressure, heating rate and Ni/A1 particle size. The highest average shear strength attained was 94.30 MPa and this is attributed to good interfacial bonding, high pressure, moderate process temperature and dwell time. The exothermic formation of the NiAl interlayer that is densified and monophase was paramount for this joining process. The Bansal-Doremus kinetic model for evaluating the kinetic parameters from non-isothermal DTA data was shown to be valid. The results obtained were identical to those by other authors who used a different model and approach.
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Kavalír, Vít. "Řezná keramika a její efektivní využití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228619.

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Master’s thesis are concerned with the cutting ceramic materials and its ef-fective usage. The first part of the thesis is focused on the general properties of the cutting ceramics, its history, development, production and description of the various types. This part includes as well a description of the mechanic-physical properties and the potential of the usage for machining. The second part of the work solves the general evaluation of the cutting power. The main issue in the next part is the identification of cutting ceramics range and the selection accor-ding to main world producers. The fourth part deals with the assessments and the comparison of the working conditions for different types of the machined ma-terials. The technical economic assessment shows the potentials in the total pro-duction costs reduction.
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15

Dupák, Libor. "Mikroobrábění nekovových materiálů elektronovým svazkem." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-234155.

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The thesis deals with electron beam micromachining of nonmetallic materials like glass, ceramics and plastics. A brief description of the device on which the experiments were carried out is included; the author has participated on its development. Main topic is experimental study of influence of main electron beam parameters on results of machining. Examined parameters include accelerating voltage, beam current, focusing and speed of machining. Influence of beam deflection is analyzed. Method of sequential machining by repeated passes of the electron beam is presented. Main examined materials are quartz glass, alumina and selected plastics. The usefulness of the technology is shown by several practical applications.
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16

Margarido, Alexandre. "Estudo da influência da força de corte em usinagem a verde nas propriedades mecânicas de cerâmicas sinterizadas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18146/tde-02042012-133133/.

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O estudo trata da medição da força de usinagem a verde de corpos de provas cerâmicos e sua correlação com as propriedades mecânicas após a sinterização. A usinagem a verde é empregada em compactos brutos para conferir formatos sem extremo compromisso com precisão dimensional ou para obter uma pré-forma antes da usinagem de acabamento após sinterização; é extensivamente empregada na usinagem de cerâmicas avançadas. Durante o processo de usinagem a verde os esforços de corte determinam a introdução de defeitos críticos na superfície e são geralmente estes defeitos que governam as propriedades mecânicas das cerâmicas após a sinterização. O trabalho objetiva a elaboração e montagem de um sistema de aquisição de dados das forças de usinagem, e procura identificar o limite de agressividade de corte na manutenção da integridade do corpo de prova com produção econômica. As medidas de torque de usinagem e velocidade periférica do rebolo podem representar um modelo para predizer a associação das forças de usinagem. Corpos de prova cilíndricos foram conformados a 100 e 200 MPa, tratados termicamente após a prensagem e usinados com diferentes parâmetros de corte, sinterizados e ensaiados quanto à resistência mecânica através de compressão e flexão a quatro pontos. Os resultados mostraram a importância do tratamento térmico antes da usinagem acima da temperatura de transição vítrea do ligante para peças prensadas a 100 e 200 MPa. Peças prensadas a 200 MPa e tratadas termicamente foram usinadas sem danos a taxas de remoção de 10.000 \'MM POT.3\'/min com potencia consumida de 1700 W. Com o emprego de um cabeçote com mancais aerostáticos de alta potência e baixo ruído não se detectou a introdução progressiva de defeitos críticos na superfície devido à ação do rebolo, porém se identificou um limite de velocidade de 400 mm/min em função da profundidade de corte que excedeu a resistência mecânica dos corpos de prova comprimidos a 100 MPa, levando a ruptura. A correlação entre potência consumida e taxa de remoção, forneceu informações muito importantes para o projeto de uma máquina de usinagem á verde de produtos cerâmicos em alumina.
The present study deals with the measurement forces of green machining ceramics and their correlation with the mechanical properties after sintering. The green machining is employed in crude compacts either to check raw formats without compromising the extreme dimensional accuracy or to obtain a preform prior to finish machining after sintering, extensively used in the machining of advanced ceramics. During the process of the green machining, cutting forces determine the introduction of the critical defects in the surface, which generally govern the mechanical properties after the sintering of ceramics. The study aims at the development and installation of a system of machining forces data acquisition and also the identification of the limit of cutting aggression to maintain the integrity of the ceramics with economic production. The torque measurements of machining and grinding wheel peripheral speed can represent a model to predict the association of the machining forces. Cylindrical bodies were conformed at 100 and 200 MPa, heat-treated after pressing and machined with different cutting parameters, sintered and tested concerning strength by compression and bending at four points. The results showed the importance of the heat treatment before machining above the glass transition temperature of the binder for the parts pressed at 100 and 200 MPa. Parts pressed at 200 MPa and heat-treated were machined without damage at 10.000 \'MM POT.3\'/min removal rates with power consumption of 1700 W. With the use of a spindle with aerostatic bearings for high power and low noise the gradual introduction of critical defects into the surface was not detected due to the action of the wheel. However a speed limit was identified in function of the depth of the cut, which exceeded the strength of the ceramics compressed at 100 MPa, leading to rupture. The correlation between power consumption and rate of removal provided very important information for the design of a green machining of ceramic products in alumina.
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Grunder, Timothee. "Contribution à l'application de céramiques d'Al2O3 et de 3Y-ZrO2 à structures submicroniques à l'usinage de matériaux dérivés du bois." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD035.

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Les céramiques à base d’Al2O3 et de 3Y-ZrO2 à structures submicroniques présentent, au vu de leurs propriétés physiques et mécaniques, un fort potentiel pour l’usinage de composites en bois. Neuf nuances ont été développées par coulage-gélification (CG) et par pressage isostatique à froid (CIP). Elles ont ensuite été testées en usinage dans des conditions industrielles de coupe. L’objectif de la thèse a été la compréhension, à partir de ces résultats, des mécanismes d’usure, afin d’identifier les propriétés physiques et mécaniques nécessaires pour l’usage d’un matériau nouveau pour cette application. Des outils prototypes de fraisage et de tournage ont été conçus. L’état d’endommagement et les contraintes résiduelles dans la céramique, dus aux étapes de fabrication des prototypes, ont été déterminés. Les résultats des expérimentations de coupe montrent que différents mécanismes opèrent sur l’usure des céramiques. Pour les nuances d’alumine, l’usure de l’arête se fait par arrachement cyclique de grains, tandis que les nuances à base de zircone se déforment plastiquement. Il apparaît que les propriétés physiques, telles que la taille de grain et la densité, sont prédominantes sur les propriétés mécaniques. L’utilisation de céramiques à structure submicronique avec des densités supérieures à 99 % améliore les performances en usinage. C’est la nuance Al2O3-10 % ZrO2 produite par CG qui a montré la meilleure résistance à l’usure. Lors de l'affûtage et de la coupe, l'oxyde de zirconium non stabilisé opère un changement de phase qui induit des contraintes de compression au sein de la microstructure et augmente ainsi la résistance micromécanique des joints de grain
High mechanical properties of sub-μm grain Al2O3 and 3Y-ZrO2 present high potential for the cutting of wood-based materials. Nine grades were produced by gelcasting (GC) and cold isostatic pressing (CIP). They were tested in real industrial conditions. From those results, this thesis’ aim was to highlight the wear mechanisms in cutting, and then deduce major physical and mechanical properties that are task of material development. Consequently, prototypes for cutting trials have been developed. As a result, the manufacturing of prototype tools, X-Ray diffraction, analytical and numerical investigations were performed to quantify residual stress that occurred in ceramic. Observation of the results of experimentations in machining showed different wear modes. For alumina’s grade, single grain pull-out was the main wear mechanism of the cutting edge, while microplastic deformation occurred in zirconia’s composition. Physical properties of ceramic structure, like grain size and density, are more important than mechanical properties. To improve cutting lifetime, density must be higher than 99%, with a structure with sub-μm grain size. It appeared that there was a predominant role of micromechanical stability while cutting abrasive materials. Fracture toughness or thermal shock resistance seem to have marginal influence when ceramic were produced by low-defect process like GC. Regarding all ceramic grades the Al2O3-10ZrO2 made by GC showed the highest wear resistance in machining. Unstabilized zirconia brought micromechanical stability between grains of the cutting edge while working
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18

Jurán, Antonín. "Efektivní obrábění nových konstrukčních keramických materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228424.

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The objective of this diploma thesis are new design materials in a view of their structure, properties, manufacture,partitions, applications and possibili-ties of effective machining them Ceramics are used in the field of design applications more often than before. They are in form of compact parts and in form of thin coatings on the surface of metal parts. Fast development of constructive applications requires the same progress rate of machining ma-chines innovations and development of new methods of effective machining these materials, too. The aim is to produce parts of demanded shapes, dimensions and surface quality at affordable costs. Ceramics guarantee long terming durability and reliability. The evaluation of ceramics grinding tests from the point of view of cutting forces and surface quality of the machined faces are presented in the last part of the diploma thesis.
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Khamsehzadeh, Houshang. "Behaviour of ceramic cutting tools when machining superalloys." Thesis, Online version, 1991. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.293915.

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20

Hassine, Nabile. "Microwave-assisted synthesis of non-oxide ceramic powders." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240494.

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21

Contarato, Flavien. "Conception d'outils capables d'usiner les matériaux dérivés du bois : caractérisation du comportement à l'usinage d'outils à base de céramiques." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD028.

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Six nuances de céramique à base d’alumine et de zircone sont étudiées en tant que matériau de coupe pour l’usinage des panneaux composites dérivés du bois. L’objectif est de définir la durée de vie de l’outil céramique par rapport au référentiel qu’est le carbure de tungstène et d’en déterminer leur comportement à l’usinage. Le procédé de fabrication, la préparation en insert de coupe et la tenue en usinage des céramiques sont étudiés. Des analyses cristallographiques, associées à la caractérisation des propriétés mécaniques, sont effectuées afin de déterminer l’état du matériau. Deux essais d’usinage sont mis en place : le premier pour définir le système de fixation des inserts et la géométrie de l’outil via un plan d’expériences, le second pour déterminer le procédé d’élaboration de la céramique qui donne la meilleure durée de vie de d’outil. Elle est définie en fonction de critères de qualité comme la superficie des éclats sur le décor et la rugosité de la surface usinée. Les céramiques élaborées par procédé sol-gel après 9 800 m de distance linéaire usinée présentent la meilleure durée de vie, comparativement au carbure de tungstène qui n’a effectué que 8 050 m
Six grades of ceramics composed by alumina and zirconia have been studied as a cutting material to cut composites wood panels. The first aim is to define the ceramic tool’s lifetime in comparison with the cemented tungsten carbide which is our frame of reference. The second one is to determine its cutting behaviour. The manufacturing process, the preparation of the cutting inserts and the wear resistance of the ceramics have been studied. Crystallographic analyses combined with mechanical properties characterization were used to determine the state of the material. Two machining tests have been implemented. The first one to define the clamping system of the cutting inserts and the tool geometry by using an experimental designs tool. The second one to determine the manufacturing process of the ceramic which will gives the best cutting tool’s lifetime. It is defined quality criteria like the area of delamination of the wood panels and the rugosity of the machined surface. Ceramics manufactured with the gel-casting process showed after 9,800 m of cutting distance the best cutting tool’s lifetime, in comparison with cemented tungsten carbide which achieved only 8,050 m
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Abrão, Alexandre Mendes. "The machining of annealed and hardened steels using advanced ceramic cutting tools." Thesis, University of Birmingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249408.

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Varhaník, Matúš. "Obrábění těžkoobrobitelných materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-379004.

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General perspective of this diploma thesis was aimed at machining of hard-to-machine materials. Theoretical part contains division and specification of these types of materials. Ways of classification and evaluation were also listed. Causes of worsened machinability were defined with the design of possible technological solutions, which eliminates these features. The main target of experimental part was turning nickel-based superalloy Inconel® 718 with the purpose of increase process productivity. Knowledge about appropriate types of cutting tool material and his coating were necessary for process optimization. It was achieved by replacing reference cutting tool material (coated carbide inserts) with SiAlON ceramic. Cutting tool edge was tested with an intention to discover appropriate deal between tool life and volume of material removed. Measured cutting forces, generated by machining of reference and optimize technology, were processed by using simulation software. Total deformation of workpiece material was statistically evaluated. The conclusion of diploma thesis is technical-economic evaluation of both options.
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MARCHI, JULIANA. "Estudo de sinterizacao de ceramicas a base de nitreto de silicio utilizando-se como aditivos oxidos de cerio e aluminio." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10744.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Kresa, Jakub. "Studie obrábění keramických materiálů broušením." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231435.

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This thesis is focused on ceramics materials in terms of their partition, properties, structure, manufacture and methods of their possible machining. The first part of this thesis is devoted to the distribution of ceramics materials, their structure, properties, and methods of production. Currently, ceramics materials are increasingly used in structural (engineering) applications therefore we deal with methods of effective machining of ceramic materials, to achieve part of the required shape, dimensions and surface quality. The evaluation of ceramic grinding test from the point of view of cutting forces and surface quality of the machined faces are presented in the last part of the thesis. The tested materials have been provided by company SEEIF Ceramics a.s.
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Bonney, John. "High-speed machining of nickel-base, Inconel 718, alloy with ceramic and coated carbide cutting tools using conventional and high-pressure coolant supplies." Thesis, London South Bank University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410701.

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The first part of this study involve an evaluation of the performance of recently developed nano-grain size ceramic tool materials when machining nickel base, Inconel 718, with conventional coolant flow in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition. The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. It is also evident that chemical compositions of the tool materials played significant role in their failure. The alumina base ceramics performed better than the silicon nitride base ceramics. Severe abrasion wear was observed on both rake and flank faces of the cutting tools while cutting forces increased with increasing cutting speed when machining with the silicon nitride base nano-ceramic tools. This is probably due to the lower superplastic flow temperature of the nitride base nano-ceramics. The second part of this study involve turning of Inconel 718 with commercially available ceramic and PVD coated carbide tools with conventional and high-pressure coolant supplies at cutting speeds up to 300 and 60 m min" respectively. Increasing the coolant pressure results in shorter tool life when machining Inconel 718 with ceramic tools, suggesting that the high-pressure coolant supply reduces temperature at the cutting zone below a critical level where ceramic tools can perform satisfactorily. The inadequate fracture toughness of ceramic tools makes them more susceptible to failure by mechanical action such as notching at the depth of cut line and premature fracture. The notch wear rate increases with higher coolant supply pressure due to significant erosion of the tool material by the high-pressure coolant jet. Machining Inconel 718 with a triple PVD coated (TiCNI AI20iTiN) carbide tool at speeds up to 60 mlmin using conventional and various high coolant pressures, up to 203 bar was found to be encouraging. The test results show that acceptable surface finish and improved tool life can be achieved when machining Inconel 718 with high coolant pressures. Compared to conventional coolant supplies, tool life improved as much as 7 folds when machining at 203 bar coolant pressure at high speed conditions. Tool life generally increased with increasing coolant supply pressure due to the ability of the high-pressure coolant to lift the chip and gain access closer to the cutting interface. Chip breakability during machining is dependent on the depth of cut, feed rate and cutting speed employed as well as on the coolant pressure employed. Machining Inconel 718 with lower coolant pressures did not produce chip segmentation. Tool wear increased gradually with prolong machining with high coolant pressures. Nose wear was the dominating tool failure mode when machining with coated carbide tools due probably to a reduction in the chip-tool and tool-workpiece contact length/area. SEM micrographs of the machined surfaces show that micro-pits are the main damage to the machined surfaces. Microhardness analysis show evidence of hardening of the top machined surfaces. In most cases the microhardness readings tend to approach the hardness of the base material at 0.25 mm under rough and 0.2 mm under finish machining below the machined surface. This is due to the austenitic structure of Inconel 718 which promote work hardening when machining as a result of the high temperature generated at the cutting interfaces. The hardening effect decreased under finishing conditions and with increasing coolant pressures up to 203 bar as the coolant gain access closer to the cutting interfaces, thus minimising the cutting interface temperature. Analysis of the microstructure shows that severe plastic deformation occurred when machining with conventional coolant supply than with highpressure coolant supplies. There was also mild plastic deformation under finish machining. Surface damage or phase transformation was absent when machining Inconel 718 under highpressure coolant supplies. Generally the surface integrity of the finish machined surface is in accordance with CME 5043.
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27

Reiter, Milan. "Obrábění žáruvzdorných keramických materiálů frézováním." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231462.

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Diploma thesis is focused on machining of refractory ceramics materials. The theoretical part describes the division of ceramics materials, their structure, manufacture and properties. This part also contains the division of refractory ceramics. In the second chapter, of ceramics materials are described machining. The latest chapter is focused on analyzing the machinability of ceramics materials R - SLI - K. During the experiment, cutting conditions were changed and cutting forces were checked. Then surface roughness was measured and tool wear was observed.
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Rudel, Václav. "Obrábění keramických materiálů frézováním." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232055.

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In the diploma thesis dividing of ceramic materials is made, their bonds and other attributions, which define ceramic materials. There is also described how ceramic materials are manufactured and the thesis is including information about machining ceramic materials. In the experimental part sample of ceramic material R-S67K was machined by milling. During the experiment cutting forces were measured and roughness of surface after finishing, these data were finally evaluated.
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Melhaoui, Ahmed. "Contribution à l'étude de l'usure d'outil de coupe en usinage assisté par laser et à l'usinabilité d'une céramique à base d'oxyde de zinc." Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0513.

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Définir une nouvelle génération d'outil de coupe adapté à l'UAL, maitriser les conditions de coupe pour différents types de matériaux, comprendre les phénomènes de l'interaction laser-matériau et disposer d'une base de connaissances capable de nous fournir les éléments de calcul nécessaires à la conception ou la transformation de centres d'usinage classique en centres d'usinage assisté par laser sont des étapes indispensables à l'industrialisation du procéde. Le travail qui va d'être présenté a pour objectif d'enrichir la base de connaissance du procède et de mettre en place une méthode d'optimisation capable de nous fournir une estimation de l'usure en temps réel, et cela, à travers l'analyse de l'émission acoustique générée par le contact outil - pièce et par les efforts de coupe. Dans un premier temps, l'étude porte sur l'usinabilité d'une céramique à base d'oxyde de zinc. Il est montré que le fait d'assister la coupe avec un faisceau laser améliore nettement l'état de surface, du fait de la réduction des efforts de coupe et de l'usure de l'outil. Dans un deuxième temps, un planétaire à queue en acier 16MnCr5 utilise par Renault est étudié. L’étude est centrée sur l'outil de coupe. Il a été démontré que la durée de vie des outils de coupe est largement augmenter par rapport a l'UC. Les premiers résultats expérimentaux obtenus montrent que, la puissance laser ou la combinaison de la puissance laser avec un autre paramètre, joue sur le comportement de l'usure. Une étude approfondie reste à faire sur ce point. Enfin, une étude d'optimisation de l'usure en fonction des paramètres du signal de l'émission acoustique généré lors du contact outil - pièce et par les efforts de coupe a été ébauché. Cette étude est basée sur un modèle autorégressif permettant de calculer certains coefficients qui conduisent à l'estimation de la valeur de l'usure. Le contrôle de l'usure en temps réel peut donc se faire simplement à travers le signal généré par le contact pièce - outil et les efforts appliques. Ce travail est un pas de plus franchi vers l'amélioration des connaissances du procédé par le biais de l'élargissement au mode d'usure des outils de coupe, ce qui est nouveau. C’est également le début d'un long travail de recherche qui aboutira a la définition de l'outil le plus adapté à la coupe avec assistance laser
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Lazárková, Veronika. "Řezná keramika a její efektivní využití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228781.

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Thesis is focused on ceramic cutting tools in terms of their labeling, composition, use and production of well-known manufacturers cutting tools. Part of this work is comparison of the selected range of manufacturers.
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31

Strehler, Claudia. "Development of near net shaped Si3N4/SiC composites with optimised grain boundary phase for industrial wood machining." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-71329.

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The introduction of ceramics into the market of wood cutting tools has failed so far due to the generally low toughness of ceramics which is causing brittle failure of the cutting edge. A feasibility study showed that Si3N4/SiC composites with fine elongated β-Si3N4 grains are a promising material for industrial wood machining and outperform commercial standard tungsten carbide tools in terms of lifetime. However, they were produced by hot pressing followed by very costly diamond cutting and grinding. The costs associated with the above production route are too high for an industrial viability. In this thesis Si3N4/SiC composites suitable for industrial wood milling are produced by a near net shape processing route including gas pressure sintering. These newly developed tools show less abrasive wear and consequently twice as long lifecycles than commercial standard tungsten carbide tools. Microscopic properties determine the performance of the Si3N4/SiC cutting tools. Therefore, an adequate selection of sintering additives is crucial. 12 wt% sintering additives are included in the composite as a combination of Al2O3 and the refractory oxides La2O3 and Y2O3. Important for the production of effective Si3N4/SiC wood cutting tools is the formation of a partly crystalline silicate phase within the multiple grain junctions during the final treatment by hot isostatic pressing. The use of MgO as a sintering additive for facilitating the densification of the Si3N4 ceramics inhibits the formation of the favourable silicate phase and must be avoided for the production of these wood cutting tools.
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Djenkal, Djamal. "Al2O3-AlON-SiC, composite céramique pour la coupe : élaboration et caractérisations mécaniques." Grenoble INPG, 1996. http://www.theses.fr/1996INPG4207.

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Les outils de coupe ceramiques permettent, par l'augmentation des vitesses de coupe, l'amelioration des rendements d'usinage. Ce travail a consiste a developper un composite a matrice alumine 80- oxynitrure d'aluminium 20 vol. Pourcents renforce par du carbure de silicium sous deux morphologies: poudre et plaquette. Les etudes ont porte sur les ameliorations du procede de fabrication et l'evaluation du comportement en frottement et en coupe d'un acier dur (z38cdv5) et un superalliage base nickel (inconel 718). Outre l'interet de la formation in situ de l'oxynitrure d'aluminium (reaction alumine-nitrure d'aluminium) au cours du frittage sur la densification finale, il est montre qu'une homogeneisation par attrition conduit a un certain renforcement de la matrice. Les proprietes mecaniques du materiau a poudre optimise sont maintenues jusqu'a 1000c. Concernant le composite a plaquette, on observe une reactivite identique a celle du composite a poudre, mais a une temperature plus basse. On obtient les valeurs maximales de tenacite (7 mla. M) pour un diametre de moyen de 8 microns et une teneur en plaquettes de 20 vol. Pourcents. Dans les conditions de frottement testees (faible pression), l'usure des composites face a l'acier est negligeable, face a l'inconel l'usure n'est plus negligeable et depend de la granularite de sic et du taux d'oxynitrure. Les essais de coupe, realises a l'ecole centrale de nantes, laboratoire materiaux, montrent l'interet des composites renforces par la poudre pour le tournage d'acier de haute dureté
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Bruno, Danver Messias. "Estudo da aplicação de insertos de cerâmica avançada na usinagem de ultraprecisão em aços endurecidos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18145/tde-27092013-105238/.

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O objetivo principal desse trabalho é investigar a aplicação de cerâmica á base de Zirconia em ferramentas de corte na usinagem de aço temperado (VND) utilizando um torno de ultraprecisão. Foram analisados dois tipos de composições de cerâmicas com estrutura cristalina diferentes, sendo elas: monoclínica e tetragonal. A diferença destas estruturas é devido à adição de Ytria. A fase monoclínica não contém Ytria em sua composição, enquanto, a fase tetragonal é obtida com Ytria (\'Y IND.3\') (chamada zirconia parcialmente estabilizada com Ytria). A fase tetragonal apresenta uma resistência elevada ao impacto junto com alta dureza (1800 kgf/\'MM POT.2\') quando comparada com a fase monoclínica que apresenta alta dureza mas menor tenacidade. Devido a este fato, esses materiais têm chamado à atenção dos pesquisadores para a usinagem de aços endurecidos. A geração de superfície é influenciada por diversos fatores, sendo eles: material peça, condições de corte, erros macro geométrico, erros de micro geometricos e do estado da aresta da ferramenta. Na usinagem de ultraprecisão a alta rigidez e vibração/trepidação máquina ferramenta é usada para evitar erros de micro geometria e macro geometria que conseqüentemente são transferidos para superfície da peça. Neste trabalho, devido ao fato de se usar um torno de ultraprecisão é possível afirmar que o perfil da rugosidade é gerado pela replicação do perfil da aresta da ferramenta de corte para a superfície da peça. A rugosidade da superfície foi medida com um perfilometro óptico com resolução de 0,1 nm. Os resultados mostraram que a rugosidade da superfície obtida após os testes de usinagem com as ferramantas de cerâmicas chegou á valores em torno de 0,140 microns, o que equivale ao acabamento com processo de retificação. Outro aspecto importante refere-se ao desgaste das ferramentas que, conseqüentemente, tem uma grande influência nos resultados obtidos. As ferramentas de corte foram analisadas antes e depois da usinagem por microscópio eletrônico de varredura. Verificou-se que as ferramentas de corte na fase tetragonal apresentaram desgaste do tipo cratera na aresta da ferramenta enquanto a aresta da ferramenta monoclínica apresentou desgaste do tipo lascamento.
The main objective of this work is to investigate the application of a ceramic composite of Alumina-Zirconia cutting tools inserts in the machining of hardened steel (VND) in an ultraprecision lathe. Two different ceramic compositions with different crystalline structure were tested, to know: monoclinic and tetragonal. The difference in these structures is due the addition of Yttrium. The monoclinic phase has no Yttrium in its composition while the tetragonal phase is obtained with Ytrium (\'Y IND.3\') (named partially stabilized zirconium). The tetragonal phase presents a high impact toughness along with high hardness (1800 kgf/\'MM POT.2\') when compared to the monoclinic phase which presents high hardness but lower toughness. Due to this fact, these materials have draw attention of researchers in the field of machining of hardened steels. The surface generation is influenced by several factors, to know: workpiece material, cutting conditions, macro geometry errors, micro geometry errors and the sharpness of the cutting edge. In ultraprecision machining, a high stiffness and chatter/vibration free machine tool is used in order to avoid common macro and micro geometry errors replicated into the workpiece surface. In this case, it is possible to assert that the roughness profile is generated by the replication of the cutting tool edge profile to the workpiece surface. The surface roughness was measured by an optical profiler with resolution of 0,1 nm. The results showed that the surface roughness obtained after machining tests with these ceramic inserts were in the range of 0,140 micrometers, which is in the same range of roughness obtained by the grinding process. Another important aspect refers to the wear of the ceramic inserts which has direct influence in the performance as a cutting tool material. The cutting inserts were evaluated before and after machining by scanning electron microscope. It was found that the tetragonal phase cutting tools presented crater wear on the rake face while the monoclinic phase presented cutting edge chipping as the main main type of wear.
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34

Silva, Moacir Guilhermino da. "Avalia??o da incorpora??o combinada dos res?duos de cascalho de perfura??o de po?o de petr?leo e de polimento do porcelanato em cer?mica vermelha." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12861.

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Among the industries, those that produce ceramic porcelain for use in construction industry and oil, during the exploration and production period, play an important role in the production of waste. Much research has been carried out both by academia and the productive sector, sometimes reintroducing them in the same production line that generated them, sometimes in areas unrelated to their generation, as in the production of concrete and mortar for the construction, for example, but each one in an isolated way. In this research, the aim is to study the combined incorporation of the waste drill cuttings of oil well and the residue of the polishing of porcelain, generated in the final stage of finishing of this product in a clay matrix, for the production of red pottery, specifically bricks, ceramic blocks and tiles. The clay comes from the municipality of S?o Gon?alo, RN, the drilling waste is from the Natal basin, in Rio Grande do Norte, and the residue of the polishing proceeds from a ceramic porcelain of the State of Para?ba. For this purpose, we used a mixture of a plastic clay with a non-plastic, in a ratio of 50% each, settling formulations with the addition of these two residues in this clay matrix. In the formulations, both residues were incorporated with a minimum percentage of 2.5% and maximum of 12.5%, varying from 2.5% each, in each formulation, which the sum of the waste be no more than 15%. It should be noted that the residue of the polishing of ceramic porcelain is a IIa class (not inert). The materials were characterized by XRF, XRD, TG, DTA, laser granulometry and the plasticity index. The technological properties of water absorption, apparent porosity, linear shrinkage of burning, flexural tensile strength and bulk density were evaluated after the sintering of the pieces to 850 ?C, 950 ?C and 1050 ?C, with a burning time of 3 hr, 3 hr and 30 minutes, and 3 hr and 50 minutes, respectively, with a heating rate of 10 ?C/minute, for all formulations and landing of 30 minutes. To better understand the influence of each residue and temperature on the evaluated properties, we used the factorial planning and its surfaces of response for the interpretation of the results. It was found that the temperature has no statistical significance at a 95% of reliability level in flexural tensile strength and that it decreases the water absorption and the porosity, but increases the shrinkage and the bulk density. The results showed the feasibility of the desired incorporation, but adjusting the temperature to each product and formulation, and that the temperatures of 850 ?C and 950 ?C were the one that responded to the largest number of formulations
A ind?stria de produ??o de porcelanatos para uso na constru??o civil e a do petr?leo, na fase de explora??o e produ??o, exercem um papel importante na produ??o de res?duos. Muitas pesquisas t?m sido realizadas tanto pela academia quanto pelo setor produtivo, ora reintroduzindo esses res?duos na mesma linha de produ??o que os gerou, ora em setores alheios ao de sua gera??o, como na produ??o de concretos e argamassas para a constru??o civil, por exemplo, mas cada um de forma isolada. O objetivo desta pesquisa ? estudar a incorpora??o combinada do res?duo de cascalho de perfura??o de po?o petrol?fero e do res?duo do polimento do porcelanato, gerado na fase de acabamento final do produto, numa matriz argilosa, para a produ??o de cer?mica vermelha - especificamente tijolos, blocos cer?micos e telhas. A argila utilizada ? oriunda do munic?pio de S?o Gon?alo do Amarante, RN; o res?duo de perfura??o, da bacia potiguar, no Rio Grande do Norte; e o do polimento ? de uma cer?mica de porcelanato do Estado da Para?ba. Utilizou-se a mistura de uma argila pl?stica com uma n?o pl?stica, numa propor??o de 50 % de cada uma (que ? o percentual de mistura adotado na cer?mica fornecedora dessa argila), estabelecendo-se formula??es com a incorpora??o dos dois res?duos nessa matriz argilosa. Nas formula??es, os dois res?duos foram incorporados com um percentual m?nimo de 2,5 % e m?ximo de 12,5 %, variando-se em 2,5 % cada um, em cada formula??o, de modo que a soma dos res?duos fosse no m?ximo 15 %. ? oportuno registrar que o res?duo do polimento do porcelanato ? de classe IIa (n?o inerte). Os materiais foram caracterizados por FRX, DRX, TG, DTA, granulometria a laser e pelo ?ndice de plasticidade. As propriedades tecnol?gicas de absor??o de ?gua, porosidade aparente, retra??o linear de queima, tens?o de ruptura ? flex?o e massa espec?fica aparente, foram avaliadas ap?s a sinteriza??o das pe?as a 850 ?C, 950 ?C e 1050 ?C, com ciclo de queima de 3 h , 3 h e 30 min e 3 h e 50 min, respectivamente, com taxa de aquecimento de 10 ?C/min. e patamar de 30 min., para todas as formula??es. Para melhor compreender-se a influ?ncia de cada res?duo e de cada temperatura nas propriedades avaliadas, utilizou-se o planejamento fatorial e suas superf?cies de resposta para interpreta??o dos resultados. Verificou-se que a temperatura n?o tem signific?ncia estat?stica no n?vel de 95 % de confiabilidade na tens?o de ruptura ? flex?o e que ela diminui a absor??o de ?gua e a porosidade, mas aumenta a retra??o e a massa espec?fica aparente. Os resultados mostraram a viabilidade da incorpora??o pretendida, adequando-se a temperatura a cada produto e cada formula??o, e as temperaturas de 850 ?C e 950 ?C foram as que atenderam ao maior n?mero de formula??es
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35

Liu, Jian. "Experimental study and modeling of mechanical micro-machining of particle reinforced heterogeneous materials." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5408.

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This study focuses on developing explicit analytical and numerical process models for mechanical micro-machining of heterogeneous materials. These models are used to select suitable process parameters for preparing and micro-machining of these advanced materials. The material system studied in this research is Magnesium Metal Matrix Composites (Mg-MMCs) reinforced with nano-sized and micro-sized silicon carbide (SiC) particles. This research is motivated by increasing demands of miniaturized components with high mechanical performance in various industries. Mg-MMCs become one of the best candidates due to its light weight, high strength, and high creep/wear resistance. However, the improved strength and abrasive nature of the reinforcements bring great challenges for the subsequent micro-machining process. Systematic experimental investigations on the machinability of Mg-MMCs reinforced with SiC nano-particles have been conducted. The nanocomposites containing 5 Vol.%, 10 Vol.% and 15 Vol.% reinforcements, as well as pure magnesium, are studied by using the Design of Experiment (DOE) method. Cutting forces, surface morphology and surface roughness are characterized to understand the machinability of the four materials. Based on response surface methodology (RSM) design, experimental models and related contour plots have been developed to build a connection between different materials properties and cutting parameters. Those models can be used to predict the cutting force, the surface roughness, and then optimize the machining process. An analytical cutting force model has been developed to predict cutting forces of Mg-MMCs reinforced with nano-sized SiC particles in the micro-milling process. This model is different from previous ones by encompassing the behaviors of reinforcement nanoparticles in three cutting scenarios, i.e., shearing, ploughing and elastic recovery. By using the enhanced yield strength in the cutting force model, three major strengthening factors are incorporated, including load-bearing effect, enhanced dislocation density strengthening effect and Orowan strengthening effect. In this way, the particle size and volume fraction, as significant factors affecting the cutting forces, are explicitly considered. In order to validate the model, various cutting conditions using different size end mills (100 &"181;m and 1 mm dia.) have been conducted on Mg-MMCs with volume fraction from 0 (pure magnesium) to 15 Vol.%. The simulated cutting forces show a good agreement with the experimental data. The proposed model can predict the major force amplitude variations and force profile changes as functions of the nanoparticles' volume fraction. Next, a systematic evaluation of six ductile fracture models has been conducted to identify the most suitable fracture criterion for micro-scale cutting simulations. The evaluated fracture models include constant fracture strain, Johnson-Cook, Johnson-Cook coupling criterion, Wilkins, modified Cockcroft-Latham, and Bao-Wierzbicki fracture criterion. By means of a user material subroutine (VUMAT), these fracture models are implemented into a Finite Element (FE) orthogonal cutting model in ABAQUS/Explicit platform. The local parameters (stress, strain, fracture factor, velocity fields) and global variables (chip morphology, cutting forces, temperature, shear angle, and machined surface integrity) are evaluated. Results indicate that by coupling with the damage evolution, the capability of Johnson-Cook and Bao-Wierzbicki can be further extended to predict accurate chip morphology. Bao-Wierzbiki-based coupling model provides the best simulation results in this study. The micro-cutting performance of MMCs materials has also been studied by using FE modeling method. A 2-D FE micro-cutting model has been constructed. Firstly, homogenized material properties are employed to evaluate the effect of particles' volume fraction. Secondly, micro-structures of the two-phase material are modeled in FE cutting models. The effects of the existing micro-sized and nano-sized ceramic particles on micro-cutting performance are carefully evaluated in two case studies. Results show that by using the homogenized material properties based on Johnson-Cook plasticity and fracture model with damage evolution, the micro-cutting performance of nano-reinforced Mg-MMCs can be predicted. Crack generation for SiC particle reinforced MMCs is different from their homogeneous counterparts; the effect of micro-sized particles is different from the one of nano-sized particles. In summary, through this research, a better understanding of the unique cutting mechanism for particle reinforced heterogeneous materials has been obtained. The effect of reinforcements on micro-cutting performance is obtained, which will help material engineers tailor suitable material properties for special mechanical design, associated manufacturing method and application needs. Moreover, the proposed analytical and numerical models provide a guideline to optimize process parameters for preparing and micro-machining of heterogeneous MMCs materials. This will eventually facilitate the automation of MMCs' machining process and realize high-efficiency, high-quality, and low-cost manufacturing of composite materials.
Ph.D.
Doctorate
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
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36

Marques, Armando. "Torneamento de Inconel 718 com aplicação de lubrificantes sólidos." Universidade Federal de Uberlândia, 2015. https://repositorio.ufu.br/handle/123456789/14776.

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Fundação de Amparo a Pesquisa do Estado de Minas Gerais
The nickel-based superalloys have a high mechanical strength which remains at elevated temperature, high creep and fatigue resistances and excellent oxidation resistance. This makes these alloys highly recommended for use in high temperature working environments such as mechanical components for the aerospace industry. However, these characteristics are major problems when machining them, as it promotes high heat generation in the flow zone, resulting in the development of high wear rates on the cutting tools. In order to reduce the problems caused by the high temperatures generated, the application of a cutting fluid, when possible, is essential to reduce friction at the chip-tool-workpiece interfaces and lower the temperatures in the cutting zone. Seeking to further increase in the efficiency of cutting fluids during machining of nickel alloys, this work presents a study of the influence of solid lubricants, graphite and molybdenum disulphide (MoS2) mixed to a vegetal based cutting fluid, applied by conventional method (flooding) and minimal quantity of fluid - MQF in turning of Inconel 718 with carbide and ceramic (mixed, whisker and SiAlON) tools. When turning with cemented carbide tools the addition of graphite to the cutting fluid provided the best results, while with ceramic tools MoS2 presented the best performance. The life of the carbide tool had an average increase above 200% in conventional flooding application of cutting fluid when compared to MQF, regardless the addition of solid lubricant. The addition of solid lubricants promoted an increase in the life of whisker and SiAlON tools. The flank wear was dominant for cemented carbide tools and SiAlON ceramics, while for whisker and mixed ceramics the notch wear was predominant. Attrition and diffusion wear mechanism were observed in all evaluated conditions. The addition of solid lubricant to the cutting fluid provided significant improvements in the surface roughness values for most of the evaluated conditions. However, there were no significant changes in the machining forces and cutting temperature. The residual stress was tensile and compression, depending on the fluid application method. Overall, the addition of solid lubricant showed no significant differences.
As superligas à base de níquel apresentam alta resistência mecânica que se mantém em elevadas temperaturas, altas resistência à fluência e à fadiga e excelente resistência a oxidação. Isso torna estas ligas altamente recomendadas para utilização em ambientes que trabalham a altas temperaturas, como por exemplo na fabricação de componentes mecânicos para a indústria aeroespacial. Entretanto, esta característica representa um grande problema quando elas são usinadas, pois promove elevada geração de calor na zona de fluxo, implicando no desenvolvimento de altas taxas de desgaste da ferramenta de corte. A fim de reduzir os problemas causados pelas altas temperaturas geradas, a aplicação de um fluido de corte, quando possível, é essencial, proporcionando redução do atrito na interface cavaco-ferramenta-peça e menores temperaturas na zona de corte. Na busca de aumentar ainda mais a eficiência dos fluidos de corte na complexa usinagem das ligas de níquel, este trabalho apresenta um estudo da influência dos lubrificantes sólidos grafite e bissulfeto de molibdênio (MoS2) misturado a um fluido de corte de base vegetal, aplicados pelo método convencional (jorro) e mínima quantidade de fluído MQF, no torneamento do Inconel 718, com ferramentas de metal duro e cerâmicas (mista, whisker e SiAlON). No torneamento com ferramentas de metal duro a adição de grafite ao fluido de corte proporcionou os melhores resultados, enquanto que no torneamento com ferramentas cerâmicas, foi o MoS2 que apresentou melhor desempenho. A vida da ferramenta de metal duro teve um incremento acima de 200% na usinagem convencional (jorro) quando comparado com a usinagem por MQF, sem considerar a adição do lubrificante sólido. A adição de lubrificantes sólidos promoveu um incremento na vida das ferramentas whisker e SiAlON. O desgaste de flanco foi predominante para as ferramentas de metal duro e cerâmica SiAlON, enquanto que nas cerâmicas whisker e mista o desgaste de entalhe foi predominante. Os mecanismo de desgaste de attrition e difusão foram observados em todas as condições avaliadas. A adição de lubrificante sólido ao fluido de corte proporcionou melhorias significativas nos valores da rugosidade para a maioria das condições avaliadas. No entanto, não se observou mudanças significativas nas forças e temperatura de usinagem. As tensões residuais foram de tração e compressão, dependendo do método de aplicação do fluido. No geral, a adição do lubrificante sólido não apresentou diferenças significativas.
Doutor em Engenharia Mecânica
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37

Kondo, Marcel Yuzo. "Análise do processo de torneamento da superliga Vat 32® com ferramentas de corte experimentais e comerciais /." Guaratinguetá, 2019. http://hdl.handle.net/11449/182500.

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Orientador: Manoel Cleber de Sampaio Alves
Resumo: A superliga de níquel VAT 32® foi desenvolvida como um substituto da liga UNS N07751 (Inconel 151) na fabricação de válvulas automotivas para motores de combustão interna de alto desempenho. A formação de carbonetos de nióbio confere a esta liga elevada resistência ao desgaste, desejada na aplicação em válvulas automotivas, criando-se, porém, uma maior dificuldade na usinagem deste material. Este trabalho estudou o torneamento da liga VAT 32® com quatro tipos de ferramentas de corte. São elas insertos de metal duro com diferentes revestimentos, Ti(C,N) + Al2O3 pelo processo de deposição química de vapor (chemical vapor deposition – CVD), e revestimento de Ti-Al-Si-N pelo processo de deposição física de vapor (physical vapor deposition – PVD), pastilhas de nitreto cúbico de boro (cBN) e pastilhas experimentais de Al2O3 + MgO. Através do método de Taguchi de planejamento experimental, foram obtidas as combinações e os efeitos principais dos parâmetros velocidade de corte, avanço da ferramenta, profundidade de usinagem e tipo de lubrificação (seco ou em abundância) para otimizar cada uma das variáveis respostas, sendo elas potência de usinagem, desgaste das ferramentas, qualidade superficial das peças usinadas, e os sinais de emissão acústica e vibração do processo. Foram obtidos também, através da análise da razão sinal-ruído (S/N) de Taguchi, a composição dos parâmetros de corte em que o processo apresentou menor variabilidade das características de qualidade, o chamado proces... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: VAT 32® is a nickel based super alloy developed to substitute UNS N07751 alloy in production of automotive valves for high performance internal combustion engines. The formation of niobium carbides gives to this alloy a high resistance to wear, desired in the application in automotive valves, creating however, a greater difficulty in the machining of this material. This thesis aimed the study of VAT 32® turning with four different cutting tools. The tested tools were Ti(C,N)+Al2O3 coated by chemical vapor deposition (CVD) carbide inserts, Ti-Al-Si-N coated by physical vapor deposition (PVD) carbide inserts, cubic boron nitrite (cBN) inserts and experimental Al2O3+MgO ceramic inserts. Optimal combination of the cutting parameters and main effects of the factors speed of cutting, tool feed, depth of cutting and lubrication condition (dry and abundant) in turning of VAT 32® were found using Taguchi’s method as a design of experiment (DOE). The analyzed response variables were machining power, tool wear, surface quality of the machined pieces, chips format and acoustic emission and vibration signals of the process. It was also obtained in this work the robust process with the analysis of signal to noise ratio (S/N) where cutting parameters for smaller process variability were found. Finally, the multi-objective optimization method called Grey Relational Analysis (GRA) was used to find optimal cutting conditions for each tested tools. These optimal conditions were used in a tool l... (Complete abstract click electronic access below)
Doutor
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38

Di, Maio Yoan. "Etude de l'interaction laser-matière en régime d'impulsions ultra-courtes : application au micro-usinage de matériaux à destination de senseurs." Phd thesis, Université Jean Monnet - Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-00994999.

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Le laser à impulsions ultra-courtes constitue un procédé innovant et très avantageux pour la découpe de céramiques piézoélectriques PZT. Grâce à un fort confinement spatiotemporel de l'énergie au cours de l'interaction, ce système minimise les dégâts collatéraux et préserve l'intégrité physique du matériau sur des échelles micrométriques. Néanmoins, une propagation de faisceau mal maîtrisée, associée à des mécanismes d'interaction complexes fonction de la cible irradiée, peuvent impliquer de fortes disparités sur la qualité d'usinage. Dans le cadre d'une application industrielle donnée, ces travaux nous ont donc permis d'approfondir les principales étapes d'optimisation d'un tel procédé selon des critères de reproductibilité, de qualité et de rapidité. Pour cela, nous avons tout d'abord souligné l'influence des propriétés gaussiennes des faisceaux et de leur perturbation afin de définir la distribution énergétique au niveau des plans de focalisation. Aussi, la quantification de l'interaction via les critères de seuil et de taux d'ablation, d'incubation et de saturation a contribué à comprendre la réaction du matériau de manière macroscopique. Les problèmes méthodologiques inhérents à leurs calculs ont été mis en évidence et ont permis par la suite d'anticiper les formes d'usinage ainsi que les temps de procédé. Dans un second temps, l'optimisation des paramètres laser s'est appuyée sur des caractérisations aussi bien qualitatives pour l'aspect visuel que quantitatives avec l'estimation de la stoechiométrie et des contraintes résiduelles au niveau des flancs d'usinage. Nous avons en outre tiré profit de la piézoélectricité afin de développer une méthode d'observation in situ de la réponse à l'onde de choc laser contribuant à la compréhension des fissurations apparentes. Nous proposons au terme de ce travail un jeu de paramètres optimal pour la découpe de PZT assurant une bonne répétabilité du procédé tout en minimisant les défauts d'usinage comme la fissuration, les dépôts de surface et les irrégularités de bords. Des essais sur la mise en forme spatio-temporelle de faisceau sont enfin abordés principalement en tant que perspective d'accélération du procédé et encouragent son utilisation pour une future industrialisation
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39

Yang, Li-Ting, and 楊立婷. "Analysis of Cutting Force and AE Signals for Cutting Performance in Mechanical Cutting of Ceramics." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/jx8dg6.

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碩士
國立中興大學
機械工程學系所
106
With the continuous development of new technology to improve the product quality, brittle materials such as single crystal silicon, glass, ceramics, and sapphire draw much more attentions lately for component design. However, lack of efficiency in the manufacturing of ceramics limits its application. Therefore, the development of new manufacturing method with machining efficiency higher than grinding will play a very important role to reduce the cost and extend its applications. In this study, experiments are design to analyze the machinability of Zirconium Oxide, Aluminum Oxide, and Silicon Carbide, and the relationship between the chip formation mode and acoustic emission (AE) signal generated from the machining process. To simulate the orthogonal cutting for the fundamental analysis of chip formation of three materials, planning process was conducted on a research platform with the same cutting speed and various depth of cut. During the process, the cutting force, vibration, and the AE signals were collected simultaneously to study the relationship between cutting mode and signals. A high speed camera is also installed to monitor the cutting condition. After the machining, the chip was collected to confirm the chip form by SEM and the surface condition was investigated by white light interferometer. The results show that different machinability for three materials can be observed. The ductile mode and the transition to the brittle mode machining can be observed for the machining of Zirconium Oxide and Silicon Carbide in this study, but only brittle chip can be observed in the machining of Aluminum Oxide. Considering the critical depth of cut for both materials with ductile mode machining, Zirconium Oxide demonstrates the higher value than Silicon Carbide. In the study of the relationship between the acoustic emission signal and cutting mode, the distribution change can be observed when the cutting mode changes from ductile mode to brittle mode. The higher value of the high frequency to low frequency energy ratio can be observed for both Zirconium Oxide and Silicon Carbide in the brittle mode machining than in the ductile mode machining. Based on the pattern change of the AE frequency domain signal, the capability of applying the AE signal for the cutting mode monitoring can be confirmed.
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40

Lin, Lin, and 林琳. "Study on the Development of Ceramics Cutting and Pasting and Koji Pottery in Taiwan." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/e2wjzw.

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碩士
國立雲林科技大學
建築與室內設計系
107
The importance of the traditional culture and architecture of the Koji Pottery and Ceramics Cutting and Pasting., in addition to its beautification function, also responded to the Lord's dedication to the god, and conveyed the meaning through the works. Its development inherited the culture of the South China and fell deep into the land. The material has evolved so far. Genre. In the inheritance system of Taiwanese opera ware, pottery and shear, the creation craftsmen Ye,Lin-Zhi and He,Jin-Long are important systems in Taiwan. Their influence on the follow-up craftsmanship and inheritance are examples of future generations of craftsmen. In this study, first the literary Xi Wen Tao was misnamed Jiao Zuo Tao as a correction, and then the art form of the Koji Pottery and Ceramics Cutting and Pasting, the craftsman inheritance system, the construction method, the composition method and the form principle, etc., were combined by the field survey and interview data. Analyze and discuss the influence of the art of Koji Pottery and Ceramics Cutting and Pasting on Taiwan, and try to understand the characteristics of its craftsmanship and the division of teachers. Hopefully, it will make positive and positive contributions to the study of Taiwanese craftsmen. After the use of traditional aesthetics to analyze the composition of the theme of the craftsman's thinking, through this research and analysis of the development of traditional craftsmanship, do a little effort.
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41

Oliveira, José João Pacheco de. "Valorização de Lamas Graníticas de Corte e Polimento." Master's thesis, 2015. http://hdl.handle.net/10316/38762.

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Dissertação de Mestrado Integrado em Engenharia do Ambiente apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
O Granito é um material geológico de elevado interesse comercial. Rocha magmática constituída por quartzo, feldspato e micas, é amplamente utilizada na construção civil e enquanto rocha ornamental. O setor da transformação de rocha ornamental granítica gera um grande volume de lamas nas suas operações de corte e polimento, passivas de serem sujeitas a uma operação de R5 (Reciclagem/recuperação de outros materiais inorgânicos) ou seja transformação dos resíduos de modo a servirem um fim útil, substituindo outros materiais que, caso contrário, teriam sido utilizados para um fim específico, neste caso em particular na produção de artigos cerâmicos. A caraterização física e química das lamas graníticas de corte e polimento assume um papel crucial para a validação da valorização destes materiais em revestimentos cerâmicos e em cerâmicas técnicas, atendendo às especificidades produção e normativas de cada uma destas situações.
Granite is a geological material of high commercial interest. This magmatic rock composed of quartz, feldspar and mica, is widely used in construction and as ornamental stone. The sector of granite transformation into an ornamental stone generates a large volume of sludge in its cutting and polishing operations, that can be submitted to a R5 operation (Recycling / recovery of other inorganic materials) in which the waste would serve a useful purpose by replacing other materials which would otherwise have been used for a specific purpose, in this particular case to product ceramics. Physical and chemical characterization of sludge granite cutting and polishing takes on a crucial role in the validation of the incorporation of these materials in ceramic tiles and technical ceramics, considering the production and regulations specificities for each of these situations
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42

LI, ZHAN-WEI, and 李展維. "Reliability analysis of ceramic cutting tools." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/91438451423284788573.

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43

Wengsh, Su, and 蘇文石. "Carbon Dioxide Laser Cutting and Drilling Alumina Ceramic." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/43012365742662600585.

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44

Chen, Hong-Wen, and 陳鴻文. "Laser fracture milling and cutting techniques for thick ceramic substrate." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/03165303817848860415.

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碩士
華梵大學
機電工程研究所
89
A new laser machining technique for ceramic material based on the concept of fracture machining is proposed in this paper. The material removal is due to the crack propagation and the linkage of defects. The original concept of fracture machining comes from the laser cutting technique with controlled fracture for the brittle thin plate. The conventional laser machining requires high laser power and will result in many cracks during the grooving process. But the required laser power of the required laser power of the present method is much smaller than the traditional method. The finite element software ANSYS is used to analyze the temperature and stress distribution during the laser machining process. The experimental specimens are Al2O3 ceramic, and the laser sources are CO2 laser and Nd：YAG laser. The technique of edge machining for ceramic thick plate is investigated. The relationships of process parameters such as material removal rate, surface roughness, laser scanned speed, laser power, and feed speed of laser is also discussed. The fundamental models of material removal of strip material and fracture machining element are proposed. They can be applied on the edge milling and center blind-cavity milling for arbitrary shape. Finally, the two penetrated cutting methods for thick ceramic substrate are discussed. One is applying the CW focused Nd-YAG laser and the defocused CO2 laser at the same time to separate the ceramic substrate, in which the cutting depth can reach 10mm. The other is using Nd-YAG laser to scribe a groove-crack on a substrate, then applying the defocused CO2 laser at the back-side of the substrate to separate the material. Using this way to proceed more complicated curve cutting, the result of ceramic substrates are better than traditional method, not only on the rough status, but the crack faults, and so on, furthermore it decreases substantially the demands of laser power.
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45

CHANG, PO-LIANG, and 陳柏良. "Optimization cutting distance by using ceramic tool for fine cutting−A case study of heat treated S50C." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/zh4532.

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碩士
國立臺北科技大學
精密機構設計產業研發碩士專班
103
The present study explores conducting wet turning finishing operations on S50C steel with hardness of HRC52 after heat treatment, using ceramic tools with alumina and titanium carbide base. Feed, spindle speed, and cutting depth are used with the nine experimental parameters of the Taguchi method orthogonal arrays, conforming to the surface roughness requirements to obtain the longest cutting distance of fine turning. After analysis of the experimental data obtained, we found that the most influencing factor of cutting distance is feeding and spindle speed and that cutting depth has the minimal impact. Under the optimum turning condition of spindle speed of 550 rpm, feed 0.02 mm/rev, and axial cutting depth 0.15 mm, compared with the original turning conditions of company S, i.e., 1336.5 mm, the value reached 1485 mm after improvement, and the cutting distance increased by approximately 10%. Thus, the upper limit of the finishing distance increased from the original 668.3 to 742.5 mm. Based on the tool life empirical formula derived in this study through experimental data, after optimizing the turning conditions forecast using the Taguchi method and comparing the experimental data obtained after confirmation, the experimental data error predicted by the Taguchi method was 3.7%. Furthermore, the real data error of tool life calculated by ceramic tools empirical formula was 11.1%.
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46

Chu, Yung-Che, and 朱永哲. "On-line Ceramic Cutting Tool Flank Wear Monitoring in Hard Turning." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/07965302084370274954.

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碩士
國立中興大學
機械工程學系所
102
Hard turning is that turning the harden steels as final processes or fine machining to replace grinding processes. In the cutting process, tool wear cause surface roughness and dimensional precision getting worse. Ceramic tool with high hardness, high strength, wear resistance, chemical stability and cheaper price, but it’s sensitive to processing condition. It’s important that monitoring the tool wear of ceramic tool in hard turning. This research studies the ceramic tool flank wear on-line monitioing in hard turning. The ceramic insert A65 used in hard turning experiment to turn the die steel SKD61 which harden to HRC60 by heat treatment. The acoustic emission sensor and the dynamometer using to obtain the acoustic emission signal and cutting force on sharp tool, VB 0.05mm, VB 0.1mm and VB 0.15mm of ceramic tool in hard turning. Then analyze and studies the relationship between the flank wear of ceramic tool, cutting force and acoustic emission. The result of experiment that the cutting force in x-axis, y-axis and z-axis will increase when the flank wear of ceramic tool increase. On the other hand, the acoustic emission energy decrease when the flank wear of ceramic tool from sharp tool increase to VB 0.1mm. Then the acoustic emission energy sharply increase when the flank wear from VB 0.1mm to VB 0.15mm. Using FFT to transform the acoustic emission signal from time domain to frequency domain. In frequency domain, the trend of most of frequency are the same as time domain of acoustic emission signal. However, in some particular frequency range (nearby 170 kHz or 185 kHz), the acoustic emission energy increase when the flank wear increase from sharp tool to VB 0.15mm.
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47

Huang, Hsin-Hsien, and 黃信賢. "A Study on the Optimum Parameters in Laser Cutting Ceramic Substrate." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/31031872148170104287.

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碩士
國立屏東科技大學
機械工程系所
95
The purpose of this study is to investigate the characteristics of the cutted surface roughness, cutted taper and dross height of workpiece in laser cutting Al2O3 ceramic substrate by Nd:YAG laser, such that the multiple quality objectives for optimized model has been constructed. This research procedure can be divided into experimental work, analysis for single and multiple quality objectives. Firstly, the orthogonal array of Taguchi method is used to arrange experimental work. The laser cutting parameters include impulse repeatability, peak power, impulse width, impulse frequency, focusing point, cutting speed, the thickness of ceramic substrate and gas pressure. The cutting qualities of the cutted surface roughness, cutted taper and dross height of workpiece are measured, and then three sets of optimum laser cutting parameters for the single objective of cutting qualities can be found by using Taguchi method, separately. Furthermore, combining these three cutting qualities as multiple objectives to find the optimum laser cutting parameters can be conducted by incorporating grey relational analysis or Mahalanobis-Taguchi system. It showed that the best results for cutted surface roughness is 3.075μm, for cutted taper is 2.976˚ and for dross height of workpiece is 0.33335mm in the single objective analysis by using Taguchi method, separately. While the cutted surface roughness of 3.722μm, cutted taper of 3.646˚ and dross height of workpiece of 0.37601mm has been obtained in the multiple objective by using Taguchi method combining grey relational analysis, and the cutted surface roughness of 3.302μm, cutted taper of 3.984˚and dross height of workpiece of 0.44968mm has been found in the multiple objective by using Mahalanobis-Taguchi system. However, grey relational analysis improves 68% and Mahalanobis-Taguchi system improves 56.52% in entire quality characteristics by comparing with the experimental result of the second set arranged by orthogonal array. The best experimental result and standard deviation are in respective objective of Taguchi method to all optimum models, the experimental result and standard deviation in grey relational analysis and Mahalanobis-Taguchi system are inferior to all optimum models, and the worst experimental result and standard deviation are in nonrespective objective of Taguchi method to all optimum models. It can be concluded that Taguchi method is better selection to single objective, and then grey relational analysis or Mahalanobis-Taguchi system are better selections to multiple objectives. Obviously, these types of optimized models are good enough for the relational research in laser cutting and can be used for practical applications in related industry.
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48

CHANG, KAI-SHIANG, and 張凱翔. "Treatment of High Concentration Cutting Oil Wastewater by using Ceramic Membrane Bioreactor." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/tv6533.

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碩士
國立臺北科技大學
環境工程與管理研究所
105
In global manufacturing industries, almost all cutting equipment uses cutting oil. During this process, oily wastewater is directly produced and it is difficult to treat. In this study, the treatment of cutting oil has been discussed. The chemical coagulation method was used as pretreatment process due to the issue of loading the high concentration cutting oil wastewater in biological tank. The pH was controlled by using H2SO4, during coagulation pretreatment. The removal efficiency of coagulant at different dosages and pH was investigated to obtain COD removal efficiency and oil content. During the coagulation test, Aluminum sulfate with the polymeric coagulant was utilized in SB721 wastewater which is used in the production of cutting oil SB721. The final results revealed that the COD removal efficiency was found to be 96% when the coagulation test has been performed with Al3+ dosage of 800 mg/l and at pH 6. Industrial wastewater shows better coagulation effect while utilizing commercial coagulants. In this study, the ceramic membrane was used and combined with MBR system to treat the cutting fluid wastewater. Furthermore, different kind of chemical coagulants have been utilized for pretreatment purpose to obtain the supernatant and eventually this wastewater (supernatant) was treated by MBR process. Additionally, ceramic membrane offers three advantages such as high mechanical strength, drug resistance and high reusability. During the experiment, the backwash technique was used for every interval of 10 minutes to minimize the membrane fouling. In the MBR process, HRT was used as an indicator to assess COD and oil removal efficiency. The backwash method was applied to reduce the membrane fouling and further, the filtration pressure as well as water flux was thoroughly analyzed to examine the requirement of chemical washing of the membrane. The results showed that the COD removal efficiency was evaluated to be 97.5, 97.6 and 98.5% when the HRT was 9, 18 and 36 hours in SB721 wastewater. Finally, the oil removal efficiency was analyzed to be > 99%, which is equivalent to 1 mg/L oil concentration. In the industrial wastewater, the effluent from the pretreatment was found to be 994-1156 mg / L. During the MBR process, the removal rate was evaluated to be 93% of 7.5 hours HRT.
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49

Shiu, Jian-Shiun, and 徐建勳. "Laser Cutting by using the Stable and Unstable Fracture Techniques for Ceramic Substrates." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/77762671979450029982.

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碩士
華梵大學
機電工程研究所
92
Two new laser cutting techniques of pre-scribing controlled fracture method and unstable fracture method were proposed in this paper. The feasibility of laser cutting with closed cutting path was also discussed. It was found that the unstable failure will occur in cutting a closed straight-line or a closed circle. In the pre-scribing controlled fracture method, a diamond wheel is used to scribe a micro-groove along the cutting path in an alumina substrate. The substrate is then separated by applying a defocused laser beam throughout the scribed line for driving the micro-crack through the substrate thickness. The cutting speed of the pre-scribed substrate is larger than that of the un-scribed substrate by four times. The alternative laser cutting technique with unstable fracture method was developed successfully. Applying a defocused laser along the scribed line within a short length about ten millimeters, a great thermal stress will be induced at the scribed groove and make the substrate breaking unstably along the scribed line. The breaking speed is very high and the quality of breaking surface is very good. But the cutting will fail, if cutting geometry is asymmetrical. The finite element software ANSYS was used to analyze the temperature field and stress field. The SEM photographs of the breaking surface and the acoustic emission data were obtained to analyze the micro-mechanism of the laser cutting process. Finally, the relationships between laser power, scribing depth, and specimen size were also investigated.
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50

Yang, Yung-Chi, and 楊永吉. "Effect of ceramic turning tool with different coating material on the cutting performance." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/71269266974519926584.

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碩士
桃園創新技術學院
機械工程系機械與機電工程碩士班
103
This study using aluminum oxide powder added with a small quantity of element, then sintering at high-temperature to obtained ceramic cutter, which has higher hardness, heat resistance, and his turning speed can higher than tungsten carbide cutter. This ceramic cutter coating with TiN and TiAlN, then utilize the ECOCA SL-8 CNC lathe with the feeding rate of 0.1mm/rev and feed quantity of 1, 1.5, 2, and 2.5mm under the condition of cutting rotational speed 1,000 rpm and fixed turning speed 78.5 m/min, to turning S45C round rod with volume 31416 mm3. Then measure the surface roughness using T500 surface roughness tester to explore the effect of cutter on cutting performance. From the experimental results, it was found that ceramic cutter coating with TiN and TiAlN, can increased cutting life 22.7% and 68.2% , respectively, under the cutting rotational speed 1,000 rpm. Alternatively, it can increased cutting life 32.3% and 47.7%, respectively, under the fixed turning speed 78.5m/min. But ceramic cutter coating with TiAlN will increase significantly the surface roughness of cutting workpiece. It was also found that the cutter life under the fixed turning speed is longer than the cutting rotational speed regardless of coating. Meanwhile, the cutter life will decreases with increasing the feed quantity. The surface roughness of cutting workpiece will decreases with increasing the feed quantity.
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