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New Mexico State University
Department of Physics
Boris Kiefer, Professor

Welcome

  • Education and Professional Experience
  • Research: Computational Materials Science
  • Research: Additive Manufacturing
  • Disclaimer 1: The following statements reflect my opinion, independent of the institution.
    Discaleimer 2: The correct course of action is to first inquire with the manufacturer about availibility part. There are very good reasons why medical devices need to be approved before using.


    According to a recent interview with NIH director Francis Collins the spread of COVID-19 in the U.S. is on an exponential curve and indicates that the U.S. may only be eight days behind Italy. If this estimated lag time is even close to be correct, we will need to think outside the box and look for strategies that better prepare nations for the COVID-19 pandemic on a very short timescale. Question: Can 3D printing technology mediate shortages in essential supply lines caused by the COVID-19 pandemic? An excellent example for thinking outside the box comes from a hospital in Italy. Here, 3D printing was used to print and fight the ventilator. Consider: if the target is to manufacture 100,000 valves per day, and we assume that it takes ONE HOUR to print a functioning valve, and we are willing to print FIVE valves per day, it would take 20,000 3D printers. Given that there are estimated to be over SIX MILLION 3D printers in the world, this should not be impossible. What is missing? Opensource stl files for the needed parts, and some information as to what filaments not to use. One might object to these numbers, but the main message remains: distributed 3D printing in-home manufacturing resources could have a high potential for relieving manufacturing shortages due to the COVID-19 pandemic. What are other parts that may be 3D printed in-home? I am not a health expert, but would it be possible to 3D print a "ventilator splitter" that allows to put two or more patients on the same support? The strategy of multi-patient ventilator support has been recently discussed in this piece published on 03/15/2020 piece by Furkas.



    Are you 3D printing PPE and other medical parts that may save lifes? Here are some drop-off locations:
    Las Cruces: Cruces Creatives; 205 E Lohman Ave Las Cruces; NM 88005
      Instructions: drop-off in plastic bag; bulk drop-off is possible.
    Click here to the link to the stl file that Las Cruces Creatives recommends to 3D print. It is very similar in style to the 3DVerstan design shown further down on this page. In particular the spacing between the holes is the same. The only two differences are: 1) the padding is ~9mm wider than the 3DVerkstan verion (link to stl file in 3DVerkstan figure caption below), accommodating a face mask more easily; 2) it has a small lip for extra support against the forehead ==> if you have 3D printed 3DVerkstan holders, they can still be used. For updates on COVID-19 related projects see Cruces Creatives.
    Figure caption: Three left pictures: Las Cruces Creatives holder; holder with clipped in 2x3 holes punched overhead transparancy; and stack of pre-mounted face shields. Right: 3DVerkstan holder (narrower padding).
    Albuquerque: Materials Management; 2211 Lomas Blvd NE; Albuquerque, NM 87106
      Instructions: drop-off in plastic bag; bulk drop-off is possible.
      Dropped-off 50 frames and face shields.



    Figure caption: 3D printed Ear Savers. Headaches after wearing a facemask with straps behind your ears? The origin might be strain excerted by the strain on your ears. Here are a few Ear Savers that I found on Thingiverse. Top: hexagonal opening for ponytail...; middle: many adjustable options, small opening in the middle; Bottom: fewer options simpler print. All prints take less than an hour.


    Figure caption: Design of ventilator splitters face several challenges: medical: they must be air tight; compatible with ventilator machines; individual pressure control; pressure loss after splitting,... Top row:First attempt at 3D printing a splitter with pressure control (design: Galen Helms; NMSU Physics). The right picture shows that it is stackable to other ventilator splitters, and a venturi valve that may increase the dynamical pressure after splitting. Controlling the pressure in one outlet is likely sufficient since the total pressure can be controlled at the ventilator machine itself. Similarily, with or without pressure control it is easier to find to COVID-19 patients with similar pressure requirements, as compared to four patients. Therefore, I think it is easier to work with a two-way splitter. Middle row: Here is my first attempt in printing a ventilator splitter. The stl file for the 4-way splitter was obtained from the PRUSA webpage. Nozzle temperature 220C; bed 60C. The picture shows a tear in the printed part, and a little bit of rougher print on the leaning parts of the splitter. Keeping everything the same and only changing the PLA shows drastic changes in the permeability of the walls. As a simple test, I filled the splitter with water closed the openings and blew into one as hard as I could: for one PLA filament water droplets formed on the outside, while the other PLA filament showed no sign of water leakage. More than anything these are concept printis, it is meant to gain experience in printing more complicated pieces and to have the necessary expertise when parts like this splitter may be needed to safe lives. WARNING: THIS SPLITTER HAS NOT BEEN VERIFIED WITH ANY HOSPITAL OR MEDICAL CENTER TO THE BEST OF MY KNOWLEDGE. Also shown (right) is a different splitter, (link to stl file) it is stackable with the first one, but has 4 vertical shells instead of 2. It passed the first test no water leakeage even after blowing in. This seems to suggest that 4 vertical layers may be sufficient to build a ventilator splitter. Also tearing no longer occured. Bottom row A ventilator splitter with thicker walls that reduce permeability/leakage the stl file was obtained from http://ventsplitter.org/. The thicker wall ventilator splitter (light blue) passed the water test described above. Moreover, different splitters can be stacked as needed.


    Figure caption (face shield; 3DVerkstan): This face shield holder was designed for simplicity and 3D print speed. The stl files are freely available and the face shield has been tested at Cornell University hospital. The way it works: make 2x3 holes with a regular 3-hole puncher using the spacer for positioning and attach to the holder. I assume that low gloss overhead transparancies may be used or any other flexible/light transpatent plastic. I printed the holder in ~90 minutes, on my in-home 3D printer, the 3D print worked on fist attempt, nozzle temperature 220C; bed 60C, ~15 m of filament, and the cost is ~35 cents; ~5 m of filament; the space used 0.5 m of filament and cost 13 cents. With a standard 1-kg spool of 1.75-mm PLA (330 m) should give 66 face shield holders. This should work on any 3D printer using the standard PLA settings you are used to. This afce shield currently validated in a collaboration between Las Cruces Creatives and Memorial Hospital in Las Cruces. When you print the spacer, test it to make sure it fits. When I tried it was off by ~0.25". Also shown is a stack of 10 face shield holders, this worked well but was a little slow and I need to change the print settings, to print a holder in 20 minutes. I obtained a stacked stl file for the holder from thingiverse.


    Figure caption: 3D printed face shield support. The stl file was provided by PRUSA and is available at Face Shield + holder. The holder was printed with PLA, on my in-home PRUSA MK3 3D printer. The nozzle temperature was 225C and bed temperature was 60C. I printed at 80% of the nominal speed and applied some glue stick for better adhesion od the part to the heat bed. With these parameters, the print took 7 hours (at 100% speed it would have been 5 hours), used ~14.6 m of filament and estimated cost is ~1.1 dollars. The stl file for the bottom support was obtained from the same location as the headband, 3D printed with the same parameters and took ~40 minutes, used ~1.8 m of filament and cost ~13 cents; from a 1 kg spool of 1.75-mm PLA one may be able to print ~22 face shields. This prototype has passed two verifications by the Czech Ministry of Health. At the time of this writing PRUSA has 3D printed over 12,000 face shields, showing the scalibility of this technology to protect and safe medical professionals in the fight of the COVID-19 pandemic.


    Figure caption: The stl file for this Venturi valve was provided by Filip Kober. The print settings are the same as before, filament length is 7.8 m, the associated cost is ~10 cents, and the print time was ~5 hrs. I was worried about the infill in the small nozzle to the sice and partially successful but than it broke off. However, that is when I realized that this may not be necessary due to the openness of the support in the nozzle. The pictures above are taken from the second print. I ran water through the small nozzle and it bubbles out in the opening in the center of the Venturi valve.

    These examples shows that distributed in-home 3D printing of sufficiently complex parts is clearly feasible, affordable, and can be accomplished on a timescale that is relevant to fight the COVID-19 pandemic.



    • Custom Filaments.
    • In-situ 3D Print Verification.
    • Other Applications of 3D Printing Technology.

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