Simulation Analysis Of Droplet Jetting Process And Development Of Jetting Molding Device

Droplet jetting additive manufacturing technology is a new kind of rapid prototyping technology which is developed in recently years. It has been widely used in biomedicine,microstructure manufacturing, microelectronics and so on for a wide range of molding materials, low energy consumption, low cost and high molding accuracy.The droplet jetting molding devices which are set up at present and provided pressure with gas used to be unstable, and that results in the inferior performance of the whole device.The mechanism of the droplet breaking on the jetting process and the factors affecting the droplet pattern are seldom studied.Therefore, this paper develops a droplet jetting molding device supplied pressure and liquid with jetting materials on the basis of the simulation analysis of droplet jetting process.Droplet jetting process is analyzed simulationally. To begin with, this paper presents the type of the droplet jetting, the instability theory of jet, and the mechanism of jet breakup. In addition, the droplet jetting process is simulated under the effect of the pulse signal using the VOF model of two-phase flow in the software of FLUENT, and the flow field, velocity field, airflow field, and pressure field in the droplet breakup process are analyzed in-depth aiming at revealing the microscopic change rules of the internal and external droplets in the droplet breakup process and this paper illustrates the reasons of these changes. At last, factors affecting the droplet pattern in the droplet falling process are analyzed simulationally, and influences that physical property parameters of the jetting liquid and the jetting process parameters have on the droplet diameter and the distance from the nozzle to the substrate when the droplet forms a round ball are studied.The simulation results show that there are five stages of the droplet pattern on the jetting process, namely elongating, necking, breaking, vibrating and balling; and the internalvelocity and pressure of the droplets are adjusting continuously on the droplet jetting process; and physical property parameters of the jetting liquid material have little effect on the droplet pattern, and the jetting process parameters remarkably affect on the droplet pattern.A droplet jetting molding device whose pressure and liquid is furnished with jetting materials is developed. A variety of nozzles are finished perfectly, and this article designs and achieves three kinds of pressure systems provided pressure with liquid. A more comprehensive droplet jetting molding device is developed after several improvements. Last and foremost, the simulation conclusions made in this paper are verified on the exploited device by experiments, and the experiment results agree well with the simulation conclusions. The exploited droplet jetting molding device runs stably,and realizes the droplet jetting successfully. This paper has a certain practical significance for the development, the popularity, and the application of droplet jetting additive manufacturing technology.