Cam-shafts used for internal-combustion engines need to be chilled at the foundry stage to increase the cam hardness, however, unexpected chilled structures may occur on the sensor plate surface. Chilled structures on the sensor plate may break a grinding tool during the grinding process and may also hinder the fabrication of a specified shape due to resistance arising from the hyper-hardness of the chilled structure. For this reason, developing an inspection technique and a device for detecting unnecessary chilled structures before the grinding process of cam-shafts is needed to determine the rejection and removal of a sample with chilled structures. This paper reports on a recently developed non-destructive method employing the Eddy Current method to detect chilled structures on a cam-shaft sensor plate accurately.

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