This master’s thesis familiarizes reader with technology of machine grinding – it’s history, principle, general use, related tools, achievable parameters and kinematics of grinding process. The core of work is analysis of jig-grinder Hauser H45-400, it’s kinematics, machine technical data, options and accessories. Work concludes with technical and economical assessment of machining of several parts with this machine and compares results to alternative options of machining.

Advanced ceramics have long held the front of the list of promising materials for high-tech applications. The most common problem is the high cost of design, production and machining of advanced ceramics parts. The main sense of advanced ceramics processing techniques development is affordable, high-volume production. The dissertation is focused on SiC silicon carbide grinding. SiC is used in the design of machine parts due to its excellent properties The deep knowledge of the diamond wheel grinding process is important because it is one of the finishing methods and therefore has a direct impact on the quality and strength of the SiC parts. The key issue here is the overall surface quality of the parts after diamond wheel grinding and the knowledge of the factors that influence the surface quality. These include, in particular, grinding vibrations. The main purpose of the thesis is to create a system of specific scientific and technical information, which will allow applying optimal technological procedures in the processing of ceramic components. The theoretical part of the thesis contains an analysis of the current state of the art in the advanced ceramics machining area, detailed analysis of the ceramics grinding with diamond grinding wheels, signal analysis theory and analysis of surface quality assessment methods. The experimental part contains analysis and discussion of the results obtained during the monitoring of the silicon carbide grinding process with a diamond grinding wheel. Various diagnostic methods have confirmed the presence of vibrations at a frequency close to the speed frequency of the grinding wheel, which had a significant, negative effect on the samples surface quality. Vibration diagnostics has identified a specific source of vibration (clamping of the workpiece) and it has been removed subsequently.

This thesis is intended on modernizing of grinding operations in production cam shafts of injection pump. Existing technology, mainly special-purpose machines, will be replaced by modern CNC grinding machine. Further modernization will take place in the area of measurement, where existing measuring instruments cannot measure profile of cams. There will be used the new measuring machine, which will manage to measure necessary dimensions and tolerances.

In this work, there is described an abrasive process including technological terms with an identification of motions and a speed of grinding. Then there are described abrasive tools, machines, their distribution and description. Further technological factors on accuracy of abrasive process and some reached parameters of the accuracy and their statistic interpretation.

Commodity projection studies anticipate an exponential increase in copper demand and decreasein mill grade of deposits currently exploited globally. Most of this demand is driven by theindispensable use of copper in electrification and currently, the growing demand in the contextof the green transition. To meet this challenge while supplying society with copper, producerssuch as Boliden AB have plans for exploration and expansion projects to increase their reservesand in turn increase production through efficient measures. As grinding is a bottleneck to mineralprocessing and the most energy intensive, more efficient comminution systems are beingconsidered for environmental sustainability. These are required to have lower energyconsumption while achieving the required liberation or better for subsequent processing byflotation. Consequently, the literature review shows there is a research query on whether more can beexpected from comminution to optimise for downstream processing. With most publishedresearch being on particles with a P80 less than 100 μm, there exists a gap in investigating theeffect of grinding on flotation for coarser size fractions which this degree project focuses on.Importantly, it includes evaluating chalcopyrite liberation and flotation performance when usinga Novel Comminution Device. Three grinding mills were considered, a vertical roller mill (VRM),a Novel Comminution Device (NCD), with a rod mill as the reference mill. The scope of this studywas an analysis of the mill products’ particle size distribution, chalcopyrite liberation andinvestigation of the flotation performance of the products from the three mills. This was done ona Cu-Au-Ag ore from the Boliden Aitik mine in northern Sweden. Particle size distribution (PSD) analysis revealed that at comparable P80 values, the VRMproduced particles had broader PSD curves than the rod mill, while the NCD provided a steeperproduct size distribution than its reference rod mill products. The chalcopyrite liberation analysisusing QEMSCAN automated mineralogy showed that for samples split into three size fractions, -45 μm, +45/-90 μm and +90 μm, the VRM and rod mill products had their highest proportion offree to liberated particles within the intermediate size fraction while for the NCD sample this waswithin the fine fraction. Overall, the NCD product had the highest free to liberated particles acrossall fractions. From shape analysis based on scanning electron microscopy (SEM) images, it wasobserved that the NCD produced particles with the higher elongation than the VRM and rod mill. The flotation performance was assessed with respect to the mass pull, kinetics, grade andrecovery in the concentrate and separation efficiency. The rougher batch flotation tests indicatedthat flotation of the VRM ground samples had higher mass pull, Cu recovery, faster kinetics andlower Cu grade than the samples from the reference rod mill. This was also a similar outcome forthe NCD with the exception of higher mass pull at an increased collector dosage in the rod millcase. For all the mills, the general trend showed that an increase in P80 was associated withreduced mass pull. Overall, at similar flotation conditions, despite having one of the coarsest P80s,the NCD product showed the fastest Cu recovery kinetics, highest total recovery and selectivityindex. The rod mill reference test samples gave the highest grade but the lowest recovery. The findings illustrate that there is a significant difference in PSD broadness between productsfrom different mills at comparable P80. The differences in flotation performance between thethree mill products were mainly attributed to differences in liberation, potential differences insurface activation between wet and dry grinding methods and to some extent, steepness of thePSD curve. Based on the high recovery yet low grade of the NCD ground product, this is best suitedfor the rougher flotation stage. Future studies should therefore include cleaner stage flotation andoptimisation tests for the NCD with respect to reagent dosages and hydrodynamic conditions.

Submitted by Alan Rodrigo de Sales null (alanestado@hotmail.com) on 2017-01-30T19:31:15Z No. of bitstreams: 1 Mestrado Alan Sales.pdf: 3094814 bytes, checksum: 40ab5a77d5ee1153c2e541c020d3ca6c (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-03T16:06:14Z (GMT) No. of bitstreams: 1 sales_ar_me_bauru.pdf: 3094814 bytes, checksum: 40ab5a77d5ee1153c2e541c020d3ca6c (MD5) / Made available in DSpace on 2017-02-03T16:06:14Z (GMT). No. of bitstreams: 1 sales_ar_me_bauru.pdf: 3094814 bytes, checksum: 40ab5a77d5ee1153c2e541c020d3ca6c (MD5) Previous issue date: 2016-12-09 / A aplicação da mínima quantidade de lubrificante (MQL) na usinagem dos metais começaram a ser estudados como alternativa para reduzir o uso dos fluidos de corte, para poder atingir uma produção mais limpa e menos prejudicial ao meio ambiente e aos trabalhadores, na retificação, apesar de ser considerada uma técnica inovadora no aspecto ambiental, sua aplicação é restrita devido à geração excessiva de calor e ao entupimento dos poros do rebolo causado pelos cavacos, e isto prejudica a qualidade final do produto e aumenta o desgaste da ferramenta. Esta pesquisa buscou aprimorar o uso do MQL utilizando óleo solúvel sintético da Quimatic Tapimatic ME-2. Além de usar o jato com a mistura ar e óleo e proporções de água injetado na interface rebolo-peça à alta velocidade um jato de ar comprimido, foi utilizado na superfície de corte do rebolo para minimizar o empastamento do rebolo gerado durante o processo de usinagem pela mistura formada pelo óleo do MQL mais os cavacos. Foram realizados ensaios na retificação cilíndrica externa de mergulho do aço ABNT 4340, temperado e revenido com dureza média de 54 HRC, usando rebolo de nitreto de boro cúbico (CBN) com ligante vitrificado. Os métodos de lubri-refrigeração propostos foram o convencional com fluido em abundância e o MQL (sem limpeza da superfície de corte do rebolo) e MQL (com a limpeza, utilizando o ângulo de incidência do ar comprimido na superfície de corte do rebolo fixo a 30 graus). Este ângulo foi escolhido por ser a melhor condição mostrada nos trabalhos de outros autores. Consideraram-se as variáveis de saída do processo: rugosidade, desgaste diametral do rebolo, circularidade, além de análises metalográficas e medições de microdureza da superfície retificada para verificação de danos térmicos; de forma a analisar a viabilidade da substituição do tradicional método de aplicação dos fluidos em abundância pelo MQL com a limpeza. Os resultados mostraram a possibilidade de implementação da técnica da limpeza do rebolo como um aprimoramento tecnológico da mínima quantidade de lubrificante na retificação, reduzindo o consumo dos fluidos de corte. A técnica MQL com limpeza para um ângulo específico de incidência do ar comprimido mostrou-se extremamente eficiente com a obtenção de melhor acabamento superficial e dimensional, além de menor desgaste da ferramenta abrasiva e isenção de danos térmicos, quando comparada com os métodos convencionais sem a limpeza do rebolo. / The application of minimum quantity of lubricant (MQL) on machining of metals has emerged as an alternative to reduce the abundance of cutting fluids and then achieve a cleaner production. In grinding, although considered a breakthrough technique in the environmental aspect, its application is restricted due to excessive generation of heat and grinding wheel loading caused by the chips, damaging the final product quality and increasing tool wear. The objective of this research was to improve the MQL technique synthetic soluble oil Quimatic Tapmatic ME-2 using beyond the jet with air mixture and oil and water proportions using an additional jet of compressed air to clean the clogged pores of the wheel. Grinding wheel in tests were performed in cylindrical plunge grinding of the ABNT 4340 steel, quenched and tempered (54 HRC), with a vitrified cubic boron nitride (CBN). The suggested methods of lubrication were conventional (abundant fluid), MQL (that without the use of air jet to cleaning the wheel) and MQL plus cleaning system using the angle of incidence of the compressed air on the cutting surface of the grinding wheel fixed to 30 degrees. Other autors chose This angle to be the best condition shown in the works. This performance was evaluated based on an analysis of the process output variables: roughness, diametric wear of the grinding, roundness, and metallographic analysis plus microhardness measurements of the grounded surface to verify thermal damage incidence. The results showed the possibility of implementing the technique of cleaning as a technological enhancement to minimum quantity of lubricant in the grinding, reducing the use of cutting fluids. The technique MQL plus cleaning system, in a specific incident angle of the compressed air was extremely efficient, resulting in better surface finish, reduced tool wear and free of thermal damage when compared with conventional methods without cleaning of the wheel.

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.

This thesis covers the process of automating the design of coolant nozzles used for cylindrical grinding. Coolant nozzles are used to supply coolant, an oil and water mixture used to cool the metal workpiece and lubricate the grinding wheel. In the automotive industry, grinding is used to reduce the surface roughness of the workpiece. However, a large amount of heat is generated, risking the heat treatment of the steel to be compromised, for this, coolant is supplied to minimize the heat caused by friction. A nozzle is used, aiming a jet to the zone that generates heat. Commonly used nozzles are adjustable, leading to variation in cooling performance if misaligned. The design of fixed nozzles is developed in this thesis to reduce variation and automatise the design for multiple applications. The automatically designed nozzles are fused deposition modeled and tested. The design automation tool is tested repeatedly and improved successively in the span of the thesis. This lead to a great extent of implementation of design automation. Which lead to a facilitation in reaching of the work zone and avoid obstacles. Also, the tool managed to create nozzle tubes for a multitude of machines. The tool is able to generate, aim, orient, and individually dimension multi-nozzle tubes. Design of Experiment methodology is implemented to find nozzle designs with improved velocity and flow rate and minimize the air mixture with the coolant. Several nozzle designs are tested and fitted into a surrogate model that is, in turn, optimized. The results of the tests led to a greater understanding of how the nozzle geometry restricts the flow rate when attempts of reaching higher velocities of the coolant jet are made. The surrogate models created, also made it possible to find the range of designs which best suits different applications, whereby a Pareto front was able to be populated with a range of different designs alternating in flow rate, velocity and coherency ratio.

O presente trabalho trata da análise experimental de um sistema de monitoramento baseado na técnica de fusão de sensores, aplicado em uma retificadora cilíndrica externa. A fusão é realizada entre os sinais de potência e emissão acústica para obtenção do parâmetro FAP (Fast Abrasive Power) através do método desenvolvido por Valente (2003). Através da simulação de problemas encontrados nos processos de retificação (falha de sobremetal, colisão, desbalanceamento e vibração), foram captados os sinais de potência e emissão acústica e a partir destes gerado o parâmetro FAP, comparando seu desempenho, na detecção dos problemas, com os outros dois sinais. Para a análise foram construídos os gráficos das variações dos sinais em relação ao tempo de execução do processo e os mapas do FAP e acústico. O sistema de monitoramento avaliado tem como característica baixa complexidade de instalação e execução. Os dados experimentais revelam que o FAP apresenta uma velocidade de resposta maior que a potência e levemente amortecida em relação à emissão acústica. O nível do seu sinal é igual ao da potência mantendo-se homogêneo durante o processo, ao contrário da emissão acústica que pode ser influenciada por diversos outros parâmetros, tais como geometria da peça, distância do sensor, montagem do sensor, entre outros, que independem da interação ferramenta-peça. O resultado é uma resposta dinâmica e confiável, associada à energia do sistema. Estas características são interessantes para o monitoramento de processos de retificação (excluindo a dressagem) sendo superiores àquelas apresentadas isoladamente pelos sinais de potência e emissão acústica. / The present study deals with an experimental analysis of a monitoring system based on a sensor fusion strategy applied to a cylindrical grinding machine. It comprises a fusion of the power and acoustic emission signals and has as main goal to obtain the FAP (Fast Abrasive Power) using the method developed by Valente (2003). Initially, the power and acoustic emission signals were captured under operational dysfunction conditions during the grinding process (stock imperfection, collision, unbalancing e vibration). Then, based on these signals, the FAP parameter was generated and its capability in characterizing operational dysfunctions evaluated against the performance of an individual analysis of the power and acoustic emission signals. For this analysis, FAP and acoustic maps plus plots showing the FAP signals vs. working time were implemented. The experimental data revealed that the FAP presents a faster response than the power signal and a slightly dumped response when compared against the acoustic signal. The signal level of the FAP is similar to the power signal and is homogenous during the machining process. On contrary to the FAP, the acoustic emission signal may be affected by parameters that are not related to the tool-workpiece interactions, workpiece geometry and sensor positioning. The dynamic response of FAP is reliable and linked to the energy of the system. Finally, it should be highlightened that the monitoring system based on the FAP parameter presents low complexity in both implementation and execution. Such characteristics are superior to those observed when using either the power or acoustic emission signals and highly valuable in a system designed to monitor grinding processes.

Made available in DSpace on 2014-06-11T19:31:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-10-19Bitstream added on 2014-06-13T18:41:35Z : No. of bitstreams: 1 alves_mcs_dr_bauru.pdf: 4541684 bytes, checksum: 03e1d27ea6b721a409bebc9862b0e67f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / É analisada a influência das técnicas de mínima quantidade de lubrificante (MQL), refrigeração otimizada e refrigeração convencional, com diferentes vazões e velocidade de aplicação do fluido de corte, na qualidade das peças produzidas (acabamento, erros de forma, trincas, queima, perda da dureza) com aços endurecidos, no processo de retificação cilíndrica externa de mergulho com a utilização de rebolos superabrasivos com baixa concentração de CBN. Utilizou-se fluidos de corte de origem vegetal, que representam menos riscos à saúde e ao meio. A análise da qualidade das peças foi realizada através da avaliação das variáveis de saída do processo como o comportamento da força tangencial de corte, energia específica de retificação, rugosidade, desvio de circularidade, emissão acústica, tensão residual, análise de microscopias eletrônicas de varredura e microdureza. Com a análise das formas de aplicação e das várias vazões e velocidades do fluido de corte utilizadas encontraram-se condições de lubri-refrigeração que propiciam a diminuição do volume de fluido de corte, diminuição do tempo de usinagem sem prejudicar os parâmetros geométicos, dimensionais, o acabamento superficial e a integridade superficial dos componentes. Em relação as diferentes formas de aplicação do fluido de corte notou-se o melhor desempenho da aplicação otimizada para maiores velocidades mostrando a eficiência de um novo conceito de bocal utilizado. O processo otimizado e o processo MQL foram capazes de manter a dureza superficial e a integridade superficial das peças produzidas. Exceção somente para a condição MQL com vazão de fluido de corte de 40ml/h que produziu trincas e retêmpera superficial. O desvio de circularidade e a rugosidade proporcionada pelos métodos estão dentro de valores recomendados para a retificação sendo que a técnica otimizada... / The influences on surface integrity of the parts (finishing, geometrical errors, cracks, burn, microhardness) and grinding wheel (wear) have been analyzed in this research by employing the minimum quantity of lubrication (MQL), optimized and conventional cooling for hardened parts of steel and superabrasives grinding wheel in the cylindrical plunge grinding process. This study was carried out through the assessment of the process output variables such as the behavior of the tangential cutting force, specific energy, surface roughness, circularity errors, acoustic emission, residual stress, scanning electronic microscopy (SEM) and microhardness. The cutting fluid derived from vegetal oil has been utilized in order to comply with the environmental requirements and thus offering less risk to the health. It could be observed from the analysis on different ways of cutting fluid applications that there are cooling conditions which facilitate the decrease in cutting fluid volume, decrease in grinding time without impairing the geometrical and dimensional parameters, the surface finish and surface integrity of the parts. It could be noted the optimized application for higher velocities has presented the best performance regarding the different applications of cutting fluids. The optimized and MQL processes were able to maintain the hardness and surface integrity of the ground parts. Exception occurend only for MQL condition with flow rate of 40ml/h, which led to cracks and quench on the workpiece surface. Roundness errors and surface roughness are within recommended valus for grinding with the best results obtained for the optimized method (2'mü' for roundness error and 0.5'mü'm for surface roughness) compared with the MQL technique (6.8'mü'm for roundness error and 1.2'mü'm for surface roughness). The process of minimum quantity of lubrication, however, has showed possible... (Complete abstract click electronic access below)