Study And Application Of Ultrasonic Cleaning In Remanufacturing

As the extension of the equipment manufacturing industry chain, remanufacturing, which provides the critical technical support for circular economy, has become one of the most promising technology field in the world today. The cleaning technology of remanufacturing parts, nondestructive testing and life prediction technology of manufacturing rough pieces and components defect repairing technology are the three main factors that restrict the development of the remanufacturing industry. Due to its fast cleaning speed, good cleaning quality, low cost and easy to realize the advantages of automation, ultrasonic cleaning gets more and more extensive application in remanufacturing industry. Analysis of ultrasonic field is such an important content in ultrasonic cleaning scientific research and engineering application that it has an important theoretical guiding significance to master ultrasound field characteristics on the design of efficient ultrasonic cleaning equipment.Ultrasonic cleaning is a way of cleaning method combined with physical and chemical effects. Its physical mechanism summed up with ultrasonic cavitation and shock wave, micro-airflow, micro jet that generated after cavitation, and mechanical effect of cleaning fluid vibration itself. Chemical effect performances in chemicals of cleaning fluid generate an osmotic and lyses in the dirt. Through a numerical simulation and physical field coupling calculation of the equations of cavitation bubble motion, a better technology conditions to improve cavitation effect in theory was obtained, i.e. At the lower ultrasonic frequency, stronger ultrasonic power, lower viscosity, lower ambient pressure, and bubble diameter size for resonance, the cavitation effect was more obvious and the cleaning effect is better. The results of numerical simulation showed that the ultrasonic power, air pressure and bubble diameter made much influence on the cavitation bubble motion. The appropriate cleaning process parameters could be selected according to the specific work in practical application. In addition, as a method of mechanical motion, vibration also played a very important role in ultrasonic cleaning.The two-dimensional and three-dimensional model of ultrasonic cleaning were built in COMSOL Multiphysics and their cleaning effects under different frequencies were respectively simulated, from which the frequencies of cleaning machine suitable for remanufactured engine components were determined. The triangle asymmetric distribution of oscillators was determined through characteristic frequency analysis and three-dimensional acoustic pressure level analysis, through reducing the scope of standing wave and increasing the number of the working plane, the uniformity of acoustic field distribution was improved further. The liquid level height variation model was built and the calculation result showed that the liquid level height variation had a significant influence on the acoustic field distribution. Under the fixed ultrasonic cleaning equipment, working solution and temperature, the acoustic field distribution could be changed through changing the liquid level height, then the better cleaning effect could be achieved.The acoustic distribution of different working plane, the acoustic distribution along the axis and the distribution of different liquid level height are the key factor to limit ultrasonic cleaning effect, using Halcon and Matlab, the above problems were systematically studied through staining method, aluminum foil corrosion and hydrophone methods. Focusing on the standing wave field existed in cleaning tank under ordinary cleaning condition, the liquid level variation method was presented to achieve ultrasonic scanning cleaning. The experimental results showed that this method could change acoustic distribution in cleaning field obviously and the energy in cleaning field was redistributed, and through multiple distributions the acoustic field energy became uniform, so the uniform cleaning could be achieved.