Theoretical and Experimental Study on Vibration Propagation in PMMA Components in Ultrasonic Bonding Process

Abstract

Ultrasonic bonding has an increasing application in the micro assembly of polymeric micro-electro mechanical systems (MEMS) with high requirements for fusion precision. In the ultrasonic bonding process, the propagation of ultrasonic vibration in polymer components is related to the interfacial fusion, which can be used as a monitoring parameter to control ultrasonic energy. To study the vibration propagation in viscoelastic polymer components, finite element analysis on the bonding of poly methyl methacrylate (PMMA) micro connector to substrate for microfluidic system is carried out. Curves of propagated vibration amplitude corresponding to interfacial temperatures are obtained. The ultrasonic vibration propagated in PMMA components are measured through experiments. The theoretical and experimental results are contrasted to analyze the change mechanism of vibration propagation related to temperature. Based on the ultrasonic bonding process controlled by the feedback of vibration propagation, interfacial fusions at different vibration propagation states are obtained through experiments. Interfacial fusion behavior is contrasted to the propagated vibration amplitude in theoretical and experimental studies. The relation between vibration propagation and fusion degree is established with the proper parameter range for the obtained high quality bonding.

Ultrasonic bonding method controlled by the characteristic waveform of ultrasonic propagation

“…From about 14 s, it attenuates at fluctuate rates to about 1 N eventually. As discussed in literature [11], the variation trend is related to the mechanical property of interfacial polymer component. First, the increase is caused by the thermal expanding of polymer.…”

“…In the above‐reported methods, the energy is mostly controlled by ultrasonic loading time, pressure, power, or deformation. To improve the control accuracy of interfacial fusion bonding, the authors proposed the ultrasonic bonding method based on the ultrasonic propagation and studied the relationship between the propagated vibration and the interfacial fusion [10, 11]. The fusion degree could be controlled more precisely by this method.…”

Recent Advances in Thermoplastic Microfluidic Bonding

“…The variation tendency of vibration propagation was found to be steady, except for the peak-to-peak value of the dynamic force. The relation of ultrasonic propagation to the state of the thermoplastic was also observed [ 113 ].…”

Study on the Mechanism of Interfacial Friction Heating in Polymer Ultrasonic Plasticization Injection Molding Process

“…Ultrasonic vibration energy has been widely applied in the polymer micro parts molding process, such as ultrasonic patterning [1], ultrasonic welding [2], ultrasonic bonding [3], ultrasonic imprinting [4,5], and ultrasonic plasticization injection molding (UPIM) [6,7]. Under the action of ultrasonic vibration, the intermolecular force of the polymer to be processed is weakened, the activity of the chain is enhanced, and the degree of chain entanglement is reduced, meanwhile, it is continuously softened [8].…”