Dr. Dave Martin, Professor of Biology and Randy Thoe, Instructor of Manufacturing and Machine Tool Technology, are the leads to a team at MJC that is creating and supplying NIH approved 3D PPE equipment to healthcare workers. #MJCSavingLives
There are many options for 3D printed PPE, but Dr. Martin and Instructor Thoe have been focusing on the designs that are NIH approved. There are really two products that they have been supplying health care providers to date: ear savers and face shields.
Dr. Martin writes:
The easiest one to explain is the ear saver as seen in photos 1 and 2. In the second photo I am wearing an N95 dust mask, which has an expiration port, with a surgical mask over the top to conserve the N95 as per NIH Guidelines for extending the use of the N95. Thus, the ear-loop surgical mask is stretched to capacity. As you can see, this ear saver is adjustable for different size heads. If the extra is bothersome to the user, it can easily be cut with bandage shears. These are very popular because having to wear a mask over your ears all day long really cuts up your ears.
We really have three options ready to go right now. All three face shield options use a front screen that is made from an acetate sheet, which is used for overhead projectors, that is punched with a standard 3-hole punch. The screens can be disinfected several times as per NIH guidelines (Sani-Cloth, 10% chlorine solution, CaviWipes or soap and water), or simply removed and replaced with a new sheet. The sheets are easy to obtain at office supply stores, and I now have several hundred that I am supplying with the shields to get them started. The visor part is printed with PLA plastic (a plant-based plastic that is nontoxic), and can be disinfected as per NIH guidelines until the plastic breaks down after a couple of months of continuous use. The visors are printed at 210 deg. C, so they are effectively sterile, but I wash them in a bleach solution and place them in bags before delivery. They should be disinfected again before use. In-hospital assembly requires placing micro-foam surgical tape on the brow piece for comfort and then using using either linked rubber bands or Coban (and elastic like bandage material) to anchor the shield to the head. The original design (the DtM 3.1) called for button hole elastic, but that is becoming hard to get and it must be disposed of after each use, so either rubber bands or Coban are better options, and I think the Coban is more comfortable anyway. The foam tape, Coban or rubber bands are removed and disposed of before subsequent disinfection.
The first shield is the NIH approved DtM 3.1 shield shown in photos 3 and 4. As you can see it has a top cap that provides protection over the top of the front screen, which would be important when performing certain procedures such as intubation. This shield is surprisingly light and relatively comfortable.
One note, this shield bill takes 12 hours each to print for the best finish and durability.
If I sacrifice surface finish and a little durability, I can get the print time down
to 3 hours each, which is a big advantage given the current crisis. Photo 5 is a close
up of the difference in surface finish between the normal and rapid print. The red-ish
print on the right is the rapid print.
The second face shield is the UCSF shield design. UCSF is using 300 of these per day, so the emphasis is on maximum production to meet their needs at this time. The UCSF shield has an open top design, which means particles could over-top the front screen during certain procedures, so it is NOT NIH approved, but it is being used at UCSF. See photos 6 & 7 of the UCSF visor and photo 8 compares DtM with UCSF. The biggest advantage to these is that they can be printed in as little at 30 minutes, and they can be stack printed, which means overnight printing is efficient, so greater production is possible.
The third option we have is the MJC shield design that is basically ready to go. It is a collaborative design we came up with here at MJC to solve problems with the other two designs. It is basically patterned after the UCSF visor with optimized geometry for printing. It has a flat filled bill (no top opening) and larger hooks over the ears to better accommodate Coban, but rubber bands can still be used. We also strengthened the stress points and rounded the corners and edges to improve the comfort when worn. This design should be fast-printing, about an hour and 20 minutes, and provide nearly the protection of the DtM visor with 1/2 the print time of the DtM and much greater protection than the UCSF visor. The MJC shield design can be seen in photo 8. We are also working on our optimized version with the addition of the bill cap that is very similar to the NIH-approved DtM."
At present I am having conversations with Doctors Hospital about supplying their needs, and I have ten face shields and like 30 ear savers I will be giving to Doctors Hospital staff tomorrow for testing. I'm giving them to a past student of mine who is now a nurse in the ICU. She is going to meet me near the SCC at 6 before she goes to work to keep me away from the hospital. If I get sick, I will have to stop making PPE, so it is better if I stay away from people and hospitals completely, and when I go out I wear gloves and a mask. It is like being on double lock down. It is CRAZY!
One other item we may be helping with is ventilator splitters. I have printed a few different designs files for review by the hospital just in case they are needed, but I don't want to print very many until I know exactly what the hospital wants. However, we also need to move forward with the splitters as soon as possible to get the parts ready for the surge should they be needed because the splitters will need to be very high quality prints, and thus time consuming prints.