Study on stable delivery of charged uniform droplets for freeform fabrication of metal parts

Abstract

Electrostatic delivery of charged uniform metal droplets is a novel method to deposit metal parts with short process period and low cost. But the delivery process is unstable and delivery accuracy of charged droplets deteriorates because of actions of mutual interactions of closely charged droplets. A droplet generator with droplet charging and deflecting system has been established to find out the way for stably and accurately deflecting droplets. The parameters for generating uniform droplets were first studied. Then the droplet deflections and metal parts depositions with different charge methods were discussed. The results show that the unbalanced electrostatic repelling forces are the main factor to cause the unstable deflection of droplets. The droplets deflection distance can be predicted and controlled by balancing the repelling forces of charged droplets. The metal parts are stably deposited after combining the board charged pulse and substrate motion, indicating that the work can provide useful theoretical and experimental guide for droplet-based freeform fabrication. electrostatic delivery, uniform metal droplets, metal parts, freeform fabrication Citation: Luo J, Qi L H, Zhou J M, et al. Study on stable delivery of charged uniform droplets for freeform fabrication of metal parts.

Improved Continuous Inkjet for Selective Area Coating Using High‐Viscosity Insulating Inks

“…Jetting speed can also influence the breakup position and behaviors, which are important for the proper charging of individual droplets. [ 21,36–40 ]…”

Pattern Transformation of Heat-Shrinkable Polymer by Three-Dimensional (3D) Printing Technique

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“…However, fabrication of heat-shrinkable polymer with controllable microstructures still remains a significant challenge. With development of three-dimensional (3D) printing technique, polymer with complex microstructure can be easily fabricated 7 8 9 10 11 12 13 14 15 16 17 18 and the structure or microstructure of the printed sample can be achieved to deform under different stimuli by employing active printing materials such as shape memory polymer, called 4D printing 11 19 20 21 . However, internal stress/strain of the 4D-printed structures still need to be generated by applying external stimuli during programming step, not generated from processing step.…”

Printing solder droplets for micro devices packages using pneumatic drop-on-demand (DOD) technique

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“…4, the droplets generated in this case were collected in the oil. Luo et al (2011) showed the statistical result about 370 droplets diameters shows that the average diameter and the corresponding standard deviation are about 350 m and 9.4 m, respectively.…”