FAB-ES
Fabricatable (E)lectro(S)pinning Machines
for
DIY Filter Media Production
by Filippos Tourlomousis, Jiri Zemanek and Zach Fredin
The Center for Bits and Atoms, MIT
A. Filters: Design Specs
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B. Process: Electrospinning
The Electrospinning process is based on the electrohydrodynamics phenomenon, where a material substrate loaded within a syringe with a charged needle tip attached to it and pointing towards a grounded collector, is extruded and subsequenlly stretched using a high volatage potential. Assuming that the material substrate is viscoelastic enoough and as soon as the electrostatic stresses overcome the surface tension of the material, fibers in a chaotic motion are deposited on the collector. The fiber formation mechanism is shown in the video below:
The two main types of electrospinning process are: a) solution electrospinning (SES) and b) melt electrospinning (MES). This classification is based on the material form used for processing; with SES using a polymer solution (pellets/powder mixed with solvent) and MES using pure polymer melt without any chemical solvents. The 3 main common system components for both process types are: a) the extrusion device that can be either mechanical using a syringe pump or pneumatic, b) a high-voltage power supply and c) a collector that in the most basic setup is a flat grounded aluminum plate.
Different types of nozzles and collectors assembled either in a horizontal or vertical configuarations have been reported in the literature leading to different types of electrospinning processes. Each electrospinning process has advantages and disadvantages depending on the application.
C. What is the best type of electrospinning process for rapid diy breathing filter media production?
- high-throughput
- multiple nozzles
- rolling collector
- polymer solution for functionalization
- hydrophobicity
- anti-viral material
- fast cheap assembly
Below in Section "D" we propose 3 different types of electrospinning machines of varying complexity and capabilities staring from the simplest one that can be made with off-the0shelf components that might be laying around in a hospital, moving to a simple design that reducing the cost, is parallelizable and can be made in a fab lab using a laser cutter and a 3D printer and resulting to a slightly more advanced for increaed throughput.
D. FAB-ES Machine Collection
Designs with increasing complexity/capabilities
FAB-ES Machine #1
The simplest ES machine made using mostly off-the-shelf parts found in a hospital
Parts:
Tools:
