Técnica de diagnóstico da integridade superficial do rebolo durante o processo de dressagem baseada em imagens acústicas obtidas por diafragma piezelétrico
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Data
2019-05-24
Autores
Dotto, Fabio Romano Lofrano
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O processo de retificação é um processo amplamente utilizado para produzir formas complexas e tolerâncias precisas em peças que são necessárias especialmente para a fabricação de componentes de engenharia. A retificação é um processo de manufatura situado na parte final da cadeia de usinagem, consistindo em uma operação de remoção de material da superfície da peça usinada e utiliza como ferramenta de corte o rebolo. No decorrer do processo de retificação a ferramenta de corte sofre desgaste e com isso, torna-se necessária a realização do processo de dressagem, cuja finalidade é restaurar a eficiência de corte do rebolo. A grande dificuldade no processo de retificação consiste em identificar o momento correto para a realização da dressagem e, para isso torna-se necessária a realização do monitoramento da ferramenta de corte (rebolo). Neste contexto, no presente trabalho desenvolveu-se uma técnica inovadora de diagnóstico da integridade superficial do rebolo, durante o processo de dressagem, baseada em imagens acústicas obtidas por meio de diafragma piezelétrico. Para isso, foram realizadas marcas (falhas) em um rebolo e, posteriormente, realizados ensaios com várias profundidades de dressagem, coletando sinais por meio de um sensor de emissão acústica e de um diafragma piezelétrico. Com base nesses sinais, foram avaliadas bandas de frequência para a obtenção de imagens acústicas que representassem com maior fidelidade e nitidez as marcas impressas no rebolo. Por fim, ambos os sensores (emissão acústica e diafragma piezelétrico) foram comparados e estabelecida uma análise de resultados frente às condições de dressagem estudadas. Os resultados demonstraram que o uso do diafragma piezelétrico é eficiente para a obtenção de mapas acústicos da superfície do rebolo quando comparado com o sensor de emissão acústica e em algumas condições de usinagem obteve resultados superiores aos observados no monitoramento da ferramenta com o sensor de emissão acústica.
The abrasive machining process is a widely used process for producing complex shapes in work pieces and for providing precise tolerances that are especially required for the production of engineering components. Grinding is a manufacturing process placed at the end of the machining chain, consisting of an operation to remove material from the surface of the machined part and uses grinding wheels as a cutting tool. During the grinding process the cutting tool suffers wear and tear, and thus, it is necessary to perform the dressing process, whose purpose is to restore the cutting efficiency of the grinding wheel. The great difficulty in the grinding process is to identify the correct moment to perform the dressing, and for that reason, it is necessary to perform the monitoring of the cutting tool (grinding wheel). In this context, the present work made possible the development of an innovative technique to diagnose the surface integrity of the grinding wheel, during the dressing process, based on acoustic maps obtained through the piezoelectric diaphragm. Therefore, some patterns (marks) on a grinding wheel were performed and, later, tests were carried out with several dressing depths, acquiring signals from a commercial acoustic emission sensor and a piezoelectric diaphragm. Based on these signals, frequency bands were evaluated to obtain acoustic maps that represented with more fidelity and sharpness the marks inserted in the grinding wheel. Finally, both sensors (acoustic emission and piezoelectric diaphragm) were compared and a result analysis was established given the studied dressing conditions. The results showed that the use of the piezoelectric diaphragm was efficient to obtain acoustic maps of the grinding wheel surface when compared with commercial acoustic emission sensors and in some machining conditions even better results were obtained
The abrasive machining process is a widely used process for producing complex shapes in work pieces and for providing precise tolerances that are especially required for the production of engineering components. Grinding is a manufacturing process placed at the end of the machining chain, consisting of an operation to remove material from the surface of the machined part and uses grinding wheels as a cutting tool. During the grinding process the cutting tool suffers wear and tear, and thus, it is necessary to perform the dressing process, whose purpose is to restore the cutting efficiency of the grinding wheel. The great difficulty in the grinding process is to identify the correct moment to perform the dressing, and for that reason, it is necessary to perform the monitoring of the cutting tool (grinding wheel). In this context, the present work made possible the development of an innovative technique to diagnose the surface integrity of the grinding wheel, during the dressing process, based on acoustic maps obtained through the piezoelectric diaphragm. Therefore, some patterns (marks) on a grinding wheel were performed and, later, tests were carried out with several dressing depths, acquiring signals from a commercial acoustic emission sensor and a piezoelectric diaphragm. Based on these signals, frequency bands were evaluated to obtain acoustic maps that represented with more fidelity and sharpness the marks inserted in the grinding wheel. Finally, both sensors (acoustic emission and piezoelectric diaphragm) were compared and a result analysis was established given the studied dressing conditions. The results showed that the use of the piezoelectric diaphragm was efficient to obtain acoustic maps of the grinding wheel surface when compared with commercial acoustic emission sensors and in some machining conditions even better results were obtained
Descrição
Palavras-chave
Retificação, Monitoramento, Dressagem, Mapa acústico, Diafragma piezelétrico, Indústria 4.0, Internet das coisas, Grinding, Monitoring, Dressing, Acoustic map, Piezoelectric diaphragm, Industry 4.0, Internet of things