The Device Design And Technology Research For The Liquid Metal Droplet Formation

Liquid metal(Ga-In alloy)is currently used as a conductor material for flexible electronic packaging which has become an important conductor material in the preparation of new flexible conductors,and it is liquid at room temperature.Morever,it has good technological conformability,high conductivity and nontoxic.The main current methods of preparing flexible liquid metal wire mainly include simple tool direct writing,printer printing and injection pump extrusion,where there exists a problem of accuracy and stability to some extent,which may easily result in the unevenness of the size for flexible wire products.Therefore,a method of preparing micro droplets by electromagnetic on-demand was proposed in this paper,and the preparation process of micro droplets was studied as well,which would serve as a basic exploration for the 3D printing of the flexible wire.The main contents of this paper are as follows:On the basis of the establishment of a physical model,the feasibility of the electromagnetic driving micro jet process was analyzed.The conditions for realizing micro injection could be obtained by some theoretical calculations.The design of electromagnetic driving droplet injection system was carried out on this above mentioned basis,and the suitable magnetic field source and current source were selected as well.The driving cavity and auxiliary device were designed,and the electromagnetic driven droplet ejection device was successfully built in the end.Through the high-speed photography technology,the whole process of the micro injection process was traced,and the influence of the electrical parameters of the injection process on the droplet formation process was also analyzed.Based on the electromagnetic driving droplet preparation device,where the magnetic field strength was 0.63 T,the maximum current amplitude could reach up to 40 A,and the nozzle aperture was 448?m,the influence of control parameters such as driving waveform,current amplitude and frequency,and pulse width on the micro injection process was studied.It could be concluded that only if the driving waveform was set as a pulse wave,the one-to-one correspondence between the micro injection frequency and the input frequency could be achieved.The theoretical model between the current amplitude and the limit frequency of the micro injection process were established,and the proportional relation between the amplitude of the input pulse current and the limit frequency of the micro injection was explained.The influence of the parameters(pulse frequency and current amplitude)on the average diameter and droplet mean velocity of micro droplets during micro injection process were analyzed.The results showed that the frequency of input pulse was inversely proportional to the average diameter of droplets as well as the average velocity of droplets,and the input current amplitude was proportional to the average diameter as well as and average speedof the microdrops.