Detection of microdefects in multilayer ceramic capacitors using the instantaneous frequency in the electromechanical response

초록

This paper proposes a novel signal processing method using electromechanical (EM) responses to collect pristine multilayer ceramic capacitors (MLCCs). EM response in MLCCs has shown its technical potential for nondestructive defect detection. However, due to the low sensitivity to micro defects (<100 mu m) in the conventional approaches, the practical applications of the EM response have been restricted. Therefore, we propose a novel signal-processing method that screens pristine MLCCs using EM responses. The algorithm, referred to as the oscillation rate of the instantaneous frequency, was used to differentiate between pristine and defective MLCCs. This method was first validated through time-domain numerical analysis with some damage scenarios, followed by the actual tests with 200 MLCCs collected from a failure lot. Finally, we could separate approximately 18 % of the MLCCs into the salvageable sample group with a low p-value (<0.005). The proposed methodology enables reliable screening pristine MLCCs in the manufacturing line.

키워드