Separação de erros geométricos transversais ao barramento em torno horizontal: aplicação da reversão de artefato como método de calibração de erros
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Data
2021-07-16
Autores
Rocha, Guilherme Castilho Encinas da
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Universidade Estadual Paulista (Unesp)
Resumo
As máquinas-ferramentas são amplamente utilizadas para diversos tipos de manufaturas. Com a globalização e o exponencial desenvolvimento tecnológico, surge a necessidade de se produzir com o mínimo de erros e aumentar a qualidade. Para isso, é essencial que as máquinas que envolvem a usinagem desses produtos tenham seus erros conhecidos e controlados. (FAN et al., 2018). Existem diversas fontes de erros que podem estar relacionadas a essas máquinas. As reversões abrangem técnicas que permitem fazer a separação desses erros. Essas técnicas se caracterizam por uma manipulação mecânica, permitindo alterar o sinal da componente do erro. (EVANS; HOCKEN; ESTLER, 1996). Neste contexto, este projeto tem o objetivo de apresentar um método de separação de erros em um torno mecânico pelo método da reversão que permita identificar e simular desvios transversais ao barramento, em processos de torneamento de peças com diferentes comprimentos e diâmetros. Foram coletados dados através da medição da face do artefato metálico, em quatro posições de deslocamento do carro transversal do torno. Foram aplicados o método dos mínimos quadrados, para corrigir o desalinhamento das montagens, e o método de reversão do artefato, para separar o erro de retitude da barra e o erro de retitude do carro do torno. Os resultados mostram que os erros do carro variam para as diferentes posições transversais e que o erro máximo médio registrado é de aproximadamente 10 μm. Pôde-se perceber que o perfil de erro da barra apresentou desvios mais acentuados nas regiões centrais do artefato, decaindo nas extremidades, o que indica um erro caraterístico do processo de fabricação em que o mesmo foi produzido. Com a análise da variância, observou-se que a posição do carro influencia estatisticamente na grandeza do erro transversal para algumas posições. A medição do artefato na MMC permitiu comparar o perfil de erro do artefato obtido no experimento e se mostrou condizente, com erros mínimos de 2% a 6% entre os resultados. Deste modo, concluiu-se que o método de separação de erros proposto permitiu obter informações sobre o perfil de retitude do artefato e sobre o erro transversal ao barramento do torno e, a partir disso, realizar a compensação dos erros nos equipamentos utilizados para o processo de usinagem.
Machine tools are widely used for different types of manufactures. Due to the globalization and the exponential technological development, there is a need to produce with minimal errors and increase quality. Thereby, it is e ssential that the machines involved in the machining of these products have their errors known and controlled. (FAN et al., 2018). There are several error’s sources that can be related to these machines. Reversals cover techniques that allow errors separat ion to be done. These techniques are characterized by mechanical manipulation, allowing to change the sign of one error component. (EVANS; HOCKEN; ESTLER, 1996). In this context, this project aims to present a method of error separation in a lathe using th e reversal method that allows identification and simulation of transversal deviations from the busbar, in the process of turning parts with different lengths and diameters. Data were collected by measuring the face of a metallic artifact, in four displacem ent positions of the transverse lathe carriage. The least squares method was applied, to correct the misalignment of the assemblies, and the ruler reversal method, so that it was possible to separate the straightness error of the bar and the straightness e rror of the lathe carriage. The results allow denoting that the carriage errors vary for the different transverse positions and that the maximum error registered , in average , approximately 10 μ m. It could be seen that the error profile of the bar is presented more accentuated deviations in the central regions of the artifact, decreasing at the extremes, which indicates a characteristic error of the manufacturing process in which it was produced. With the analysis of variance, it was observed that the carriage position statistically influences the magnitude of the transversal error positions , for some . The measurement of the artifact in a MMC allowed to compare the error profile of the artifact obtained in the experiment and proved to be consistent, wit h minimum errors of 2% to 6% between the results. Ultimately, it was concluded that the error separation method proposed allowed to obtain information about the artifact's straightness profile and the transversal error to the lathe's busbar and, from this, to perform the error compensation in the equipment used for the process. of machining.
Machine tools are widely used for different types of manufactures. Due to the globalization and the exponential technological development, there is a need to produce with minimal errors and increase quality. Thereby, it is e ssential that the machines involved in the machining of these products have their errors known and controlled. (FAN et al., 2018). There are several error’s sources that can be related to these machines. Reversals cover techniques that allow errors separat ion to be done. These techniques are characterized by mechanical manipulation, allowing to change the sign of one error component. (EVANS; HOCKEN; ESTLER, 1996). In this context, this project aims to present a method of error separation in a lathe using th e reversal method that allows identification and simulation of transversal deviations from the busbar, in the process of turning parts with different lengths and diameters. Data were collected by measuring the face of a metallic artifact, in four displacem ent positions of the transverse lathe carriage. The least squares method was applied, to correct the misalignment of the assemblies, and the ruler reversal method, so that it was possible to separate the straightness error of the bar and the straightness e rror of the lathe carriage. The results allow denoting that the carriage errors vary for the different transverse positions and that the maximum error registered , in average , approximately 10 μ m. It could be seen that the error profile of the bar is presented more accentuated deviations in the central regions of the artifact, decreasing at the extremes, which indicates a characteristic error of the manufacturing process in which it was produced. With the analysis of variance, it was observed that the carriage position statistically influences the magnitude of the transversal error positions , for some . The measurement of the artifact in a MMC allowed to compare the error profile of the artifact obtained in the experiment and proved to be consistent, wit h minimum errors of 2% to 6% between the results. Ultimately, it was concluded that the error separation method proposed allowed to obtain information about the artifact's straightness profile and the transversal error to the lathe's busbar and, from this, to perform the error compensation in the equipment used for the process. of machining.
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Palavras-chave
Metrologia, Máquinas-ferramenta, Tornos mecânicos, Metrology, Machine tools, Lathe