Precision Dispensing Screw Pump Glue Flow Pattern Study

The IC packaging technology and the relevant equipments are rapidly developing with the development of microelectronics technology. The dispensing technology is widely using today for it is key equipment in IC packaging. There are several types of dispensing: time-pressure, Archimedes pump, piston pump and jetting. The Archimedes pump is used more and more widely because it features many advantages which include strong adaptability for it can dispense kinds of fluid, and the ability to produce different size of dot, and the ability to make pattern. The Archimedes screw is highly appreciated by engineer, and the principle research becomes emergent and important.The advantages and application of Archimedes pump is described in this article. The fluid dispensing theory of Archimedes screw is developed by theory analysis, numerical simulation and experiment. In this article, Fluid flow is divided into three sectors—transferring, screw, needle. The fluid rate equation in the screw is derived from Navier-Storks equation. But the equation can not predict the whole flow, numerical simulation is necessary. The 3D model is built in Pro/Engineer and meshed under GAMBIT. The simulation is finished in FLUENT. The sliding grid technology and Non-Newtonian power low model are used in the simulation. Experiment is achieved which proved the simulation.The conclusions gotten from the simulation and experiment are: the angular speed is a key factor to effect the dispensing; the flow rate of fluid is decreased exponentially when the needle size gets small, But when the size of needle gets large to extent the rate will not continue to increase. In the parameters of screw, the depth has stronger affection to flow rate than the width, and although the area of cross get larger by increasing the depth of screw, the flow rate become smaller. The standoff has a key effect to the consistency of dots. Archimedes screw design and control system are given in the last of the article, which provide reference for the designer.