Investigation of the factors to improve the accuracy of the inspection system for loosening screws using ultrasonic vibration

Various inspection methods for screws that are frequently used in assembling all products has been reported to prevent accidents due to loosening in advance. However, there is no accurate and simple method at present. As a solution to this, previous research has developed an inspection system that combines mechanical impedance spectra and spectral pattern recognition. Following the research, studies on suppressing variation in measured values, reducing measurement time, and measuring small diameter screws have been advanced. As a subsequent study, we examined the effects of variation in the pressing load on small diameter screws, evaluated the contact position dependence between screws and probe, and investigated the effects of several different types of screws. Through these investigations, we aimed to realize an inspection system with highly accurate performance.