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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.
41

Návrh výroby nosiče čepele stroje MRZ / Messerringzerspaner / Design of MRZ / Messerringzerspaner blade carrier design

Mecová, Kamila January 2019 (has links)
The aim of the thesis is focused on the proposal of a new technological procedure of the blade carrier for use in its own production. Currently, the carrier is manufactured by the German company B.Maier Zerkleinerungstechnik GmbH. The work includes several parts. The first part deals with the component itself, its function and importance, as well as its function in the assembly and the whole machine. In the next part the technological procedure of the blade carrier production is created. Fleet of machines including the necessary tools is also designed. In a separate chapter there is an economic evaluation of the proposed solution in two different variants, a subsequent evaluation and a proposal for implementation.
42

Sestavení technologie součásti "skříň bezpřevodového výtahového stroje" pro TPV sériové výroby. / Solution technology of part "box of elevator" in batch production.

Bílek, Josef January 2010 (has links)
This diploma work deals with a production technology of a casing for a gear-less elevator in a batch production. A technological analysis of the product is done, including two grades of materials for castings or weldments. The technology of machining includes a NC program. Both production variants have been assessed and the optimal production according to selected criteria is recommended.
43

Modelagem numérica e experimental dos erros térmicos de um centro de usinagem CNC 5 eixos. / Numerical and experimental modeling of thermal errors in a five-axis CNC machining center.

Santos, Marcelo Otávio dos 12 July 2018 (has links)
Esta tese teve por objetivo desenvolver um algoritmo preciso e robusto capaz de compensar os erros térmicos volumétricos de um centro de usinagem 5 eixos em diferentes condições operacionais. O comportamento térmico da máquina foi modelado usando técnicas do método dos elementos finitos (MEF) com base na teoria do calor de atrito e calor de convecção, e validadas através dos vários campos de temperatura obtidos experimentalmente usando termopares e imagens térmicas. Os principais subsistemas da máquina foram inicialmente modelados, como o conjunto de fusos de esferas, guias lineares e motofuso, o que permitiu posteriormente a validação do comportamento termoelástico da máquina completa para onze ciclos de trabalho em vazio, seis ciclos de usinagem, nove ciclos de posicionamento e dois ciclos com temperatura ambiente variando, obtendo erros máximos inferiores a 9%, ao comparar os resultados numéricos com os resultados experimentais. A validação do modelo em elementos finitos permitiu usar os resultados obtidos para treinar e validar uma rede neural artificial (RNA) para prever os erros térmicos do centro de usinagem. Os desvios entre os erros térmicos previstos pela RNA e os calculados pelo MEF foram inferiores a 5%. Baseado nos resultados obtidos pelas medições das peças de trabalho usinadas foi possível formular e implementar um modelo de compensação dos erros térmicos no CNC do centro de usinagem, que obteve uma redução dos erros entre 62% e 100% nas peças usinadas com compensação. Foi também proposto um algoritmo de previsão e compensação dos erros térmicos para o centro de usinagem, baseado em todos os ciclos e simulações realizadas, e que se comparando com os resultados experimentais mostrou-se capaz de reduzir os erros térmicos entre 50% e 95%. Após sua validação, foi possível concluir que o algoritmo desenvolvido é uma ferramenta precisa e robusta para compensar os erros térmicos da máquina para várias condições de trabalho, podendo compensá-los mesmo com esta movendo-se a diferentes velocidades, em usinagem ou mesmo operando em temperatura ambiente variável. / This thesis aims to develop an accurate and robust algorithm capable of compensating the volumetric thermal errors of a 5-axis machining center under different operating conditions. The thermal behavior of the machine was first modeled using finite element method (FEM) techniques based on theory of friction heat and convection heat, and validated with the various experimentally raised temperature fields using thermocouples and thermal imaging. The main machine subsystems were initially modeled, such as the ball screw system, linear guides and spindle, which allowed for validating of the thermoelastic behavior of the entire machine for eleven no load duty cycles, six cycles of machining, nine cycles of positioning and two cycles with varying ambient temperature, obtaining errors lower than 9%, when comparing the numerical results with the experimental results. The validation of the finite element model allowed for the use of the results obtained to train and validate an artificial neural network (ANN) for predicting the thermal errors of the machining center. The deviations between the thermal errors predicted by ANN and the FEM simulation results were less than 5%. Based on the results obtained by the measurements of the machined workpieces, it was possible to formulate and implement a model of compensation of the thermal errors in the CNC of the machining center, which obtained a reduction of errors of 62% and 100% of the machined parts with compensation. It was also proposed a thermal error prediction and compensation algorithm for the machining center, based on all cycles and simulations performed, and that, comparing with the experimental results, it was able to reduce the thermal errors between 50% and 95%. After its validation, it was possible to conclude that the developed algorithm is an accurate and robust tool to compensate the thermal errors of the machine for various duty conditions, being able to compensate the errors even when it is moving at different speeds, in machining process or even operating in variable ambient temperature.
44

Process and machine improvements and process condition monitoring for a deep-hole internal milling machine

Wilmot, Wessley January 2017 (has links)
Milling is a widely used cutting process, most commonly applied to machining external surfaces of workpieces. When machining operations are required within hard to reach areas of components, or deep within the bore of components, alternative methods of metal removal are generally employed. Typically when milling at extended reaches, difficulties may increase exponentially when trying to achieve distances several meters into a component. Essentially every topic of the milling process becomes difficult and more convoluted. Firstly to generate a stable cutting condition, and ultimately for an operator to be able to understand the cutting conditions, when all normal senses to interpret the machining stability are removed. The aim for the research is, to enable the operation of high slenderness ratio internal milling operations to become a viable technology, by detailing the measures required, to obtain a stable cutting condition. The process needs to be monitored for degradation of the tooling due to wear, and to prevent catastrophic machine damage from tool breakage or machine component failure. This research addresses the lack of knowledge available for milling with extended reaches, and the knowledge gained to overcome the real difficulties that exist for this process. Initial experiments are conducted on a prototype machine to gain experience of the internal machining operation and the many issues that it faced. Establishing requirements of the process via investigation of the tooling and necessary auxiliary equipment, it becomes possible to consider countermeasures to address the errors generated by torsional twisting of the milling arm. A system for applying a counter torque to reduce torsional deflection errors has been employed to successfully reduce the unavoidable issue over such long distances. For the process to become manageable for an industrial operator without a high level of specialist knowledge, the application of tool condition monitoring (TCM) and process condition monitoring (PCM) had to be applied. This addresses a void in available literature and research with respect to internal machining, and enables the process to become practical for an industrial environment. For this reason the research project will concentrate on the application of TCM and PCM onto the machining system. The completion of the research resulted in the process becoming satisfyingly stable, and with a resulting accuracy that satisfies the requirements of the component. Performance of the final system rivalled or achieved better results than had been experienced by the project sponsor.
45

Inovace výroby CNC obrábění diskovitých součástí / An innovation of the CNC production of the disc-shaped parts

Křupka, Marek January 2013 (has links)
The optimal choice of cutting conditions, as well cutting tool, has a significant effect on the quality of machined part and is an essential parameter to reduce the cost of production. This thesis describes CNC turning process of disc springs made of 51CrV4 material, especially using new cutting tools and the use of higher cutting speeds. A comparison of four manufacturers of cutting tools in terms of surface quality, tool path and the machined material volume will be introduced. It was experimentally verified that our proposed facility has achieved the best result.
46

Modelagem numérica e experimental dos erros térmicos de um centro de usinagem CNC 5 eixos. / Numerical and experimental modeling of thermal errors in a five-axis CNC machining center.

Marcelo Otávio dos Santos 12 July 2018 (has links)
Esta tese teve por objetivo desenvolver um algoritmo preciso e robusto capaz de compensar os erros térmicos volumétricos de um centro de usinagem 5 eixos em diferentes condições operacionais. O comportamento térmico da máquina foi modelado usando técnicas do método dos elementos finitos (MEF) com base na teoria do calor de atrito e calor de convecção, e validadas através dos vários campos de temperatura obtidos experimentalmente usando termopares e imagens térmicas. Os principais subsistemas da máquina foram inicialmente modelados, como o conjunto de fusos de esferas, guias lineares e motofuso, o que permitiu posteriormente a validação do comportamento termoelástico da máquina completa para onze ciclos de trabalho em vazio, seis ciclos de usinagem, nove ciclos de posicionamento e dois ciclos com temperatura ambiente variando, obtendo erros máximos inferiores a 9%, ao comparar os resultados numéricos com os resultados experimentais. A validação do modelo em elementos finitos permitiu usar os resultados obtidos para treinar e validar uma rede neural artificial (RNA) para prever os erros térmicos do centro de usinagem. Os desvios entre os erros térmicos previstos pela RNA e os calculados pelo MEF foram inferiores a 5%. Baseado nos resultados obtidos pelas medições das peças de trabalho usinadas foi possível formular e implementar um modelo de compensação dos erros térmicos no CNC do centro de usinagem, que obteve uma redução dos erros entre 62% e 100% nas peças usinadas com compensação. Foi também proposto um algoritmo de previsão e compensação dos erros térmicos para o centro de usinagem, baseado em todos os ciclos e simulações realizadas, e que se comparando com os resultados experimentais mostrou-se capaz de reduzir os erros térmicos entre 50% e 95%. Após sua validação, foi possível concluir que o algoritmo desenvolvido é uma ferramenta precisa e robusta para compensar os erros térmicos da máquina para várias condições de trabalho, podendo compensá-los mesmo com esta movendo-se a diferentes velocidades, em usinagem ou mesmo operando em temperatura ambiente variável. / This thesis aims to develop an accurate and robust algorithm capable of compensating the volumetric thermal errors of a 5-axis machining center under different operating conditions. The thermal behavior of the machine was first modeled using finite element method (FEM) techniques based on theory of friction heat and convection heat, and validated with the various experimentally raised temperature fields using thermocouples and thermal imaging. The main machine subsystems were initially modeled, such as the ball screw system, linear guides and spindle, which allowed for validating of the thermoelastic behavior of the entire machine for eleven no load duty cycles, six cycles of machining, nine cycles of positioning and two cycles with varying ambient temperature, obtaining errors lower than 9%, when comparing the numerical results with the experimental results. The validation of the finite element model allowed for the use of the results obtained to train and validate an artificial neural network (ANN) for predicting the thermal errors of the machining center. The deviations between the thermal errors predicted by ANN and the FEM simulation results were less than 5%. Based on the results obtained by the measurements of the machined workpieces, it was possible to formulate and implement a model of compensation of the thermal errors in the CNC of the machining center, which obtained a reduction of errors of 62% and 100% of the machined parts with compensation. It was also proposed a thermal error prediction and compensation algorithm for the machining center, based on all cycles and simulations performed, and that, comparing with the experimental results, it was able to reduce the thermal errors between 50% and 95%. After its validation, it was possible to conclude that the developed algorithm is an accurate and robust tool to compensate the thermal errors of the machine for various duty conditions, being able to compensate the errors even when it is moving at different speeds, in machining process or even operating in variable ambient temperature.
47

Optimalizace řezného procesu pro obrábění hliníkového profilu na CNC obráběcím centru / Optimalization of cutting process for machining of aluminium profile on CNC centre

Král, Ondřej January 2019 (has links)
This master‘s thesis deals with the suggestion of suitable tools for milling aluminum alloys profiles for the construction of aperture fillings and their aplication to a CNC machining center for increasing the efficiency of the cutting process. The first part of the thesis is focused on the description of the company and the workplace of production of aluminum alloys constructions. The following pages contain description of standardized products, which are used to identify the test profile that is part of the experimental verification. Next part of this thesis is characteristic of aluminum alloys and tool materials suitable for their machining. Second part of this work contains an analysis of the current state, suggestion of new cutting tools and their application to the production proces. At the end of this thesis there is the technical-economic evaluation that deals with the time and economic savings of the applied design.
48

Obrábění rotační součásti "těleso" na CNC soustruhu / Machining of rotating Body-part on CNC lathe

Dlouhý, Vít January 2020 (has links)
This master's thesis is focused on the technology fundamentals of machining for the use of the CNC lathe which was used for machining the required parts are made of stainless steel. In the introduction are mentioned the historical milestones related to machine tools. In the following chapter is analyzed machining process and related fact. A follow-up chapter contains the parameters common to a modern machine tool CNC machines. Followed by the practical part with the characteristics of the machined components. The next chapter includes a selection of CNC lathe for production. Continued by selecting the appropriate cutting tool and adjusting the machine for the given component. They were applied a total of three variants of production with the subsequent evaluation. In conclusion, it became established fact, for example, the advantages of the shape tools or the use of more spindles during the machining.
49

Racionalizace obrábění skříní převodovek / The racionalization of machining of gearboxes

Sádlo, Dominik January 2020 (has links)
Content of the thesis is the proposal of new technology using machining centres, including five controlled axis. Benefit of implementation the new nechnology is investigated at machining example, which is the gear housing of a single stage gearbox, manufactured in the company. In the first part of the thesis, the general properties of gearboxes and their housings are analyzed, as well as the procedure of the current proces of the machining representative. In practical part of the thesis is proposed necessary tool equipment and jig equipment, needed for machining of the part. After that are analyzed and filled in time studies, provided by manufacturers of machining centres. On the bases of these studies, were calculated operating times and operating costs per one piece of the housing. In the part of technical and economical evaluation is calculated the return of initial investment, including costs for byuing new machining cente and cutting tools equipment. Finaly are evaluated the overal benefits of the new technology, given the needs of the company.
50

Posouzení bezpečnosti činností obsluhy u svislého soustružnického centra BASICTURN / Safety assessment of operator activities at the BASICTURN vertical turning center

Cunda, Ondřej January 2020 (has links)
The Master's thesis deals with the safety of operator activities at the BASICTURN vertical turning center. The first part is focused on the requirements arising from the directives of the European Parliament and the Council in relevant areas and a system analysis of the issue. The second part is a risk analysis related to operator activities on the operated machine.

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