Papers by Keyword: Droplet Generation

Abstract: nkjet printing has proven to be a promising and flexible process methodology for low cost and drop-on-demand pattern formation in small-scale devices with a functional material. In this paper, micro droplet deposition using 80 micron diameter nozzle with micro piezoelectric printhead was investigated using a mixture of three fluids, distilled water (DW) and solutions of two different percentage of glycerine (G) as an operating fluids. The droplet formation capability and stability was studied according to the influence of pulse amplitude, dwell time and fluid viscosity. The results show that the optimal drop velocity to obtain a stable printing range from 0.5 ~1.5 ms^-1 which corresponds to pulse amplitude range of 25 to 100V and dwell time 15 to 35 μs. Respectively droplet formation and dispensing performance give benefit in dispensing application and build a solid background to inkjeting functional polymer material.

Abstract: We employ numerical simulations to investigate the breakup of droplets in micro-and nanoscale T junctions which are used to produce small droplets from a large droplet. A Volume Of Fluid (VOF) method was used and for verifying the accuracy of simulation the results compared with two analytical researches. Our results reveal that breakup time and breakup length of the droplets play important roles in handling these systems optimally. Our results also indicate that for nanoscale T-junctions by increasing the capillary number the performance increases while for the micro-scale systems there is a specific capillary number for which the system is in its optimum condition.

Abstract: To reveal the jetting of fine drops, model of 2-phase flow between gas and liquid is offered based on volume of fluid method. Numerical simulation is launched for the droplet generation through narrow nozzle, and key factors are discussed. Aiming at the ink marking of defective dies in IC production, a jetting inker driven by piezoceramic stacks is developed. The actuation properties are derived; waveform of induced pressure at nozzle entrance is estimated, which coincides the numerical results. Performance of ink dot jetting is evaluated and simulation results are verified.

Abstract: Ink marking is a key process for die sorting of IC wafer manufacturing. Intensive production of wafer is urging the inkers for more rapid and more stable ink marking performance on surface of defective wafer dies safely. In this paper, a non-contact jetting dispenser is introduced to the wafer die marking. After presenting the mathematical description of dynamic fluid for 2-phase flow, numerical simulations are launched to reveal the characteristics of droplet generation and key factors are discussed. A jetting dispenser is developed and experimental results are analyzed. According to the simulative results and the dotting performance shown in experiments, the non-contact jetting dispenser is capable for wafer die marking in dotting efficiency and stability.