VIBRATION ANALYSIS OF DISPLACEMENT MAGNIFICATION MECHANISM IN JETTING DISPENSER UNDER HIGH FREQUENCY WORKING CONDITION

The objective of this study is to analyze the vibration characteristics of displacement magnification mechanism of jetting dispenser, which is widely used for LED or flip-chip packaging process. This dispenser is driven by dual piezostack actuators with a hinge lever mechanism to precisely control the amount of dispensed high viscosity liquid and its working speed. The rod attached to the other side of lever works as a pump while it is moving up and down. The contact occurs between rod and dispensing nozzle and it may cause the deflection on the lever structure. The deflection of the lever during the dispensing process in high-frequency working condition leads to serious issues such as delays in actuating frequency from control input (activating) frequency. The delays between activating frequency of piezostack actuators and the rod motion due to such deflection lead to the inaccuracy of the amount of dispensed liquid. Therefore, the dynamic modeling of this dispensing system is configured, and dynamic analysis is carried out to examine the delays in working frequency and the amount of deflections. The working frequency of pump and deflections of the lever are examined under various working frequencies. Also, the mode shape of lever hinge mechanism is analyzed and the results are used to redesign the structure of lever hinge system to minimize the deflection.