Papers by Keyword: Droplet Velocity

Abstract: In the spray forming process, the atomizing quality is not very good under the low pressure. This article attempts to improve the quality of atomization through heating the gas. A mathematical model is built and calculated according to the existing knowledge, and then the influence of airflow temperature in the spray forming is theoretical calculated and analyzed. The experimental results show that the average grain size is 54μm when the gas is not heated; the average grain size is 39 μm which decreases by 27.7% than airflow unheated when the gas is heated to 150 °C. The calculation results show that when the gas is not heated, the first time atomization grain size is 201 μm, the second time atomization grain size is 15 μm, the total atomization time is 92 μs. And the velocity of atomization droplets is 80 m/s; when the airflow temperature is 150°C, the above results are 131 μm, 10 μm, 76 μs and 127 m/s respectively, the atomization quality has a certain improvement compared to the unheated condition. At the same time, the grain shape becomes more round as the temperature of airflow increases, and the holes between the grains also become smaller.

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: As the dimensions of the structures of integrated circuits shrink, the influence of particles on device yield becomes increasingly important. According to the cleaning requirements of the International Technology Roadmap for Semiconductors (ITRS) in 2007, particles of 32 nm and larger are believed to be detrimental to devices and thus have to be removed. To remove nano-particles with minimal substrate loss and no damage requires very dilute chemistries and sufficiently gentle physical forces in a cleaning process. In this work the performance of an aerosol spray based cleaning technique is evaluated with regard to the removal efficiency of nano-particles as well as substrate loss and structural damage.