Last Update: 9:23am (ET) on April 7, 2020
There are three primary components to the U-M/PRUSA Modified design. They include the following: headband, shield foil and elastic strap. The current preferred design and materials for the DIY community are as follows:
|Design Files:||Current 3-hole model (modified PRUSA R1 design).
See “Design Details” section below for further information on model.
|* If using these materials ensure that you are following the appropriate ventilation specifications, outlined below in the “Safety Precautions”|
|Thickness:||Minimum of 4 mil (for Polyester) – 5 mil (for Mylar)|
The U-M approved design is a modified version of the Prusa RC2. It has the following modifications:
- Removal of the “Prusa” logo
- The original 4-hole visor mounting is altered to a 3 hole mounting pattern consistent with North American hole punches.
- The hexagons were removed because they caused print issues.
- The pegs now have a catch. One peg is rotated to catch the laminate from slipping sideways, the other two present the laminate from falling down.
- The band thickness is 0.5mm thinner and the height is 2mm less tall. This is to offset the increased stiffness from eliminating the hexagons.
- Elastic pegs are much smaller.
PLEASE DO NOT PARTICIPATE IN THE PRODUCTION OF FACE SHIELDS IF YOU ARE DISPLAYING ANY SYMPTOMS OF COVID-19
- Take your shield and line up the holes at the top of the shield with the 3 pegs of the headband. (If you have a sheet that doesn’t have holes, please use a standard 3-hole cutter to punch holes along the top part of the shield that is ~11”. No additional adhesive should be necessary.)
Specific Production Notes/Requirements
U-M EHS Makerspace Guideline recommends the following ventilation considerations for 3D printers.
- 3D printers using PLA or PETG filament can be operated in a lab space without special ventilation considerations as long as the general ventilation equates to at least 4 ACH (air changes per hour), and only one printer is in use. If more than one printer is in use, EHS should be contacted to evaluate the need for increased ventilation.
- 3D printers utilizing ABS filament shall be ventilated using any of the following:
- A compatible attached ventilation system (filtered or direct exhausted)
- An EHS-approved fume extraction local exhaust ventilation system (LEV) (filtered or direct exhausted – LEV)
- A fume hood
- Single-pass general ventilation and no less than 6 ACH
For U-M faculty/staff/students with 3D printers in campus shops or laboratories, this activity may be considered as “Directly related to COVID-19 and have a timeline for deployment that could address the current pandemic” in accordance with UMOR COVID-19 Research Operations Protocols. Shop or laboratory directors should request access to facilities with resources to support this activity using procedures applicable to your School or College, or by contacting the office of your Research Associate Dean.
For U-M faculty/staff/students with 3D printers at home, it is highly suggested that they are used in well ventilated areas. For specific recommendations please consult Section 8: Exposure Controls/Personal Protection of the Safety Data Sheets (SDS) for the filament materials being used. Users should consider returning any U-M equipment taken home to a campus shop or laboratory in accordance with the campus shops or laboratories section above.
Print Settings: 0.2 mm thick layers, 3 line wall count, & 20% infill (though these may be slightly different for your own machine)
Cleaning Standard: Current desire is for shield material to be tolerant to cleaning via Oxivir (wipes). No current cleaning standard provided for spray or soak.
Please mark both the headband AND shield foil with the type of material used, e.g., “PLA” on a 3D printed PLA headband, “Polyester” on a polyester shield foil, “Mylar” on a Mylar shield foil. Silver sharpie seems to work well on a variety of surfaces and colors.
Please note that any unmarked headbands or shield foil may be limited to single use due to uncertain compatibility with disinfecting methods.
Questions please contact: firstname.lastname@example.org
Drop Off Details
PLEASE DO NOT DISSEMINATE DIRECTLY TO HOSPITAL OR HEALTH CARE WORKERS TO AVOID INADVERTENT CONTAMINATION.
Please drop off all ASSEMBLED homemade face shields at the Michigan Medicine drop-off donation site, located at 2800 Plymouth Road, Ann Arbor, MI 48109