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Material extrusion systems such as LLNL’s Direct Ink Write (DIW) systems do not have the ability to start and stop ink from flowing without passive flow (leakage) from the printer nozzle.  This is a significant disadvantage since it prevents complex geometries from being fabricated;   limiting the printing of objects which have geometries that are continuous (i.e., toolpaths that are analogous to a pencil never leaving a paper when drawing).  Turning flow “on” and “off” deviates the process from steady state and would require modification to upstream hardware of the nozzle.


LLNL researchers’ approach to this challenge is to design a modular valve subsystem that redirects the flow away from the main nozzle to an “exhaust”. By re-routing the flow to a different exit port, steady state flow can be better maintained.  The re-routing requires actuators that work in tandem; open and close of the nozzle and exhaust valves have to be executed simultaneously.  The subsystem includes valve bodies, calibration process, sensors/actuators, and a local network computer controlling the process. There are many variants of this design, which are described in the patent application.

  • Value Proposition:  Material extrusion flow control system ideal for complex geometries.
  • Reduced transient flow and leakage
  • Adaptable to other applications besides 3D printing
Potential Applications
  • Direct Ink Write (DIW) and other Material Extrusion 3D printers
  • Embedded Vat Printing
  • Big Are Additive Manufacturing (BAAM)
  • Concrete or other construction material extrusion printing
  • Bioprinting
  • Fused Filament Fabrication
Development Status

Current stage of technology development:  TRL 3

LLNL has filed for patent protection on this invention.

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