Impacto da adição de água no fluido de corte aplicado pela técnica de mínima quantidade de lubrificante na retificação
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Data
2021-05-27
Autores
Sato, Bruno Kenta
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Universidade Estadual Paulista (Unesp)
Resumo
A sustentabilidade está entre os principais temas do século XXI. A crescente busca pela redução dos impactos ambientais surgiu pela necessidade de preservação dos recursos naturais. Entende-se que a metodologia tradicional de lubrirrefrigeração, aplicada nos processos de usinagem, é prejudicial ao meio ambiente, saúde humana e representa uma porcentagem significativa dos custos do processo. A técnica de Mínima Quantidade de Lubrificante, desenvolvida para contornar essas desvantagens, demonstrou grande eficácia nos processos de usinagem com geometria definida. No entanto, limitações ocorrem durante sua aplicação no processo de retificação, visto que o mesmo necessita de alta refrigeração e limpeza da superfície de corte do rebolo, fatores em que a técnica de MQL é deficiente. Dessa forma, novas tecnologias devem ser desenvolvidas para possibilitar a aplicação da técnica na retificação. A adição de água no fluido de corte aplicado pela técnica de MQL tem a proposta de melhorar a refrigeração e lubrificação com baixo custo, além de minimizar os impactos ambientais. A aplicação do jato de ar em alta velocidade sobre a superfície de corte do rebolo possui o objetivo de aumentar a taxa de remoção de cavacos da superfície de corte do rebolo. A eficiência dessas tecnologias foi avaliada pela retificação do aço ABNT 4340 temperado e revenido utilizando rebolo de CBN com ligante vitrificado. Imagens de MEV e EDS da superfície de corte do rebolo auxiliaram no monitoramento do empastamento. A rugosidade média aritmética e desvios de circularidade foram os parâmetros para determinação da qualidade das peças; e a análise do cavaco auxiliou na determinação dos mecanismos de remoção de material. A adição de água na técnica de MQL reduziu a rugosidade superficial, minimizou os defeitos superficiais e melhorou a precisão geométrica do processo. O sistema de limpeza foi benéfico para a qualidade das peças, reduzindo em 35% a rugosidade superficial e 6% no erro de circularidade.
Sustainability is one of the most discussed topics of the century. The number of investigations to minimize the environmental impacts have been increasing by the necessity of natural resources preservation. The conventional methodology of lubri-refrigeration utilized on the machining process is prejudicial to the environment, harm to human healthy and it represents high percentage of industrial costs. The development of Minimum Quantity of Lubrication technique emerged to overcome the disadvantages of conventional application of cutting fluids. The MQL provided satisfactory results during its application on turning, drilling and milling, however, its application on grinding is difficult, since this process generates great amount of heat and it demands efficiency on the chips removal out of the tool cutting surface. Therefore, new technologies have to be developed to success on the MQL application on grinding. The addition of water on the cutting fluid of MQL technique proposes the improvement on the cooling effect of the technique with low costs and minimizing the environmental impacts, furthermore, the application of high-speed jet of air on the cutting surface has as goal rise the rate of chips being expelled out of the process. The efficiency of these technologies is going to be measured machining the AISI 4340 steel quenched and tempered, using CBN grinding wheel with vitrified bond. Images of SEM and EDS of the grinding wheel cutting surface supported on the clogging evaluation, the surface roughness and the roundness errors determined the workpiece quality, and the analysis of the chips assists the definition of the mechanism of material removal. The addition of water on the MQL technique improved the surface roughness and it ameliorate the superficial defects occurrence and geometric accuracy. The wheel cleaning system improved the workpiece quality, since it reduced in 35% the surface roughness and 6% the roundness error.
Sustainability is one of the most discussed topics of the century. The number of investigations to minimize the environmental impacts have been increasing by the necessity of natural resources preservation. The conventional methodology of lubri-refrigeration utilized on the machining process is prejudicial to the environment, harm to human healthy and it represents high percentage of industrial costs. The development of Minimum Quantity of Lubrication technique emerged to overcome the disadvantages of conventional application of cutting fluids. The MQL provided satisfactory results during its application on turning, drilling and milling, however, its application on grinding is difficult, since this process generates great amount of heat and it demands efficiency on the chips removal out of the tool cutting surface. Therefore, new technologies have to be developed to success on the MQL application on grinding. The addition of water on the cutting fluid of MQL technique proposes the improvement on the cooling effect of the technique with low costs and minimizing the environmental impacts, furthermore, the application of high-speed jet of air on the cutting surface has as goal rise the rate of chips being expelled out of the process. The efficiency of these technologies is going to be measured machining the AISI 4340 steel quenched and tempered, using CBN grinding wheel with vitrified bond. Images of SEM and EDS of the grinding wheel cutting surface supported on the clogging evaluation, the surface roughness and the roundness errors determined the workpiece quality, and the analysis of the chips assists the definition of the mechanism of material removal. The addition of water on the MQL technique improved the surface roughness and it ameliorate the superficial defects occurrence and geometric accuracy. The wheel cleaning system improved the workpiece quality, since it reduced in 35% the surface roughness and 6% the roundness error.
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Retificação, Sustentabilidade, Mínima Quantidade de Lubrificante, Adição de água, Sistema de limpeza com ar comprimido, Grinding process, Sustainability, Minimum Quantity of Lubrication, Addition of water, Wheel cleaning system with compressed air