Influence of the sheet metal Seebeck coefficient on wear detection based on thermoelectric measurement

The measurement of thermoelectric current is a new and effective method for inline wear detection in sheet metal forming. The measuring principle is based on the Seebeck effect, whose characteristic value, the Seebeck coefficient depends on the material composition. In the previous research of the authors, a boundary value of the thermoelectric value that separates the mild and severe wear was identified. Due to the large deviation of the Seebeck coefficient of the material used in sheet metal forming, it is worth discussing the influence of the Seebeck coefficient of the sheet metal material on the effectiveness and boundary value of the thermoelectric current for wear detection. In this paper, the measuring principle is first illustrated using an equation based on thermoelectricity. The Seebeck coefficients of the tools and sheet metals are then determined by a specifically designed device. At the same time, the wear tests for different materials are used to determine the boundary values for different tribological systems. Finally, the obtained Seebeck coefficient and boundary values are compared. From the results it can be concluded that the value of the measured Seebeck coefficients have a discernible effect on the boundary values, which provides a useful insight for inline wear diagnosis for practical applications.