Experiments of adhesive distribution based on two-phase flow dispensing technology

This paper presented a novel approach based on the two-phase flow dynamics to dispense the liquid with a high consistency and accuracy. The new technology adopted the direct driving principle to induce the stable pattern of slug flow formation separating the bubble and droplet uniformly and individually in the micro-channel. In the experiments, the gas and liquid streams entered the mixing chamber in the same time with a flow rate of Q_gas=~300 ml/min and Q_liquid=1-3 ml/min. A gas-liquid two-phase flow had been formed stably in the mixing chamber to spray droplets out of the nozzle. The results revealed that decreasing the distance between the gas needle terminal and the nozzle orifice had increased the dispensing frequency and decreased the droplet mass, volume and diameter under the same parameters of gas flow rate, liquid flow rate, diameter of nozzle hole and diameter of gas needle. Increasing the liquid flow rate could increase the frequency of droplet dispensing. The lower mass of droplet was related to the higher frequency of droplet dispensing. The minimum volume, mass and diameter of droplet were 101 nl, 105 μg, 578 μm respectively with the frequency of 54.6 Hz.