Evaluation of ultrasonic cleaning process

Abstract

Purpose. To establish relationship between intensity of ultrasonic cleaning and an ultrasonic response fixed at a set point. To determine the influence of liquid contamination on this signal. To specify parameters of an ultrasonic signal to evaluate the course of cleaning a preset section of a body. To define limiting values indicating efficiency of ceasing the cleaning process. Methodology. The research is based on simulation of ultrasonic wave propagation in the heterogeneous environment and subsequent analysis of the signals by using software. Findings. Dependences are established to form evaluation of the course of the cleaning process by parameters of the ultrasonic response. It is found that both the bodys state and that of the liquid affect the ultrasonic response obtained by the sensor at the set point during ultrasonic cleaning. With high contamination (>30%) the state of the liquid becomes a critical factor for forming the signal of the ultrasonic response. With that, there is an abrupt reduction of threshold signal arrival time and increase in the main amplitude, which is to be one of indicators of ceasing the cleaning process in case of its inefficiency. With lower contamination, suspended contaminant particles only correct the signal to some extent without distorting it. There is a relationship between reduction of contamination, the arrival time of threshold signal, on the one hand, and the value of the main amplitude and the 2nd and 3rd-order nonlinearity coefficients, on the other hand. The arrival of the threshold value of the signal is the major parameter determining intensity of cleaning, i.e. reduction of contaminant thickness, which is determined by the value of the main amplitude of the signal and the 2nd and 3rd-order nonlinearity coefficients. Originality. For the first time, methods for evaluating the course of the ultrasonic cleaning process by analyzing ultrasonic responses at a specified point have been developed. Practical value. To consider spatial distribution of the ultrasonic cleaning process, its control is to be based on evaluating the bodys contamination in several preset points. To implement this, the character of dependences between changes in contamination of the body section and parameters of the fixed ultrasonic response is determined. Impacts are considered of suspended contaminant particles in the liquid on the signal analyzed. The observed relationship will provide the basis for building the spatially distributed control over ultrasonic cleaning considering the cleaned bodys state.