| Ultrasonic precision sealing technology is a kind of packaging technology that is clean and efficient,and can be directly sealed without auxiliary agents.Therefore,it has been introduced into the field of micro-nano assembly of polymethyl methacrylate(PMMA)micro-nano devices in recent years.The precision sealing technology is still difficult to meet the precision requirements of micro-nano assembly.Since the visual information of the hot-melt interface directly reflects the fusion state of the interface,the vibration information transmitted by the ultrasonic wave in the micro-device is also deeply related to the fusion state of the interface.In order to improve the control accuracy of the hot-melt interface of PMMA micro-nano devices in the process of ultrasonic sealing,real-time monitoring of the hot-melt interface in the process of ultrasonic precision sealing and real-time detection of the transmission of ultrasonic vibration characteristics during the sealing process are proposed.Online visual monitoring and high-frequency vibration detection method in ultrasonic precision sealing.In order to realize the real-time monitoring of the hot melt interface during the PMMA ultrasonic precision sealing process based on the visual sensor,a high-frequency dynamic force sensor is used to detect the ultrasonic vibration characteristics transmitted from the ultrasonic tool head to the dynamic force sensor sensing surface in real time.Based on the above detection methods,a PMMA ultrasonic precision sealing experimental platform integrating visual monitoring and ultrasonic vibration detection functions was developed.The experimental platform contains three major modules,which are a motion control module,an ultrasonic loading module and an independently designed integrated online monitoring function base.The module is constructed,and the transmission efficiency of the structural vibration force and the improvement of the sealing level are optimized according to the experimental and simulation results.Through the finite element method,the functional base is simulated and analyzed to ensure the rationality of the online monitoring of the functional base structure and to confirm the transmission status of the vibration propagation characteristics in the PMMA device during the ultrasonic sealing process.The finite element analysis is divided into three parts.Firstly,the harmonic response analysis is carried out on the base with integrated online monitoring function to confirm that the structure is still stable under ultrasonic loading.Secondly,the viscoelastic finite element model with thermal expansion is set on the base with integrated online monitoring function,and the temperature parameters of the hot melt layer are set.The contact force between the dynamic force sensor and the base in the simulation model is set as the output,the vibration transfer curve corresponding to the interfacetemperature is obtained with the hot melt layer temperature as the independent variable,and the variation law of the vibration transfer curve is analyzed in combination with the material mechanical properties of PMMA.Finally,according to the preliminary test and simulation results,the optimization design model of the vibration transmission structure is simulated for the vibration transmission efficiency.In-depth research on the operability of the online monitoring of the hot-melt interface and the high-frequency vibration online detection method in the PMMA ultrasonic sealing was carried out.The online hot-melt interface visual monitoring in the PMMA ultrasonic sealing process and the vibration during the ultrasonic precision sealing Propagation characteristic detection experiment,the results show that the design basically realizes the online detection function of the hot melt interface and ultrasonic propagation information in the PMMA ultrasonic sealing,which provides a new way for the ultrasonic sealing technology in the control method. |
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