In the paper detailing this new technology, the authors explained that they created the electrostatic jet deflection 

method to overcome the limitations of existing rapid  prototyping  manufacturing technology in terms of production 

speed. From their tests, the researchers found that the  electrostatic jet deflection method can achieve 3D printing of 

objects with sub-micron features by stacking nanofibers at a layer-by-layer frequency of up to 2000 Hz.

      The  achieved  jetting  speed  and  layer-by-layer  frequency are equivalent to a printing speed of up to 0.5 m per 

second in the planar direction and a  printing speed  of  0.4 mm per  second in the vertical direction. The researchers 

say this is "faster than the same precision feature size technology" Three to four orders of magnitude".

                                                            △Schematic diagram of 3D printed wall

                                                                  Improve 3D printing process

  The researchers first described the benefits of rapid prototyping manufacturing technology for today’s production, 

and wrote:  "Rapid prototyping manufacturing has become a new paradigm for distributed production of customized 

products,  in terms of geometric freedom of design,  material utilization, and shortened delivery. It has advantages in 

terms of period."

     Nevertheless,  the existing 3D  printing  process  still  has  many  researches  that  can be  improved.  For example, 

researchers   in  Austria  have  explored  the  need  for  necessary  improvements  in  material  extrusion-based  rapid 

prototyping manufacturing methods (ME-AM/FDM/FFF) to "meet the challenges of complex industrial applications." 

Other research  focuses  on  the  effect  of  fast printing speed in the binder jet process, especially in terms of surface 

roughness and density uniformity.

     Like  many  research  papers  aiming to improve the existing rapid prototyping manufacturing process, the author 

stated  that  there  are  some  limitations  surrounding the current 3D printing technology, namely production speed, 

material availability and combination, and control of the microstructure of the material. Realize function control. 

     "In addition,"  the author  added,  "For true distributed  production,  the  cost  and  complexity  of  manufacturing 

equipment capable of producing sub-micron features are prohibitive."

       △ac Schematic diagram of experimental PEO-PEDOT:PSS pattern (above) and optical photo of experimental PEO-

PEDOT: PSS pattern   (below):  a fiber bending  obtained  without  jet deflection;  b on a mechanical  platform Use the 

sawtooth pattern obtained by 1D jet deflection on the axis of translation; c use the circular pattern obtained by 2D jet 

deflection.  d, e Use  two  jet  deflection  electrodes  to  define  the  pattern  and  the  mechanical  stage to switch the 

substrate  between  printing events.  The  mechanical  stage to switch the substrate,  prints an  optical  photo of more 

complex 2D patterns. These patterns were printed using 4.7wt% PEO ink containing Ag NPs. Scale bars (D, E): 1 mm.

      In particular, nozzle-based 3D printing technology provides a good example.  This process provides  "unparalleled 

versatility"  because  it  can  make  objects with different degrees of materials, from polymers, metals, ceramics, wood, 

Even different materials such as biological tissues. "This incomparable material versatility stems from the use of metal 

or polymer melts or solvent-based inks. The formulation can contain any ingredient in the form of ions, molecules, 

nanoparticles, and even living cells." The researchers explained.

      However,  the current nozzle-based 3D printing technology is relatively slow and the printing resolution is limited 

because  the width  of the  printed  lines is related to the nozzle aperture, which is usually more than tens of microns. 

Even  if  a  smaller  nozzle  aperture  is  used,  frequent  clogging  and high viscosity loss are likely to occur during the 

printing process.

                                                  Using electrostatic jet deflection technology

      The  author  proposes  that  an electro-hydrodynamic  (EHD)  jetting strategy is unique compared to other nozzle-

based  3D  printing  methods.  In  2019,  researchers  at  ETH  Zurich demonstrated this. "EHD jet can print sub-micron 

structures  without  the  risk  of nozzle clogging, because it can use a variety of inks to produce nano-scale jets from a 

wide nozzle aperture, with a viscosity of more than several orders of magnitude."

                △Schematic diagram of 3D printed cylinder. The picture comes from Nature Communications.

However, the EHD jet technology has not yet been fully developed for wide applications, because the electrochemical 

jet is too fast and the mechanical  stage is relatively  slow to collect  materials  accurately.  "The current EHD jet-based 

system  uses a mechanical stage to position the printing material.  However, the mechanical stage can only match the 

huge speed of the electrochemical jet in a long straight line, but it cannot achieve this speed when printing small and 

complex patterns. Huge acceleration." The author added.

In  order  to  overcome  the  limitations  of  the  EHD  printing process, the researchers proposed to use electrodes to 

modify  the  electric  field.  Using  a traditional  EHD printer,  the researchers  placed the electrode around the jet and 

controlled the voltage  of  the  electrode  to  continuously  adjust its trajectory with a lateral acceleration of up to 106 

m/s.  This  allows  the  jet  to  achieve ultra-fast electrostatic deflection, allowing nanofibers to be stacked to print 3D 

objects with sub-micron features.

       From their tests, the researchers were able to 3D print objects with  materials  deposited layer by layer, up to 100 

microns in height, with a very high aspect ratio and high speed. Fast jetting and these high layer-by-layer frequencies 

translate into a printing speed of 0.5 m/s  in the plane and 0.4 mm/s  out of the plane, that is, in the vertical direction, 

compared to  extrusion  and  on-demand  dripping  EHD technology,  the same size is produced When characterizing, 

it’s three to four orders of magnitude faster.

      At the end of the paper, the researchers stated that the advantages of EHD jet deflection printing that they 

demonstrated in the paper may bring this technology closer to the ultra-fast and fast additive microfabrication 

of 3D objects.