Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Paul Dudley Hartung. / M.S.

Thesis. 1977. Mech.E.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by K. Subramanian. / Mech.E.

The cutting tool industry has evolved over the last half century to the point where an increasing range and complexity of cutting tools are available for metal machining. This highlighted a need to provide an intelligent, user-friendly system of tool selection and recommendation that can also provide predictive economic performance data for engineers and end-users alike. Such an 'expert system' was developed for a local manufacturer of cutting tools in the form of a relational database to be accessed over the Internet. A number of performance predictive models were reviewed for various machining processes, however they did not encompass the wide range of variables encountered in metal machining, thus adaptation of these existing models for an expert system was reasoned to be economically prohibitive at this time. Interrogation of published expert systems from cutting tool manufacturers, showed the knowledge-engineered principle to be a common approach to transferring economic and technological information to an end-user. The key advantage being the flexibility to allow further improvements as new knowledge is gained. As such, a relational database was built upon the knowledge-engineered principle, based on skilled craft oriented knowledge to establish an expert system for selection and performance assessment of cutting tools. An investigation into tapping of austenitic stainless steels was undertaken to develop part of a larger expert system. The expert system was then interrogated in this specific area in order to challenge by experiment, the skilled craft oriented knowledge in this area. The experimental results were incorporated into the database where appropriate, providing a user-friendly working expert system for intelligent cutting tool selection, recommendation and performance data.

Metal cutting is an important process used to manufacture components with machined surfaces or holes. Due to the wide usage o f this manufacturing process, research with the aim to optimize the cutting processes is important. Improving cutting techniques even mild)s can result in major cost savings in high volume production. Better machining practices will result in products of better precision and of greater useful life . Benefits can also be had from increasing the rate of production and producing a bigger variety of .. products with the tools available. The area of metal cutting has been researched widely by people like Tourrett, Taylor, Cohen, Davis and many others to find improved techniques and methods. This project was conducted to improve cutting conditions by ensuring that the tool geometry is always optimal . The effect of tool geometry on cutting performance has been discussed in detail by many researchers, but the practical application of these theories is an area that needs further attention. For this project a device was developed to vary the tool geometry with stepper motors on command from the controller. This device was used for research into the viability of varying tool geometry during machining to obtain different cutting conditions. Stepper motors ensure high accuracy in the control of tool geometries. The ease of controlling stepper motors, also simplified the controlling program and communication devices a lot. Rotating the stepper motors results in rotation o f the tool holder around the tool tip. Tool angles are varied without affecting the other cutting parameters like the depth o f cut, metal removal rate and cutting speed. With these cutting parameters staying the same, the change in tool geometry should result in a change in the power consumed during cutting and the force required for cutting . Other measurements for cutting performance like temperature of the tool and workpiece and the acoustic print of the tool will also change. Results prove that cutting force measurement can be used effectively to measure the optimal cutting conditions . The back rake angles and side rake angles have the biggest influence of all the tool angles on metal cutting . This is demonstrated by a number of researchers [28] as discussed in section 2 . 2. This thesis proves how the on-line changing of tool geometry, ensures the optimal cutting conditions. / Thesis (Ph.D.-Mechanical Engineering)-University of Natal, 1996.

Thesis (MEng) - School of Engineering and Science, Swinburne University of Technology, 2004. / Thesis submitted for the degree of Master of Engineering by Research, School of Engineering and Science, Swinburne University of Technology, 2004. Typescript. Includes bibliographical references: p. 116-122.

Orientador: Anselmo Eduardo Diniz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-13T03:28:51Z (GMT). No. of bitstreams: 1 ArroyoOsorio_JoseManuel_D.pdf: 25100736 bytes, checksum: 163b1aa900bc2b44578e310b2fccbe2b (MD5) Previous issue date: 2009 / Resumo: A usinagem é um dos processos de fabricação fundamentais da indústria contemporânea sendo o metal duro recoberto o material mais utilizado na fabricação das ferramentas de corte. A manufatura deste tipo de ferramentas inclui o processamento da superfície do substrato, previamente à deposição do recobrimento, com o objetivo de obter uma elevada resistência de aderência na interface substrato-recobrimento. O método mais difundido com este propósito e o jateamento do substrato com micropartículas de alumina que, embora amplamente utilizado e efetivo, gera poluição, risco à saúde do operador, consome muitos recursos de tempo e mão de obra e apresenta dificuldade no controle da rugosidade. Por outro lado a texturização a laser é uma tecnologia de engenharia de superfície baseada num laser pulsado que modifica a superfície do material através de fusão, evaporação, sublimação e subsequente solidificação. Nesta tese foi explorada a efetividade da texturização a laser como método alternativo ao jateamento na preparação pré-recobrimento da superfície do substrato. Este processo não apresenta poluição, permite o processamento seletivo de áreas especificas da ferramenta e, sendo automatizável, potencialmente utiliza menos recursos de tempo e mão de obra. As ferramentas selecionadas para experimentar foram duas classes de metal duro com recobrimento composto de TiCN+Al2O3+TiN depositado pelo processo MT-CVD, e, na preparação pré-recobrimento da superfície dos substratos experimentais foi utilizado um laser CuHBr pulsado. De acordo com a dinâmica do processo laser utilizado, é possível controlar a rugosidade do substrato e produzir uma grande diversidade de topografias e estruturas de superfície através da variação da intensidade e/ou da quantidade de pulsos do laser. Também foi verificado que o processamento com laser produz sempre transformações do WC, presente no substrato do metal duro, em novas fases não estequiométricas com menor teor de C. Por tentativa e erro, foram determinados dois conjuntos de parâmetros laser que produziram a melhor resistência de aderência avaliada através de ensaios de indentação: 02 pulsos, 410 MW·cm-2 e 64 pulsos, 239 MW. cm-2. Em ensaios de corte, tipo fresamento de topo a seco de aço molde P20 com ferramentas toroidais, foi comparado o desempenho de arestas microjateadas (comerciais) contra arestas texturizadas a laser (experimentais) encontrando uma vida média igual para ambos os tipos de arestas. Na análise detalhada dos mecanismos de desgaste foram encontradas em todas as arestas evidências de difusão, attrition, abrasão, deformação, delaminação, trincas e um mecanismo secundário, chamado desgaste por microfusão do material da aresta. Não houve diferenças notáveis entre as arestas comerciais e as experimentais que fossem atribuíveis ao processo de preparação da superfície do substrato para a deposição do recobrimento / Abstract: Machining is one of the fundamental manufacturing processes of contemporary industry and coated cemented carbide is the most used cutting tool material. Manufacturing of this kind of tools includes the substrate surface processing previously to coating deposition in order to achieve high adhesion resistance in the substrate-coating interface. The most spread out method with this intention is the substrate blasting with alumina micro-particles, which, although so widely used and effective, generates pollution, operator health risks, consumes considerable time and labor resources and presents roughness control difficulty. In the other hand, laser texturing is a surface engineering technology based on a pulsed laser which modifies the material surface through melting, evaporation, sublimation and subsequent solidification. This thesis aims to explore the laser texturing effectiveness as an alternative method for substrate surface pre-coating preparation. This process does not generate pollution, allows selective tool areas for processing and, being automated, it potentially requires less time and labor resources. The tools selected for the experiments were two kinds of coated cemented carbide with a composed TiCN+Al2O3+TiN MT-CVD coating and for the experimental substrate surface pre-coating preparation, a pulsed CuHBr laser was used. With the laser process dynamics used, it is possible to control the substrate roughness and to produce a great diversity of surface topographies and structures by adjusting the intensity and/or the amount of laser pulses. Also, it was verified that the laser processing always produces WC (present in the substrate) transformations in new non- stoichiometric phases with less C content. By trial and error method, two laser parameters sets were determined which produced the best adhesion resistance as evaluated through indentation tests: 02 pulses, 410 MW·cm-2 and 64 pulses, 239 MW·cm-2. In dry face milling cutting tests of mould P20 steel with toroidal tools, it was compared the performance of micro-blasted tools (commercial) against laser textured (experimental) ones finding an equal average life for both tool types. Detailed wear mechanisms analysis showed evidences in all the cutting edges of diffusion, attrition, abrasion, deformation, delamination, cracks and a secondary mechanism, called micro-melting wear of the material of the edge. There were no remarkable wear differences between the commercial edges and the experimental ones which could be attributable to the substrate surface pre-coating preparation process / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Orientador: Anselmo Eduardo Diniz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-23T21:54:22Z (GMT). No. of bitstreams: 1 Matsumoto_Hidekasu_D.pdf: 9333077 bytes, checksum: 51f227c51103bc62610f0c64d486742b (MD5) Previous issue date: 1998 / Resumo: Neste trabalho procurou-se estudar a viabilidade de se tornear aços no estado endurecido utilizando máquinas de projeto mecânico convencional (sem mancais hidrostáticos e com um certo desgaste) comandadas numericamente, com a finalidade substituir as operações de retificação. Para tanto, usinou-se dois tipos de corpos de prova, de aço ABNT 52100 temperado e revenido com dureza média de 60 HRc (Rockwell C), com ferramentas de corte de PCBN (65% de CBN) e cerâmica mista ('Al IND. 2¿ 'O IND. 3¿ + TiC) encontradas no mercado. Monitorou-se os ensaios via corrente do motor principal e emissão acústica, com a finalidade de determinar o momento da substituição da ferramenta de corte. Após a análise dos resultados, chegou-se às seguintes conclusões: a) é possível substituir as operações de retificação por torneamento com máquina de projeto mecânico convencional, uma vez que se obteve qualidade IT5 e rugosidade menor que Ra = 0,6 'mu¿m, com vidas das ferramentas suficientemente longas para determinadas aplicações; b) os métodos de análise dos sinais de emissão acústica e corrente do motor utilizados, não se mostraram adequados para indicar o momento da troca da ferramenta; c) em geral, a ferramenta cerâmica apresentou vida média maior que a ferramenta de PCBN, porém com uma dispersão também maior / Abstract: The main goal of this work is to study the feasibility of turning hardened steels using a lathe with a conventional mechanical design (without hydrostatic bearings), aiming to replace grinding operations. For this purpose, two kinds of quenched and tempered 52100 steel workpieces were machined, with average hardness of 60 HRc, using PCBN (65% of CBN) and mixed ceramic ('Al IND 2¿¿O IND. 3¿ + TiC) tools. Both the electrical current of the main motor and the acoustic emission were monitored, aiming to automatically establish the moment to replace the tool. After the result analyses, the following conclusions were drawn: a) it is possible to replace grinding operations by turning with a conventional mechanical design lathe, since the workpiece quality obtained was within IT5 and the surface roughness was below Ra = 0.6 ' 'mu¿m, with tool life long enough for this kind of applications; b) the tool life monitoring through acoustic emission and electrical current of the main motor did not show to be suitable to establish the moment to replace the tool; c) in general, mixed ceramic tool had longer average toollife than PCBN tool, but presented larger scatter / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Cutting tools in a manufacturing system play a significant role in metal cutting process. Cutting tools arc consumable. Tool wear affects the outcomes of machining processes such as machined· surface quality and it is normally used as an indicating parameter for tool life. It is crucial to calculate and record the wear size of different cutting tools. The tool wear is classified into many different categories according to its existing location and wear patterns. Flank wear and crater wear are the two most common types of tool wear which are used to assess the tool's life. The measurements of flank and crater wear in cutting tools have been extensively studied. There are still many challenges when these research results are applied practically. Manufacturing industry demands· accurate and rapid methods for the tool wear measurement. There are two primary objectives in this research. The first is to develop a new tool wear measurement technology by using the active contour model based image processing method for the flank wear measurement. A MATLAB program is developed to verify the suggested image processing algorithm. Many cutting experiments were conducted with different tools on a CNC machine tool. The experimental results show that the developed technology is feasible and can be used to measure the tool wear area. It needs to be noted that this method. can only extract the wear area. This method is not able to estimate the depth of the crater wear. The second objective is to develop a method for crater wear measurement by use of developed stereo vision system. This system consists of a single camera with necessary lighting devices and fixtures. A MATLAB based software is developed to estimate and represent the volume of tool wear. The proposed algorithm and feasibility of the system for the crater wear (3D tool wear) is discussed. Its effectiveness is verified in this research.

Orientador: Amauri Hassui / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T09:41:04Z (GMT). No. of bitstreams: 1 Machado_MarcioAlexandreGoncalves_M.pdf: 7046476 bytes, checksum: c4116e182c526a80c0f1d8c7b1fe8d4a (MD5) Previous issue date: 2013 / Resumo: Sabe-se que atualmente a competitividade das empresas é fator de sobrevivência. Assim, a busca por redução de custo é um constante desafio. Um aspecto dentro dos processos de fabricação que atua diretamente nesse tocante é o desenvolvimento de melhores ferramentas de corte. Este trabalho trata da reafiação de ferramentas de corte denominadas bedame, que possuem custo mais elevado que as demais ferramentas. O material usinado foi o ferro fundido nodular, que possui propriedades mecânicas características e consumir menor energia em sua fusão. Nos processos de usinagem são utilizadas as mesmas ferramentas para os ferros fundidos nodulares e cinzentos, porém o primeiro é um material dúctil, diferente do segundo que é frágil. Isso implica em um comportamento diferente na usinagem, mostrando que cabe neste caso uma melhor adequação das ferramentas de corte. Após a utilização de bedames novos, estes foram reafiados em quatro modelos diferentes. Posteriormente foram testados quatro tipos de revestimento PVD. Na sequência avaliou-se também a influência da velocidade de corte, avanço e concentração do fluido de corte. O critério adotado para a determinação do fim da vida dos bedames foi à qualidade da face usinada. Os ensaios foram feitos em sequência, sendo que o passo seguinte utilizava apenas os melhores resultados do passo anterior. Os resultados indicaram que bedames com ângulo de saída positivo, revestidos com AlTiN, usinando com menores velocidades de corte e avanço e com maior concentração de óleo no fluido de corte, apresentaram vida mais longa. Por outro lado, o mesmo bedame, só que revestido com TiCN e operando nas mesmas condições, apresentou a melhor relação custo benefício dentre os bedames reafiados. Concluiu-se assim que é viável economicamente a reafiação dos bedames / Abstract: It is known nowadays that the companies' competitiveness is a survival factor. So, the search for cost reduction is a constant challenge. One aspect of the manufacturing processes that act directly in this aspect is the development of better cutting tools. This work is about cutting tools to part materials named parting tools that has higher costs than the other cutting tools. The machined material was the nodular cast iron that has specific mechanical characteristics and demands less energy in its melting. In the machining processes it is usually used the same cutting tools to machine nodular and grey cast iron, but the first is ductile different from the second that is fragile. This implies in a different machining behavior, showing that is possible in this case a better adequation of the cutting tools. After using the new parting tools, they were resharpened in four different models. After that were tried four different PVD coatings. In the sequence it was also evaluated the influence of the cutting speed, the feed and cutting fluid concentration. The criteria adopted to determine the end of the parting tool life was the quality of the machined surface. The tests were carried out in sequence in such a way that the next step used just the best results of the former step. The results indicated that parting tool with positive rake angle, coated with AlTiN, operating in lower cutting speeds and feeds and with higher cutting fluid concentration, presented longer tool life. On the other hand, the same parting tool, but coated with TiCN and operating at the same cutting conditions, presented a better cost benefit relation among the resharpened cutting tools. It can be concluded that is economically feasible the parting tools resharpening / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Este trabalho tem como objetivo analisar as vibrações no processo de torneamento interno utilizando um porta ferramentas com a relação comprimento/diâmetro alta. Ferramentas com alto comprimento em balanço são susceptíveis a ocorrência de vibrações regenerativas durante a usinagem, alterando a estabilidade dinâmica do processo e gerando um acabamento superficial indesejado. Testes realizados para a obtenção de dados foram feitos utilizando equipamentos de medição como microfone e plataforma para medição das forças. A proposta foi de analisar a influência de parâmetros de usinagem como rotação e profundidade de corte na estabilidade dinâmica do processo de torneamento interno da liga de alumínio 6351-T6. Para isso utilizou-se os dados gerados na elaboração de uma carta de estabilidade do processo. Simultaneamente efetuou-se as simulações no software Matlab utilizando um modelo pré-estabelecido e comparando com os resultados experimentais obtidos. Para a análise dos dados coletados pelo microfone utilizou-se uma placa de aquisição de sinais, um microcomputador e um software para análise, o ITA-Toolbox. Baixas velocidades de corte propiciam maiores profundidades de corte limite devido ao efeito de amortecimento. Os resultados mostraram que este fenômeno começa a ser significativo quando a relação entre a frequência de vibração e a frequência de rotação é de aproximadamente 30 e aumenta consideravelmente para uma relação de 60. Os resultados também mostraram que para profundidades de corte abaixo do raio de ponta da ferramenta tem-se cortes instáveis porém de acordo com os modelos existentes na literatura, para um valor suficientemente abaixo da profundidade de corte o processo é sempre estável. / This work aims to analyze the vibrations in the boring process using a tool holder with high overhang. Tools with high overhang are susceptible to the occurrence of regenerative vibrations during machining, altering the dynamic stability of the process and generating an undesired surface finish. Tests performed to obtain data were made using measuring equipment such as microphone and platform for measuring forces. The proposal was to analyze the influence of machining parameters such as cutting speed and depth of cut in the dynamic stability of the aluminium alloy 6351-T6 boring process. For this purpose, the data generated in the process stability chart was used. Simulations were performed in the Matlab software using a previous model and compared with the experimental results. For the analysis of the data collected were used a microphone, a signal acquisition board, a microcomputer and a software for analysis, the ITA-Toolbox .In the end, the results showed that the depth of cut and the cutting speed have great influence on the vibration and on the stability of the boring process. Low cutting speeds provide greater cut depth of cut due to the damping effect. The results showed that this phenomenon begins to be significant when the relation between the frequency of vibration and the frequency of rotation is of approximately 30 and increases considerably to a ratio of 60. The results also showed that for depths of cut below the tool nose radius has unstable cuts but according to the models in the literature, for a value sufficiently below the depth of cut the process is always stable.