Effect of diamond burnishing treatment parameters on eddy current displacement measurement

Eddy current sensors are commonly used in rotating machinery for condition monitoring by detecting shaft vibrations. These sensors measure the relative distance between the sensor and the shaft by inducing eddy currents on the surface of the shaft without physical contact, enabling the inference of shaft vibrations. The strength of the induced eddy currents correlates with the distance to the shaft. However, the strength of the eddy currents is also influenced by electrical properties. Electrical properties between the measurement points may vary, as the shaft rotates, potentially introducing measurement errors. Diamond burnishing treatment is a known and proposed method for reducing measurement errors by modifying the surface characteristics of the test piece. In this treatment, a rounded diamond is pressed against the surface as it moves. Hence, it enhances the surface, homogenizing residual stress, roughness, and microstructure more consistent across the treated area. There is a limited amount of published research on optimal parameters for diamond burnishing to minimize measurement errors. In this study, three force parameters were applied during diamond burnishing process, and their effects on measurement error across different shaft diameters were investigated. Results show that no single force parameter consistently produced the best outcomes. The diameter of test piece appears to have more effect on the measurement error than the force applied. The results also indicate that optimal force parameter varies with different diameters. The results of this study can assist companies in complying with strict standards for measurement error, enabling more efficient error minimization.