In this study, two sizes of diamond grinding wheels which are the diameter of 3 mm with thickness of 0.2 mm and the diameter of 1 mm with thickness of 0.1 mm are fabricated by a creative composite electroforming method. The pure nickel metal is set as anode. The micro cylindrical bar of tungsten carbide acted as spindle of the micro diamond grinding wheel, which is inserted into the hole of ABS mold and the conducting layer pre-coated on the local surface of ABS mold are set as cathode. The nickel sulfate bath mixing a constant amount of diamond particle is selected as electrolyte bath. At the current density of 2.5 ASD, the nickel-diamond composite layer with a constant thickness is electrodeposited on the ABS mold. When the ABS mold is dissolved by using acetone liquid, then the nickel-diamond composite layer could be used as the micro diamond grinding wheel is obtained. Moreover, in the study, the effects of electroforming method, composition of the electrolyte and current density on the surface quality of nickel-diamond composite layer are investigated. From the experiment results, it can be know that at the current destiny of 2.5 ASD, the covered area of diamond particle in this composite layer is 54.19% using the external hanging pump. And the flatness on the surface of this composite layer electroformed in the nickel sulfamate bath is better than that in nickel sulfate bath.

No description available.

For the requirements of high-speed signal transmission has been increasing, the fiber array in the communication system has a lot of advantages which can not be replaced. But the loss of coupling efficiency is a difficult problem as the distance of communication is getting longer and longer. For the sake of solving this problem, the system needs to use optic amplifier for enlarging the coupling efficiency in every long distance. The receiver can receive the correct signal by using optic amplifier. In order to reduce the using amount of optic amplifier for decreasing the cost, producing the fiber array with high coupling efficiency can reach the goal. This paper chooses quadrangular-pyramid-shaped fiber endface (QPSFE) which has better coupling efficiency than flattened-end fiber to research. Among those different manufacturing methods and different precision for fiber array packaging, the research chooses the method of grinding to manufacture the shape of surface. The research can raise the accuracy of manufacture for increasing the coupling efficiency of QPSFE by external equipments.

In this work, measurements and simulations were used to investigate the effects of grinding wheel topography on the geometric aspects of the grinding process. Since existing methods for measuring the grinding wheels were either not accurate enough or could only measure a small portion of a grinding wheel, a novel grinding wheel measurement system was developed. This system consists of a white light chromatic sensor, a custom designed positioning system and software. The resulting wheel scanning system was capable of measuring an entire grinding wheel with micron level accuracy. The system was used to investigate the effects of fine, medium and course dressing on grinding wheel surface topology and the resulting workpiece surface. New techniques were also developed to simulate metal removal in grinding. The simulation software consisted of a stochastic wheel model, dressing model and metal removal model. The resulting software could determine the uncut chip thickness, contact length for every cutting edge on a grinding wheel as well as the resulting surface roughness of the grinding wheel. The simulation was validated by comparing the wheel model used in the simulation to grinding wheel measurements and by comparing the simulated surface finish to the measured surface finish. There was excellent agreement between the predicted and experimentally measured surface topology of the workpiece. The results suggested that only 22 to 30% of the cutting edges exposed on the grinding wheel are active and that the average grinding chip is as much as 10 times thicker and 5 times shorter than would be produced by a grinding wheel with a regular arrangement of cutting edges as assumed by existing analytical approaches.

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.

Grinding is a critical manufacturing process and is often the only alternative when producing precision components or when machining brittle materials such as ceramics. Characterizing and modeling the surface finish in the grinding process is a difficult task due to the stochastic nature of the size, shape and spatial distribution of abrasive grains that make up the surface of grinding wheels. Since the surface finish obtained in grinding is a direct function of the wheel surface topography, which is conditioned by a single point dressing process, understanding the effects of dressing parameters on the wheel topography is essential. Therefore, the main objectives of this thesis are: 1) to experimentally characterize the three-dimensional surface topography of a conventional grinding wheel including attributes such as the abrasive grain height distribution, grain geometry and spacing parameters and their respective statistical distributions, 2) to determine the effects of single point dressing conditions on the three-dimensional wheel surface topography parameters and their distributions, 3) to model and simulate the three-dimensional wheel surface topography, and 4) to experimentally validate the wheel topography model. In this research, new and existing characterization methods are used to characterize the wheel surface and the individual abrasive grains. The new techniques include the use of X-ray micro-tomography (μCT) to obtain a better understanding of the grinding wheel's internal micro-structure, and a focus variation based optical measurement method and scanning electron microscopy to characterize previously ignored attributes such as the number of sides and aspect ratio of individual grains. A seeded gel (SG) vitrified bond conventional grinding wheel is used in the study. A full factorial design of single point wheel dressing experiments is performed to investigate the effects infeed and lead dressing parameters on the grinding wheel surface topography. A custom wheel indexing apparatus is built to facilitate precision relocation of the grinding wheel surface to enable optical comparison of the pre- and post-dressing wheel surface topography to observe wheel surface generation mechanisms such as macro-fracture and grain dislodgement. Quantitative descriptions of how each dressing parameter affects the wheel surface characteristics are given in terms of the wheel surface roughness amplitude parameters (Sp, Ssk, Sku) and areal and volume parameters (Spk, Sk, Vmp, Vmp, Vvc, Smr1) derived from the bearing area curve. A three-dimensional wheel topography simulation model that takes as input the abrasive grain height distribution and the statistical distributions for the various abrasive grain geometry parameters is developed and experimentally validated. The results of wheel characterization studies show that the actual abrasive grain height distribution in the SG wheel follows a beta distribution. The μCT work shows that the abrasives are polyhedral in shape, as opposed to the spherical or conical shapes commonly assumed in grinding literature. Grain spacing is found to follow a beta distribution while the number of sides of the grain and the grain aspect ratio are found to follow the gamma and the Weibull distribution, respectively. The results of the dressing study show that the lead dressing parameter has the strongest effect on wheel topography. Using statistical distributions for the key parameters (e.g. grain height, number of sides, grain spacing), a stochastic three-dimensional model is developed to simulate the wheel surface topography under different dressing conditions. The resulting model is shown to yield realistic results compared to existing models mainly due the fact that additional abrasive grain geometry parameters and more realistic assumptions of the different grain attributes are used in the model. It is shown that the model follows the overall wheel surface topography trends during dressing but has difficulty in accurately simulating some of the wheel characteristics under specific dressing conditions. The thesis then concludes with a summary of the main findings and possible future research avenues including extending the model to rotary dressing and simulation of wheel-workpiece interaction.

No description available.

The aim of the diploma thesis was to analyze qualitative outages in the production of gears for a gear pump and to minimize them. The largest amount of outages was caused by the burning of the surface during face grinding. After analyzing the current state of production there were created some suggestions to avoid this issue. Also there was found some space to speed up the whole process. Suggestions to eliminate burning have been tested with minimal impact on production. The reduction of outages for burned surface was achieved and also the cycle time was shortened. Those suggestions will be implemented in serial production.

Submitted by Rodrigo de Souza Ruzzi null (rodruzzi@me.com) on 2017-03-08T14:44:37Z No. of bitstreams: 1 DISSERTAÇÃO_Rodrigo_Ruzzi.pdf: 21281490 bytes, checksum: 10fa99d212e46ed1283477b7d4f4821b (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-03-13T14:22:28Z (GMT) No. of bitstreams: 1 ruzzi_rs_me_bauru.pdf: 21281490 bytes, checksum: 10fa99d212e46ed1283477b7d4f4821b (MD5) / Made available in DSpace on 2017-03-13T14:22:28Z (GMT). No. of bitstreams: 1 ruzzi_rs_me_bauru.pdf: 21281490 bytes, checksum: 10fa99d212e46ed1283477b7d4f4821b (MD5) Previous issue date: 2017-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Em meio à atual busca por adequações dos processos produtivos em função da saúde humana e preservação do ambiente, sem abrir mão da preocupação com os custos e a qualidade dos produtos, é preciso pesquisas a tentar novas técnicas de lubri-refrigeração eficientes como alternativas às convencionais. Assim, busca-se técnicas modernas que possam substituí-las, nesse sentido, a técnica MQL (Mínima Quantidade de Lubrificante) vem sendo uma alternativa pois utiliza baixo fluxo de óleo com ar em alta pressão, diminuindo a quantidade de resíduos gerados no processo. A técnica de MQL já se consolidou no mercado como solução para determinadas operações de usinagem como a de torneamento, porém encontra dificuldades no processo de retificação devido à formação de uma “borra” de óleo com cavacos que se forma na superfície do rebolo prejudicando os resultados do processo. A fim de superar este desafio, foi desenvolvido um sistema de ar comprimido para promover a limpeza da superfície do rebolo através da retirada da camada de borra ou resíduo que se impregna a ele durante o processo de retificação com MQL. Assim, o presente trabalho visou a análise do desempenho dos fluidos biodegradáveis LB 1100 (óleo puro) e BIOCUT 9000 (diluído em água na proporção de 1:5) aplicados a zona de corte via técnica de MQL com um sistema auxiliar de limpeza da superfície de corte do rebolo, em relação à técnica convencional. Os ensaios de retificação cilíndrica externa de mergulho foram realizados no aço endurecido ABNT 4340 utilizando um rebolo convencional de óxido de alumínio. Foram avaliados três avanços radiais distintos, 0,25, 0,50 e 0,75 mm/min. O desempenho da técnica MQL com sistema de limpeza foi avaliado com base nos parâmetros de rugosidade, desvios de circularidade, potência de usinagem, desgaste diametral do rebolo, microdureza e micrografia. Os resultados mostraram que a usinagem com a técnica MQL com o sistema de limpeza da superfície do rebolo e fluido LB 1100, de modo geral, proporcionou um desempenho superior às demais técnicas nas mesmas condições analisadas, apresentando peças sem danos, com os melhores valores de Rugosidade (Ra) e desvios de circularidade e com o menor consumo de potência e rebolo, ressaltando o potencial do uso desta técnica no processo de retificação. / Currently seeking for suitability of the production processes due to the preservation of the environment and human health, without abandoning the concern with cost and quality of products, research is needed to try new efficient cooling-lubrication techniques as alternatives to conventional ones. Thus, modern techniques are sought to replace them, in this way, the MQL (Minimum Quantity of Lubricant) technique has been an alternative because it uses low oil flow with high pressure air, reducing the amount of waste generated in the process. The MQL technique has already consolidated itself in the market as a solution for certain machining operations such as turning, but it encounters difficulties in the grinding process due to the formation of an oil slurry with chips that forms on the surface of the grinding wheel, damaging the results of the process. To overcome this challenge, a compressed air system has been developed to promote the cleaning of the grinding wheel surface by removing the layer of sludge or residue which is impregnated thereto during the grinding process with MQL. Thus, the present research had as objective the performance analysis of the biodegradable fluids LB 1100 (pure oil) and BIOCUT 9000 (diluted in water in a ratio of 1:5) applied to the cutting zone through the MQL technique with an auxiliary cleaning system of the grinding wheel cutting surface, in relation to the conventional technique. External cylindrical plunge grinding trials were performed on AISI 4340 hardened steel using a conventional aluminum oxide grinding wheel. Three distinct feed rates were evaluated: 0.25, 0.50 and 0.75 mm/min, respectively. The performance of the MQL technique with the cleaning system was evaluated based on the parameters of roughness, roundness error, grinding power, diametric wheel wear, microhardness and micrograph. The results showed that the machining with the MQL technique with the grinding wheel cleaning system and the fluid LB 1100, in general, provided the best performance in relation to the other techniques in the same analyzed conditions, presenting parts without damages, with the best values of roughness (Ra) and roundness error and with the lowest expenditure of power and wheel wear, highlighting the potential of the use of this technique in the grinding process.

Made available in DSpace on 2014-06-11T19:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-24Bitstream added on 2014-06-13T18:34:25Z : No. of bitstreams: 1 damasceno_rf_me_bauru.pdf: 2382441 bytes, checksum: c07ae566c39a8420db844725306f470e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve o propósito de contribuir com informações sobre a aplicação de fluidos de corte na operação de retificação plana de aço, em especial do ano ABNT 4340 temperado e revenido. Desta forma testados e comparados três métodos de lubri-refrigeração, os quais são: MQL (Mínima Quantidade de Lubrificante), convencional e otimizado. Os testes foram realizados em retificadora plana universal, utilizando um rebolo de cBN Vitrificado. Os fluidos de corte utilizados para os testes foram: emulsão com diluição a 5% para os métodos convencinal e Otimizado, enquanto que para MQL utilizou-se fluido sintético. A fim de obter uma análise comparativa dos desempenhos entre os três métodos, o parâmetro profundidade de corte foi variado em três valores (0,02mm;0,05mm e 0,08mm). Os outros parâmetros de corte, os quais foram mantidos constantes. Como variáveis de saída foram analisadas: força tangencial de corte, rugosidade, desgaste diametral do rebolo, relação G, dureza por microindentação, tensão residual superficial da pela e imagens obtidas no Microscópio Eletrônico de Varredura foram também obtidas para analisar a superfície das peças usinadas. Os resultados indicaram que a técnica MQL, permite obter menor desgaste diametral do rebolo, no entanto há prejuízos quanto ao acabamento superficial (rugosidade) em profundidades de corte até 0,05mm, acima deste valor o método MQL mostrou-se incapaz de realizar a lubrirefrigeração de forma eficaz. Já o método otimizado permitiu obter os melhores resultados de rugosidade, menor desgaste diametral do rebolo e induziu menor tensão residual superficial, mas em profundidade de corte de 0,02mm apresentou os maiores valores de força de corte tangencial comparados aos outros métodos. Por fim, o método convencional apresentou resultados medianos em quase todas as variáveis de saída analisadas / This work aims to investigate the comparative efficiency of three different colling and lubrificatins system e applied to surface grinding operation. Systems compared are MQL (Minimal Quantify Lubrification), conventional and conventional optimized. Grinding tests were performed on universal grinding machine using a vitrified cBN grinding wheel for grinding, steel samples of ABNT4340 (grade SAE4340) hardened and tempered to 55HRc. The cutting fluid used for testing was soluble oil at 5% for methods and conventional and conventional optimized and synthetic fluid for MQL technique tested. In order to obtain a comparative analysis of performance among the three methods, the depth of cut parameter was varied in three values (0,02mm, 0,05 mm, 0,08mm), the other cutting parameters were kept constant. Which one output variables investigated were: tangential cutting force, surface roughness, wheel diametrical wear, G ratio, workpiece microhardness and surface residual stress. Images obtained by scanning electron microscopy of the ground surface were used to analyze machined surfaces. The results indicated that the MQL technique allowed to prolong tool life of wheel, however there is damage on the surface finish of machined surfaces (roughness) at depths of cut up values to 0.05 mm. Above this value the MQL method proved did not provide efficiente lubrification and cooling functions. Conventional optimized method showed the best results of roughness, residual stress and least wear of wheel, bur in depth of cut 0.02 mm gave the highest values of tangential cutting force compared to other methods under conditions investigated. Finally, the conventional coolant method presented relatively satisfatory results for most output variables analyzed