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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Implementação e análise de um retrofitting aplicado em uma máquina de 3 eixos

Peixôto, Wagner Correia 26 February 2016 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-05-22T13:42:24Z No. of bitstreams: 1 arquivo total.pdf: 4721146 bytes, checksum: 62290d20efdd12371f2308dd6752ec65 (MD5) / Made available in DSpace on 2017-05-22T13:42:24Z (GMT). No. of bitstreams: 1 arquivo total.pdf: 4721146 bytes, checksum: 62290d20efdd12371f2308dd6752ec65 (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The computer numerical control machine tools, or CNC machine tools, emerged due to the need of the aviation industry to produce increasingly complex and accurate parts. The retrofitting of machine tools is the modification of a traditional machine for a computer numerical control one. Due to the popularization of computers, electronic components decreased costs, Internet expansion and open source projects, the retrofitting has become increasingly widespread in industry as an option for the purchase of new machine tools with CNC included. The objective of this study was to implement the retrofit on a 3-axis machine from the Precision Engineering Laboratory of the Federal University of Paraíba. For this adaptation, the machine has been modified to use a kit with interface drivers from HobbyCNC and new stepper motors. After the retrofit, it used a 80-XL Laser system for measuring position errors. The tests were performed on each axis, commanding the machine to five positions and measuring the actual positions reached and, then, the same tests were carried out in reverse direction. With the measured results, the positioning errors, hysteresis, repeatability and accuracy calculated by ISO 230-2 standard. It was conducted other tests in compensating the previously measured errors on the Y axis. There was a significant improvement on the Y-axis accuracy after compensation. Also, angular errors tests were carried out, with the use of an electronic level Talyvel 5, along the axis Y. The results of the test were satisfactory and the retrofitting reached its expectations, providing the possibility of further research in the area of numerical control. / As máquinas-ferramentas com controle numérico computadorizado, ou máquinasferramentas CNC, surgiram devido à necessidade da indústria da aviação para produzir peças cada vez mais complexas e precisas. O retrofitting de máquina-ferramenta é a modificação de uma máquina tradicional para uma com controle numérico computadorizado. Devido à popularização dos computadores, diminuição de custos dos componentes eletrônicos, expansão da Internet e projetos de código aberto, o retrofitting tornou-se uma opção cada vez mais comum na indústria como alternativa para a compra de novas máquinas-ferramentas com CNC incluso. O objetivo deste estudo foi a implementação do retrofitting em uma máquina de 3 (três) eixos no Laboratório de Engenharia de Precisão da Universidade Federal da Paraíba. Para essa adaptação, a máquina foi modificada para utilizar um Kit com drivers de interface da HobbyCNC e novos motores de passo. Após o retrofitting, foi utilizado um sistema Laser XL-80 para medição dos erros de posicionamento. Os testes foram realizados, em cada eixo, comandando-se a máquina para 5 posições e medindo-se as posições reais atingidas e, depois, foram realizados os mesmos testes no sentido inverso. Com os resultados medidos, são calculados os erros de posicionamento, histerese, repetitividade e exatidão conforme a norma ISO 230-2. No eixo Y foi realizado outros testes com a compensação dos erros medidos anteriormente. Houve uma melhora significativa na exatidão do eixo Y após a compensação. Também foram realizados testes de erros angulares, com a utilização de um nível eletrônico Talyvel 5, ao longo do eixo Y. Os resultados obtidos no teste foram satisfatórios e o retrofitting atingiu suas expectativas, por proporcionar a possibilidade de realizar mais pesquisas, na área de Comando Numérico Computadorizado.
152

Marketing Programmes And Technological Developments Across Product Life Cycle : An Exploratory Study In Indian Machine Building Sector

Mohan, Avvari V 09 1900 (has links) (PDF)
No description available.
153

Finanční analýza podniku M-MOOS, s.r.o. / Financial analysis of company M-MOOS, s.r.o.

Mirtes, Filip January 2008 (has links)
The aim of this dissertation was to carry out a financial analysis of M-MOOS, s.r.o.. This company mainly conducts general overhauls of machine tools. The dissertation is divided into five main parts. The first, theoretical part, depicts the various methods and indicators used in financial analysis. The next three parts describe the history of M-MOOS, s.r.o., it's line of business and microenvironment. The last, practical part, conducts a financial analysis of the company by using the various methods and tools already described. Furthermore, it suggests possible ways that could solve ascertained deficiencies.
154

Planejamento de trajetórias e implementação de técnicas de posicionamento de eixos para dispositivo CNC com arquitetura de controle aberta / Trajectory planning and implementation of axes positioning techniques for CNC device with open control architecture

Santos, Luciano Antonio Frezzatto, 1986- 18 August 2018 (has links)
Orientador: João Maurício Rosário / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T19:32:48Z (GMT). No. of bitstreams: 1 Santos_LucianoAntonioFrezzatto_M.pdf: 5750912 bytes, checksum: c4a22f3fc8b9c19bf5c3cac9557903c4 (MD5) Previous issue date: 2011 / Resumo: Máquinas-ferramenta CNC são dispositivos complexos que executam movimentos automáticos, precisos e consistentes. Com o propósito de aprimorar o desempenho destes dispositivos face às mudanças bruscas de parâmetros agregados a posição, velocidade e aceleração no decurso de determinada trajetória torna-se imprescindível o estudo de novas arquiteturas de controle. A automação flexível permite que dispositivos robóticos mostrem-se cada vez mais velozes, motivando o desenvolvimento de técnicas que possibilitem de modo eficiente a substituição de controladores clássicos do tipo PID. Este estudo propôs-se a implementar um método alternativo para acionamento de um dispositivo cartesiano CNC de alta precisão com ênfase no desenvolvimento de um ambiente computacional para planejamento de movimentos e síntese de controladores. A geração de movimentos foi realizada por meio de um método de interpolação por splines que garantiu a continuidade e a suavidade dos perfis de trajetória. Para garantir que tais perfis fossem corretamente executados pelo dispositivo cartesiano, dois métodos de controle baseados no modelo do sistema foram implementados de forma a estabelecer comparação entre seus desempenhos. Em seguida, concebeu-se um ambiente de simulação com arquitetura aberta e flexível, o qual permitiu validar as estratégias propostas além de analisar a influência que perturbações externas causavam sobre o comportamento do dispositivo cartesiano. Tendo as estratégias sido validadas, procedeu-se à implementação em dispositivo físico utilizando uma placa FPGA para embarcar os controladores sintetizados. Os resultados mostraram que as estratégias propostas apresentaram bom desempenho quando empregadas junto ao dispositivo cartesiano CNC. Outrossim, o ferramental desenvolvido no estudo é suficientemente genérico para ser estendido a outras aplicações utilizando máquinas-ferramenta CNC / Abstract: CNC machine tools are complex devices that execute automatic, precise and consistent movements. Aiming to improve the performance of these devices due to sudden changes on parameters associated to position, speed and acceleration while performing a given trajectory, it becomes indispensable the study of new control architectures. The flexible automation allows faster robotic devices, motivating the development of techniques that efficiently substitute classic PID controllers. This study aimed to implement an alternative method for driving a high-precision CNC cartesian device focusing on the development of a computing environment for movement planning and synthesis of controllers. The movement generation was performed by means of a spline interpolation method that ensured the continuity and smoothness of trajectory profiles. To ensure that these profiles were correctly executed by the cartesian device, two control techniques based on the model of the system were implemented in order to establish comparisons between their performances. Then, a simulation environment with open and flexible architecture was conceived, which allowed the validation of the proposed techniques besides analyzing the influence of external disturbances on the cartesian device behavior. Having the strategies been validated, the implementation in physical device was done using a FPGA board to embed the synthesized controllers. The results showed that the proposed strategies had good performance when applied to the CNC cartesian device. Furthermore, the tools developed in the study are general enough to be extended to other applications using CNC machine tools / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica
155

Do projeto à fabricação : um estudo de aplicação da fabricação digital no processo de produção arquitetônica / From design to manufacturing : a study of the use of digital fabrication in the architectural production process

Barbosa Neto, Wilson, 1983- 24 August 2018 (has links)
Orientador: Maria Gabriela Caffarena Celani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-24T11:31:11Z (GMT). No. of bitstreams: 1 BarbosaNeto_Wilson_M.pdf: 18612146 bytes, checksum: d8fbaaa3aaa7ff8e9008c22519dc03e7 (MD5) Previous issue date: 2013 / Resumo: A utilização de técnicas de Fabricação Digital está cada vez mais presente no campo da arquitetura e construção por todo o mundo, devido aos avanços tecnológicos que os sistemas CAD (Computer-aided Design) e CAM (Computer-aided Manufacturing) têm proporcionado aos processos de concepção e produção da obra arquitetônica. As possibilidades que essas ferramentas oferecem aos arquitetos e projetistas abrem caminho para novas abordagens de projeto, que permitem o uso da produção automatizada sem a necessidade de uma padronização tão rígida como aquela imposta pelo sistema industrial. Entretanto, nota-se que a aplicação dos métodos de Fabricação Digital no processo de produção do espaço edificado no Brasil é lento, quando comparado a outros países onde a tecnologia necessária para o exercício da técnica já se encontra amplamente difundida. A presente pesquisa tem como foco investigar a aplicação da Fabricação Digital, por intermédio de processos file-to-factory na produção arquitetônica de elementos para a construção civil, mais especificamente com o uso de técnicas subtrativas de corte 2D. Após um levantamento sobre o estado da arte da área e o desenvolvimento de dois estudos de caso, o método utilizado foi a pesquisa-ação, por meio de um exercício de aplicação do conceito file-to-factory. O processo de projeto foi documentado detalhadamente e analisado para a sistematização dos procedimentos, que servirão de referência para futuras aplicações no campo da arquitetura. Espera-se, com isso, contribuir para a divulgação dessas novas tecnologias na produção arquitetônica no cenário brasileiro / Abstract: The use of Digital Fabrication techniques is increasingly present in the field of architecture and construction throughout the world. Systems such as CAD (Computer-aided Design) and CAM (Computer-aided Manufacturing) have provided technological advances to the architectural design and production process. The possibilities that these tools provide to architects and designers introduce new design approaches, which allow the use of automated production without the rigid standardization imposed by the industrial system. However, it can be noticed that the use of Digital Fabrication methods in the built environment production process in Brazil is slow when compared to other countries where the technology is widely incorporated. This research focuses on investigating the application of Digital Fabrication, through file-to-factory processes in the production of architectural elements for the construction industry, specifically with the use of 2D subtractive cutting techniques. After a survey on the state of the art in the field and two case studies, the method used was an action research through a file-to-factory exercise. The design process was documented in detail and analyzed in order to systematize the procedures as a reference for future applications in architecture. As a result we expect to contribute to the dissemination of these new technologies in architectural production in the Brazilian scenario / Mestrado / Arquitetura, Tecnologia e Cidade / Mestre em Arquitetura, Tecnologia e Cidade
156

Využití technologie virtuální reality k monitoringu a vizualizaci vybraných provozních vlastností stroje a jejich analýze / Use of Virtual Reality Technology for Monitoring and Visualization of Selected Operational Charakteristics of Machines and Their Analysis

Augste, Jan January 2017 (has links)
This dissertation deals with the study of the use of virtual technologies for an analysis of operating characteristics of a machine. Operating characteristics of a machine are parameters that determine the usability of the machine to accomplish a certain task in addition to the specified time and under the certain conditions. These include parameters that can be changed based on customer requirements, for example, the table size and the highest spindle speed to the parameters influenced from the start of the machine design such as positioning accuracy, acceleration value in the axes or consumption. The first part sets out general requirements for visualization of information and these are subsequently verified experimentally in the chapter devoted to the time visualization protocol. This thesis presents the original experiments to determine the basic requirements for visualization of a measured quantity, in this case the feed rate. By verifying usability when displaying these properties on the underlying data showing machine position change, the four basic requirements for visual data processing using immerse virtual reality are validated. A deeper insight into the work with data will enable to analyse more complicated relations within a longer period, greater transparency and clearer outputs of analysis.
157

Racionalizace technologie obrábění / Rationalization of machining technology

Plančar, Jakub January 2018 (has links)
This diploma thesis is focused on a design of rationalization solutions for machining workplace in Siemens Company. The machined pieces are shafts, the basic components of the electric motors. The introductory part of this study describes the theoretical basics of machining technology, especially milling. The next part is focused on the company presentation, the analysis of the existing workplace and its technologies and components. In the following section are selected weaker production sites, and then is presented opportunities for improvement and rationalization of this workplace. Following the elaboration of the selected rationalization solution, along with techno – economic evaluation of the production change, which highlights the results of this study.
158

Vibration Control for Chatter Suppression with Application to Boring Bars

Pratt, Jon Robert Jr. 18 December 1997 (has links)
A mechatronic system of actuators, sensors, and analog circuits is demonstrated to control the self-excited oscillations known as chatter that occur when single-point turning a rigid workpiece with a flexible tool. The nature of this manufacturing process, its complex geometry, harsh operating environment, and poorly understood physics, present considerable challenges to the control system designer. The actuators and sensors must be rugged and of exceptionally high bandwidth and the control must be robust in the presence of unmodeled dynamics. In this regard, the qualitative characterization of the chatter instability itself becomes important. Chatter vibrations are finite and recognized as limit cycles, yet modeling and control efforts have routinely focused only on the linearized problem. The question naturally arises as to whether the nonlinear stability is characterized by a jump phenomenon. If so, what does this imply for the "robustness" of linear control solutions? To answer our question, we present an advanced hardware and control system design for a boring bar application. Initially, we treat the cutting forces merely as an unknown disturbance to the structure which is essentially a cantilevered beam. We then approximate the structure as a linear single-degree-of-freedom damped oscillator in each of the two principal modal coordinates and seek a control strategy that reduces the system response to general disturbances. Modal-based control strategies originally developed for the control of large flexible space structures are employed; they use second-order compensators to enhance selectively the damping of the modes identified for control. To attack the problem of the nonlinear stability, we seek a model that captures some of the behavior observed in experiments. We design this model based on observations and intuition because theoretical expressions for the complex dynamic forces generated during cutting are lacking. We begin by assuming a regenerative chatter mechanism, as is common practice, and presume that it has a nonlinear form, which is approximated using a cubic polynomial. Experiments demonstrate that the cutting forces couple the two principal modal coordinates. To obtain the jump phenomena observed experimentally, we find it necessary to account for structural nonlinearies. Gradually, using experimental observation as a guide, we arrive at a two-degree-of-freedom chatter model for the boring process. We analyze the stability of this model using the modern methods of nonlinear dynamics. We apply the method of multiple scales to determine the local nonlinear normal form of the bifurcation from static to dynamic cutting. We then find the subsequent periodic motions by employing the method of harmonic balance. The stability of these periodic motions is analysed using Floquet theory. Working from a model that captures the essential nonlinear behavior, we develop a new post-bifurcation control strategy based on quench control. We observe that nonlinear state feedback can be used to control the amplitude of post-bifurcation limit cycles. Judicious selection of this nonlinear state feedback makes a supplementary open-loop control strategy possible. By injecting a harmonic force with a frequency incommensurate with the chatter frequency, we find that the self-excited chatter can be exchanged for a forced vibratory response, thereby reducing tool motions. / Ph. D.
159

Concept Generation Techniques  for Machine Tool Design / Konceptgenereringstekniker för maskinverktygsdesign

RAJAGANAPATHY SUNDAR, VISHAL January 2020 (has links)
Technological advancements are reaching new milestones in modern world. The demand for innovations and discoveries in each field is growing greater. This is the challenge in front of product designers. This thesis is about designing a mechanism for a machine tool. Machining tools are used from manual lathes to modern automated Computer Numerical Control machines. Turning operation is one of the basic stages in machining workpiece. Wiper inserts are used in final stage of turning for better surface finish due to their multi-point radii. But to use efficiently, positioning tool edge is necessary. Requirements are drafted based on this objective. So, developing a mechanism to perform this function is the foundation. Understanding various concept generation techniques in design field is necessary. Such techniques are described in literature section and later applied in thesis. A systematic approach is drafted for developing concepts. Then concepts are developed using these techniques. These concepts are evaluated based on weightage criteria. Then concepts are selected for detail design and prototype manufacturing. These chosen concepts are simulated to validate and to analyse mechanical properties. It is concluded that one simple concept is better than others in performance and utility. Finally, the thoughts for future work are stated. This work provides a brief idea on approaching product development. / Tekniska framsteg når nya milstolpar i den moderna världen. Efterfrågan på innovationer och upptäckter inom varje område blir större. Detta är utmaningen för produktutvecklare. Det här examensarbetet handlar om att designa en mekanism för ett verktygsmaskin. Verktygsmaskiner används i allt från manuella svarvar till moderna automatiserade numeriskt styrda verktygsmaskin. Svarvning är ett av grundstegen i bearbetningen av ett arbetsstycke. Wiperskär används i slutskedet av svarvning för bättre ytfinish (ytfinhet) tack vare flerpunktsradier. Men för att ett wiperskär ska kunna navändas efektivt är positionering av verktygskanten nödvändigt. Krav för urformas utifrån detta mål och att utveckla en mekanism för att utföra den här funktionen är därmed grundläggande. Förståelse för olika konceptgenereringstekniker inom design är nödvändig. Sådana tekniker beskrivs i litteraturavsnittet och tillämpas senare i examensarbetet. Ett systematiskt tillvägagångssätt utarbetas för att utveckla koncepten. Sedan utvecklas koncepten med dessa tekniker. Dessa koncept utvärderas utifrån viktningskriterier. Sedan väljs koncept för detaljdesign och prototyptillverkning. Dessa valda koncept simuleras för att validera och analyseras mekaniska egenskaper. Slutsatsen är att ett enkelt koncept är bättre än andra när det gäller prestanda och nytta. Slutligen formuleras förslag på framtida arbete. Detta arbete ger inblick i hur det är att närma sig produktutveckling.
160

Real-time, open controller for reconfigurable manufacturing systems

Tlale, Moretlo Celia January 2013 (has links)
Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013 / Markets for manufactured products are characterized by a fragmentation of the market (with regards to size and time), and by shorter product cycles. This is due to the occurrence of mass customization and globalization. In mass customization, the same basic products are manufactured for a broad market, but then consumers are given the liberty to choose the “finishing touches” that go with the product. The areas that manufacturers now compete for are higher quality products, low cost and timely response to market changes. Appropriate business strategies and manufacturing technologies must thus be used to implement these strategic dimensions. The paradigm of Reconfigurable Manufacturing System (RMS) has been introduced to respond to this new market oriented manufacturing environment. The design of RMS allows ease of reconfiguration as it has a modular structure in terms of software and hardware. This allows ease of reconfiguration as a strategy to adapt to changing market demands. Modularity will allow the ability to integrate/remove software/hardware modules without affecting the rest of the system. RMS can therefore be quickly reconfigured according to the production requirements of new models, it can be quickly adjusted to exact capacity requirements as the market grows and products change, and it is able to integrate new technology. In this research project, real-time, open controller is designed and developed for Reconfigurable Manufacturing Tools (RMTs). RMTs are the basic building blocks for RMS. Real time and openness of the controllers for RMT would allow firstly, for the modular design of RMTs (so that RMTs can be adapted easily for changing product demands) and secondly, prompt control of RMT for diagnosability.

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