Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 47).

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 149-151).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 144-148).

Profile waviness is one of the main causes for scrapped parts in precision bore grinding. Although efforts have been made to reduce its occurrence, the problem has not been eliminated completely. In production, the identification of a few scrapped parts in a lot of several thousands often requires expensive manual processes. Grinding machines used to produce these parts are usually equipped with measurement gage heads having tactile probes. Until now, these in-process gages have been used to measure only the average diameter of the part. This research focused on the use of these tactile probes to measure bore waviness in precision-ground parts. The first objective was to develop a post-process machine that performs automated measurement of the bore profile and is capable of detecting waviness. The machine was built using the same measurement system and the same roll-shoe centerless fixture as the grinding machines used for the production of the parts. The machine was designed and set up such that disturbances of the measurement are minimized. It was shown that the machine reaches accuracies close to those obtained by manually operated roundness machines. The cycle time is approximately 4 seconds per part compared to several minutes for manually operated roundness machines. As a second objective, the possibility of measuring waviness directly in the grinding machine was evaluated. Feasible design modifications to reduce the effect of disturbances are very limited in grinding machines, since interference with the grinding process must be avoided. Therefore, analytical methods were developed to reduce these effects and partly restore the original profile. The main disturbances that were addressed are errors due to irregular sampling of the profile, to the frequency response behavior of the gage heads, and to motion of the workpiece center relative to the gage heads. The post-process machine was used as a development and test platform for the analytical methods. To further verify these methods, tests were also conducted in an industrial grinding machine.

The diploma thesis deals with the issue of bearings noisiness. The bearings noisiness appears as a negative phenomenon in all the mechanical devices that generate any kind of movement. Analysis of this phenomenon enables to analyse the technical condition of the bearing and predict its defects as well. The theoretical part of the thesis is devoted to the vibration diagnostics and noisiness diagnostics, which are deeply linked. The practical part of the thesis deals with the real problem of the bearing’s noisiness in the engineering company. The main asset of this thesis is a design and successful implementation of the measures, which reduce noisiness of the selected type of the bearing.

A busca das empresas por uma solidez no mercado de trabalho competitivo desempenha um papel relevante na modernização dos processos produtivos, bem como no manuseio adequado das técnicas de cada processo. O processo de retificação centerless de passagem é bastante utilizado nas indústrias, principalmente para produção de grandes lotes de peças cilíndricas, que requerem tolerâncias dimensionais pequenas e superfícies com alto grau de acabamento. As retificadoras centerless são consideradas máquinas complexas devido ao grande número de fatores e parâmetros que influenciam a qualidade do produto e a estabilidade do processo. Mesmo com o avanço tecnológico, na prática industrial, na maioria das vezes, o processo de retificação centerless é determinado de modo empírico. Dentro desta situação é notável a escassez de livrostextos acerca do assunto, principalmente no tocante à definição de parâmetros de ajustagem de máquina. Este cenário tem intensificado a busca por soluções através de estudos sobre processos de retificação centerless. Nesse contexto, o presente trabalho tem como propósito estudar as correlações dos parâmetros envolvidos no processo de retificação centerless de passagem e a sua influência na qualidade final do produto, assim como, a elaboração de um software para determinar os parâmetros de usinagem necessários para ajuste desse tipo de máquina. Os ensaios realizados permitiram verificar a influência do ângulo de topo da régua de apoio, do ângulo de tangência e a freqüência natural da máquina na circularidade da peça. Analisando-se os resultados constataram-se os melhores ângulos de topo da régua de apoio e os ângulos de tangência para obter os menores valores do erro de circularidade. Verificou-se que é possível evitar peça no formato de uma oscilação harmônica, conhecendo-se a freqüência da peça e freqüência natural da máquina. / The search of the companies for a solid and competitive market, does with that they play an important part in the productive processes modernization, as well as in the correct handling of the techniques of each process. Now the Throught-Feed Centerless Grinding process is quite used in the industries, mainly for production of great lots of cylindrical pieces, that request tight dimensional tolerances and surfaces with high degree of finish. The Centerless Grinding are considered complex machines, due to the great number of factors and parameters that influence the product quality and the process stability. Even with the technological progress, in the industrial practices, the machining parameters for grinding are certain empirically and the Centerless Grinding machines adjusted and operated taking into account the "filling" of each operator. In this situation is notable the shortage of books-texts concerning the subject, mainly regarding machine parameters setup. Therefore, the incessant search of solutions exists through studies of Centerless Grinding processes. In this context the present work has as purpose to study the correlation between the parameter of the Throught-Feed Centerless Grinding process and the influence in workpiece accuracy, again software elaboration to determine all necessary machining parameters for adjustment of the Throught-Feed Centerless Grinding. The experimental studies were conducted permited to verify the influence of the work rest blande angle, the workpiece height and the machine frequency in the workpiece roundness error. The results showed what the most work rest blande angle and tangent angle for obtain the smaller workpiece roundness error. In relation to the machine requency, it has been verified workpiece roundness form when the workpiece frequency is same the machine frequency.

This master´s thesis deals with the measurement of surface roughness on a roundness instrument Talyrond TR595S. The aim was to expand possibilities of measuring on this roundness instrument. The main benefit of this thesis is creation of the proposal for the roughness measurement components in a horizontal and vertical plane. Thesis also includes the procedure for measuring of the roughness of the circular components including calculation of measurement uncertainty.

This study attempts to determine a relative age of the Wahianoa moraines, Mt Ruapehu using three relative age dating techniques: Lichenometry, Schmidt hammer and Boulder roundness. There were three study areas used, termed the Wahianoa ‘A’, ‘B’ and ‘C’ moraines. Upon determining a relative age for these moraines, their timing of their formation was placed within New Zealand’s glacial timescale. This is the first study of its kind conducted on Mt Ruapehu and has left the door open for more research in this field. The species of lichens measured on the Wahianoa moraines were Rhizocarpon subgenus, which the largest diameters were measured using callipers. A total of 606 lichens were measured in the Wahianoa Valley and were processed using the growth curve and size frequency methods. A lichenometric growth curve was constructed from lichens growing in the Ohakune cemetery. The dates derived from both methods placed the formation of the Wahianoa moraines during the Little Ice Age. An L-type Schmidt hammer was used on the boulders in the Wahianoa Valley. A total of 280 measurements were taken off the boulders on the Wahianoa moraines. The results of this method, when compared to Winkler’s (2005) study in the South Island placed the formation of the Wahianoa moraines pre-Little Ice Age. Although no definitive ages could be derived from this comparison due to differences in lithology between the two studies, it provided an idea as to where the formation of these moraines could belong. This is the first time that the Boulder roundness method has been used in New Zealand, having only been developed by Kirkbride (2005). This method was used to determine which of the ridges in the Wahianoa Valley were older. It was found that the Wahianoa ‘A’ moraines were the oldest in the valley followed by Wahianoa ‘B’ and ‘C’ respectively. A climate reconstruction was also conducted for the Wahianoa Valley to see what conditions may have been in existence during the formation of the Wahianoa moraines. The paleo-ELA for the Wahianoa Glacier was estimated using the Accumulation-Area Ratio (AAR), Terminus to Headwall Ratio (THAR), Maximum Elevation of the Lateral Moraines (MELM) and Extrapolation methods. The current ELA was estimated using the AAR, THAR and Extrapolation methods. The difference between these estimates was used to determine what temperature decrease would have caused the formation of the Wahianoa moraines. The average paleo-ELA was found to be c. 1715m, while the current ELA was found to be 2475m which lead to a 4.5°C decrease. This temperature decrease correlates well with that of the Last Glacial Maximum. This study found significant differences in relative age of the Wahianoa moraines. There are a number of factors that can affect the growth of lichens such as micro-environmentalconditions and the fact that a growth curve was constructed off site. Factors such aspetrography can affect the Schmidt hammer results and the Boulder roundness measurements. In addition, precipitation can affect the ELA values which can then cause the wrong placement within a glacial event. Further research lies in the use of the Schmidt hammer on a known age surface such as the Mangatepopo moraines which will aide in a better correlation of relative age. Also, further research using climate reconstructions on Mt Ruapehu and the effect of precipitation will also aide in a better correlation with a glacial event.

No description available.

Made available in DSpace on 2014-06-11T19:24:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-01-19Bitstream added on 2014-06-13T18:21:15Z : No. of bitstreams: 1 franca_tv_me_bauru.pdf: 6693171 bytes, checksum: a1e62f81ea86d1eeed97e598cb2bb8f5 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Atualmente, a fabricação é caracterizada pela sua complexidade, pluralidade de disciplinas e crescente demanda de novas ferramentas e técnicas para a solução de difíceis problemas. As redes neurais artificiais oferecem uma nova e diferente alternativa para investigar e analisar os desafiadores tópicos relacionados à manufatura. Desta forma, estudou-se neste trabalho os assuntos relacionados à aplicação das redes neurais na predição da circularidade e rugosidade da peça retificada pela análise de algumas variáveis de saída do processo. Foram empregados nos ensaios de usinagem: um fluido de corte (óleo emulsionável), um rebolo superabrasivo de CBN com ligante vitrificado e peças temperadas e revenidas de aço VC-131. Este trabalho também utilizou outras tecnologias de otimização do processo de retificação, tais como: a utilização de defletores aerodinâmicos para a quebra da camada de ar e a refrigeração otimizada por meio de um jato de fluido direcionado. Os ensaios de usinagem foram realizados para gerar a base de dados utilizada nos testes das redes neurais (ensaios computacionais). Fez-se portanto, diversos experimentos variando-se a velocidade de avanço, ou mergulho do rebolo na peça. As variáveis de saída analisadas que serviram de dados de entrada para a RNA foram: a força tangencial de corte (Ft), a energia específica de retificação (u), o desgaste diametral do rebolo, o parâmetro DPO e a emissão acústica (EA). A rugosidade e circularidade foram utilizadas para o treinamento das RNA s. Nos testes computacionais, foram analisadas duas bases de dados: a primeira referente às médias de todos os 40 ciclos de retificação, já a segunda utilizou todos os valores destes 40 ciclos. Ainda foram examinadas diferentes combinações de dados de entrada para verificar a influência do parâmetro DPO na predição. Os resultados... / Nowadays, the manufacturing is characterized by its complexity, plurality of subjects and increasing demand of new tools and techniques for the solution of difficult problems. Artificial neural nets propose a new and different alternative to investigate and analyze the challenging topics related to the manufacturing. The objective of this work is to study the use of artificial neural nets in the prediction of roundness and roughness of a ground workpiece. It was used a CBN wheel, emulsion oil and workpieces made of VC-131 steel. This work also used other technologies of grinding optimization, such as: the use of a coolant shoe to break the air curtain layer in addition and the high pressure fluid jet. Grinding tests had been carried through to generate the database used in the artificial neural nets (computational tests). Different feed rates were used in these experiments to generate outputs such as: tangential cutting force (Ft), specific energy of grinding (u), diametrical wear of the wheel, DPO parameter and acoustic emission (EA). The roughness and roundness were used to train the RNA's. In the computational tests, it was verify the influence of the DPO parameter in the prediction as well as two different databases. The results suggest that this parameter (DPO) was not able to substitute the tangential cutting force (Ft) and the acoustic emission (EA) in the prediction. Moreover, it was verify the need of an input that represents the dynamic stiffness of the machine-tool-workpiece system to improve the roundness prediction.