Simulation and experimental study on temperature field of fluid jet-dispenser
Fluid jet-dispensing technology has been widely used in micro-electronic encapsulation industry. The fluid viscosity varies as temperature changes, while it affects the process remarkably. Besides basic method on temperature field solution, some thermal behaviors, including heat conduction and heat exchange, boundary conditions and some physical parameters are overall analyzed in this paper. Based on the simulation software platform ANSYS, a two-dimensional transient temperature field model of jet-dispenser was built, and simulation programs on temperature field for two sorts of fluid with obviously different thermal conductivity were performed. Then heating experiments were finished to validate the feasibility of FEA, and results show that temperature distribution is homogeneous along fluid area and it meets the conditions of jetting.
Fluid dynamics of jetting dispensing process based on simulation and experiment
Dispensing technology is widely applied in semiconductor packaging surface mounting technology, LED packaging, where needs accurate flow control. Jetting dispensing with high performance is the mainstream in dispensing technology in the future. In this paper, FLUENT software is introduced to simulate the formation process of the droplets with a two-dimensional axisymmetric swirl model. The data of pressure distribution in the interior of the dispenser under certain condition could be get during the process, then a jetting dispenser driven by mechanical collision with experiment test system is built based on simulation results to study the process of jetting dispensing. Using a High Speed Digital-Cram, the image of the glue droplets formation process in the high speed jetting dispensing could be obtained and the volume of droplets could be analyzed with Image Processing Technology. Finally, the actual volume of the glue droplets calculated by a precision measuring cylinder are compared with simulation results and the test results show that the experimental results closely match the theoretical simulation. Under the condition of normal temperature, the jetting dispenser could realize the viscosity of glue up to 1.2 Pa.s, and the volume of droplet for 86nL.
Numerical Simulation of Cumulative Fluid Volume and Mean Flow Velocity of Jetting Dispensing
The fluid volume and mean flow velocity accumulating at the outlet of the jet-dispenser have great influence on drop formation and its characteristic,meanwhile the continuous changing resulted by fluid flow at the outlet of the jet-dispenser which changing follow the time.The calculation formula of cumulative fluid volume and mean flow velocity were deduced through central velocity at the nozzle outlet from the numerical simulation result,then cumulative fluid volume and mean flow velocity were computed under certain conditions of jet-dispenser parameters by MATLAB program.