High-resolution Fused Deposition 3D Printing Based On Electric-field-driven Jetting

In order to solve the problems of the limitations and disadvantages in printing resolution,printable materials,substrate flatness,etc in the fused jet deposition,a new technology of electric-field-driven fused jet deposition 3D printing was proposed.A dual-heated integrated nozzle at which applies a single positive pulse high voltage(single potential)connected with the self-aligning effect were used to eject and precisely deposit a small amount of molten material to form a high resolution structure.Based on the proposed electric-field-driven fused jet deposition high-resolution 3D printing technology,this thesis investigated the theoretical modeling,the simulation of the electric field distribution of jet and the self-alignment effect,the development of high resolution electric-field-driven fused jet deposition 3D printer,to explore the influence of process parameters and to print several typical engineering structures.The main researches and the innovations are as follows:(1)A new electric field generation method has been proposed.The nozzle was connected to the high voltage while the ground electrode is cancelled.Thus,the charges on the surface of the printed substrate were induced to realign due to the electrostatic induction and finally form the jet electric field between the printing substrate and the nozzle.The varieties of the substrate materials and the printed material are expaned due to the way that form the electric field,as a result,the applied range of this technology has been greatly expanded.(2)According to different printing materials(different materials have different surface tension),two different printing modes,the pulse cone jet mode and continuous cone jet mode,are proposed to realize the drop-on-demand(dot pattern)printing and the continuous printing of micro-filaments with a high efficiency.(3)A simulation of high-resolution electric-field-driven fused jet deposition 3D printing was established,and the electric field distribution and temperature field distribution simulation were obtained.On the one hand,the simulation results show the electric field strength around the nozzle and the printed substrate,revealing the direction of the force of the droplet in the electric field.On the other hand,it shows the temperature distribution in the dual-heat integrated nozzle,and the heating trend of the printed material is obtained.The theoretical analyses ensure the feasibility and innovation of the technology.(4)The self-aligning effect is proposed,and the correctness of the self-aligning effect of the technology is verified by simulation and comparison experiments.During printing,the jetting filaments are biased towards the printing entity closest to the nozzle to complete high-precision,high-aspect ratio printing due to the self-aligning effect that can compensate for the slight offset of the nozzle during printing.(5)Aiming at the technical characteristics of electric-field-driven fused jet deposition high-resolution 3D printing,a new set of 3D printers was designed and developed for high-resolution three-dimensional manufacturing of molten materials.The print head heating mechanism includes nozzle heating and barrel heating,which is more conducive to the original performance of the printing material,and more stable and reliable to the printing process.(6)Through systematical experiments,the process parameters are optimized,and the influence rules of process parameters on the printing process are obtained.Finally,the micro-scale structure for different application fields are completed using the technology.Typical cases are as follows:Large-size micro-scale mold with a minimum line width of 4?m and an overall size of 80 mm 80mm,large aspect ratio microstructure with a maximum aspect ratio of 25:1,microscale grid three-dimensional structure such as biological scaffold and single cell culture plate,liquid microlens mold and micro-droplet paraffin pattern.