Tool Condition Monitoring From Workpiece Surface Using an Eddy Current Probe

Eddy current probes are common in various applications, such as nondestructive testing, displacement measurement, and condition monitoring. However, they have not been extensively applied to machining tool condition monitoring. The present study addresses this gap. This study investigates tool condition monitoring method using an eddy current probe. Eddy current probe is used to scan face milled surfaces and the tool condition is inferred from the probe response. 2 probes with different shapes were used, a round-shaped coil and a racetrack-shaped coil. The probes are used to scan surfaces milled using face milling inserts with different wear states. The insert wear is determined from the eddy current probe responses that were processed by filtering and Discrete Fourier Transform. Peak height of the resulting frequency spectra was used to determine the tool condition. The results indicate that the method is suitable for tool condition monitoring. In general, the response peak height increased as the inserts were more worn. The results also show that eddy current probe shape has significant influence to the wear measurement. The racetrack coil was significantly more sensitive for wear measurement compared to the round coil. Future studies could investigate the use of different coil configurations, such as reflection probes or probe arrays.