Abstract
Nitric acid etching, which is the conventional method used in manufacturing plants to detect grinding burn, has a number of problems as follows: (1) detection level varies depending on the operator and the equipment used; (2) the tested pieces must be scrapped as it is a destructive inspection; and (3) outflow of defective products cannot be prevented perfectly as 100% inspection cannot be carried out. This study was performed to develop a non-destructive inspection system to detect grinding burn, which can be used to perform quantitative 100% inspection within a production line. For this inspection, an eddy current sensor is selected because of its short measurement time and low cost. In this paper, a new method that simultaneously measures eddy currents of two different frequencies is proposed. This method reduces the misdetection of grinding burn by eliminating the effect of variance in base material.
