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This diploma thesis deals with grinding of parts of valves. In the first part is theoretically described valve and its manufacturing. Another part focuses on the analysis of existing grinding technology. In last part of this diploma thesis is written about choosing of suitable places for rationalization, design of rationalization and technical-economic evaluation of performed rationalization.

Coolant application is critically important in grinding, preventing workpiece damage and increasing the quality of manufactured components. However, delivery of grinding fluids is difficult to achieve, due to issues unique to grinding processes such as the air layer that surrounds the wheel. Coherent jets, which maintain their shape over a significant distance, are one of the most effective methods of coolant delivery and a significant amount of research has been devoted to developing them. Results of this work, which has largely focused on contoured nozzles, have been modest. Inspired by laminar fountains and wind tunnel design, the present work focuses on the development of a coherent, laminar jet. The developed jet possesses extreme coherence, and appears to resemble a glass rod with its stability and clarity. Investigations were carried out, comparing the coherence and cooling ability of the developed system to that of a commercially available coherent nozzle. Models for the structure of the air layer and to predict the conditions necessary for a jet to penetrate the air layer were also developed. The developed jet outperformed the commercial system both in terms of coherence and manufacturing productivity. The model was validated with experimental values, and appears to provide excellent agreement to those results. This work details the background, design, and experimentation involved in creating these innovative systems. / Thesis / Master of Applied Science (MASc)

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The main goal of this thesis is to compare 5 chosen grinding wheels, that vary by the material and structure. The testing is done in the company SLB, spol. s r.o., using a grinder on the holes BDU 80, which is set to 6 different settings of the grinding cycle, defined by the letters A´, A, B, C, D and E. These settings vary by the cutting conditions and enable to compare the tested grinding wheels by 8 measured parameters of the surface quality of the grinded bearing orbits of outer rings of the SLB 84-74 bearings, that are described by the drawing documentation.

QC 351 A7 no. 03 / The problems connected with the utilization of large high -resolution telescopes are concentrated into two principal areas. The first concerns the physical properties of the mirror disc; the second involves the pro- cessing of the mirror in the optical shop. This technical report concerns, 1) the design of a new type of opti- cal polisher, one with a stationary mirror platform, and, 2) the casting of large discs made up of a new type of glass. This new glass, designated type RZ by Owens -Illinois, has a zero coefficient of thermal expansion at 25° Centigrade. A proposal for research in these two areas has already been made. This research has been supported, in part, under Contract ONR -2173- (12) by the Advanced Research Projects Agency and administered by the Office of Naval Research.

Optimisation of the control of an autogenous grinding circuit requires a better understanding of system dynamics than exists at present. To this end extensive operating data were acquired on an industrial semi-autogenous milling circuit and a model was developed to explain the circuit responses to changes in input variables. This model represents the trends in the data fairly accurately and showed that: • When an excess o f slurry was present in Me load (i.e. more than the volume of the voids) a pool of slurry forms st the toe of the load. • The complexity of the power dependence on the variables describing the mill load defied dynamic modelling with toe limited knowledge avail- • The key parameters determining grinding efficiency vary constantly as the grinding environment is disturbed indicating a need for adaptive con- • The flow through the mili is adequately modelled by a single well mixed Itwasalso clear that maximisation of the power with respect to themass alone was insufficient, and that control of the feed dilution water rate is essential. Mill discharge slurry theology was studied eo gain an insight into conditions in the load. An energy balance using temperature measurements around th t mill discharge sump provided a very reliable estimate of the mill discharge density. This estimate was not successfully used for control although this potential should be exploited. Attempts to commission an on-line measurement of discharge slurry viscosity failed. Several theories and ideas were tested in a production environment subject to a multiplicity of disturbances and conclusive qualitative results were obtained. An improved understanding of milling circuit dynamics and a rationalisation of where controi can be improved has resulted from this work.

The cutting links on chainsaws needs to be sharpened regularly to retain its sharpness. The most effective way is to use a machine wheel grinder. However, due to high friction there is a high risk of tempering the steel and damaging the sustainability to wear, resulting in a dull cutting edge. In order to develop a grinding method that produces a good result every time, a series of parameters were tested in order to determine which combination of these generated the best grinding results. With all parameters established the results shows that the attributes of each grinding wheel are the main parameter controlling the grinding result. This project investigates the attributes of different grinding wheels and their impact on grinding results. By comparing the energy each grinding wheel uses to perform the same amount of work, each grinding wheels suitability is rated based on its performance.   The calculations and the results from the analyses and tests show which of the grinding wheels performed the work with the lowest amount of increased energy.

O método de Bond para dimensionamento de moinho de bolas tem sido utilizado nos últimos 60 anos. Baseado no ensaio de WI este método é aplicável principalmente em circuitos tradicionais, os quais incluem estágios de britagem seguidos por moagem em moinhos de barras e bolas. Apesar da grande aplicação, este método apresenta algumas limitações. Por outro lado, a simulação é uma técnica reconhecida e aplicada para modelagem e simulação de circuitos de cominuição e classificação. Embora ambos os métodos sejam complementares, não há uma integração efetiva entre ambos. Este trabalho apresenta uma técnica que permite através da modelagem e simulação estimar e melhorar o desempenho de moagem em moinhos de bolas. O trabalho tem por base amostragem em circuitos industriais de moagem, bem como o desenvolvimento de ensaios de moagem em laboratório. O desenvolvimento do trabalho será validado através da avaliação dos resultados obtidos em relação ao ambiente industrial de moagem. / The Bond method for ball mil designing has been used for 60 years. Based on Work Index test such method is applied mostly in traditional circuit configuration, which includes multi-staged crushing, followed by rod and ball milling. On the other hand simulation is a well spread and used technique for comminution and classification modeling and simulation. Even though both methods are complementary there is no effective integration between them. This work shows a technique designed to integrate both energy and modeling approaches for ball mill designing. The work is based on industrial data survey results, as well as on laboratory testing, the latter developed specifically for such a purpose. The technique will be validated under an industrial environment for assessing the obtained results.

Orientador: Eduardo Carlos Bianchi / Banca: Gilberto de Magalhães Bento Gonçalves / Banca: Luciana Montanari / Resumo: Uma técnica utilizada para substituir o método de lubri-refrigeração convencional é a mínima quantidade de lubrificante (MQL). Este método utiliza de uma mistura de óleo e ar à elevada pressão, reduzindo a quantidade de fluído de corte necessário para a usinagem. Entretanto, em diversos estudos feitos na área de retificação com MQL, nota-se que há a necessidade de aperfeiçoamento dessa técnica com relação à limpeza da zona de corte do rebolo. Devido à dificuldade do baixo fluxo de fluído, em remover os resíduos superficiais acumulados, cavados aderem à superfície da ferramenta abrasiva, preenchendo os poros do rebolo e prejudicando o processo. Sendo assim este trabalho busca promover uma técnica de limpeza para o rebolo do tipo CBN, na retificação cilíndrica de aço ABNT4340 temperado e revenido, com a utilização de MQL. Através de um dispositivo, foi colocado em contato na superfície periférica do rebolo, bastões retangulares compostos dos materiais: Teflon, Óxido de alumínio e Carbeto de silício. As variáveis de saída do processo analisadas foram o comportamento da força tangencial de corte, rugosidade, emissão acústica, relação G (volume de material removido/volume do rebolo desgastado), fotos em microscópio eletrônico de varredura, microdureza e circularidade. O método MQL com o dispositivo, foi comparado com as seguintes condições de lubri-refrigeração: Convencional; MQL sem limpeza com local de ar. Com base nos resultados obtidos, o método de limpeza utilizando o dispositivo juntamente com o bastão de carbeto de silicone, comprovou em algumas condições a obtenção de melhores resultados e ausência de danos térmicos, se comparado aos outros métodos / Abstract: A technique used to replace the method of conventional lubrification and cooling is the minimum quantity lubricant (MQL). This method uses a mixture of oil and air to the high pressure, reducing the amount of fluid required for machining. However, in various studies in the field of grinding with MQL, it is noted that there is a need for improvement of this techique with respect to cleaning the cutting zone of the wheel. Due to the difficulty of low fluid flow, to remove the accumulated surface residue, chips adhere to the surface of the abrasive tool, filling the pores of the wheel and impairing the process. Thus, this work seeks to promote a clening technique for the type CBN wheel, the grinding cylindrical AISI 4340 steel hardened and tempered, with the use of MQL. Through a device was placed in contact on the peripheral surface of the grinding wheel, rectangular rods compounds materials: Teflon, aluminum oxide and silicon carbide. The output variables of the process were analyzed the behavior of the tangential cutting force, surface roughness, acoustic emission, G ratio (volume of material removed/volume of wheel worn), in photos scanning electron microscope, hardness and roundness. The method MQL with the device was compared with the followin conditions of lubrication and cooling: Conventional; MQL without cleaning; MQL and cleaning air nozzle. Based on the results obtained, the cleaning method using the device with the bat silicon carbide, proved in some conditions to obtain better results and no thermal damage, compared to other methods / Mestre