Lu Shizhou, Cao Guangyu, Zheng Hai, Li Dongqi, Shi Meiyan, Qi Jiahui
School of Mechanical, Electrical & Information Engineering, Shandong University at Weihai, Weihai 264209, China.
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China.
Micromachines (Basel). 2018 Jun 29;9(7):330. doi: 10.3390/mi9070330.
The needle-type droplet jetting dispenser has wide applications in the field of microelectronic packaging, and for which the good quality of droplet formation and separation is the key to successful dispensing. This paper simulates the droplet jetting process which has been divided into 5 stages named backflow, growth, droplet extension, breakage, and separation, and analyses the combined effects of system parameters, such as pressure, viscosity, needle stroke, and nozzle diameter, on the changes of morphologies of ejected droplets, which is verified by experiments. The simulation and experiment results show that a higher driving pressure is quite suitable for the high-viscosity liquid to form normal droplets by avoiding adhesion. When increasing the needle stroke, the pressure should also be lowered properly to prevent the flow-stream. Besides, the nozzle with a large diameter is much more likely to cause sputtering or satellite-droplet problems. The results have a great significance for guiding the parameter settings of the needle-type dispensing approach.
针式液滴喷射点胶机在微电子封装领域有着广泛的应用，而良好的液滴形成与分离质量是点胶成功的关键。本文模拟了液滴喷射过程，该过程分为回流、生长、液滴延伸、破碎和分离五个阶段，并分析了压力、粘度、针行程和喷嘴直径等系统参数对喷射液滴形态变化的综合影响，实验验证了该分析结果。模拟和实验结果表明，较高的驱动压力适合高粘度液体，可避免粘连从而形成正常液滴。增加针行程时，还应适当降低压力以防止液流。此外，大直径喷嘴更容易导致溅射或产生卫星液滴问题。这些结果对指导针式点胶方法的参数设置具有重要意义。
