RCBI at Marshall University

The Center for Innovation
COVID-19 Response: Model As Support System (MASS), 3DP of Medical PPE
Summary:

Included is a list of growing resources to an approach to scaled manufacture of PPE for the medical community, using nearly any 3d printer; such as those in the Maker Vault at RCBI Huntington.

Outlined is an approach to designing for model-separation, recommended printer settings, free and open-source tools for editing and slicing, and general production workflow.

The scaled tactic is simple:

1.) Identify existing 3d models which can stack - with each supported by the previous model printed.

2.) Test Stacking and Pinning capability of your printer with a test file


* transparency, to show interior pins


* Separation between upper and lower portion increases from L > R... Leftmost models are fused, Rightmost models are spaced too far...

3.) Separate and Pin models according to your machine's capabilities

4.) Print, iterate, and improve!

Quick Start Guide

Any 3D printer with a build-plate large enough to fit the included file can be made to work experience with 3d printing is required but a basic understanding of adhesion, infill, and support is all that is needed.

Ability to adjust settings in the print slicer of your choice (such as Cura, Slic3r, Prusa Slicer, or others...) is necessary.

We have found PLA to be an acceptable material, and offer the following print setting recommendations to start with - tweaking these according to your own tests on your own machine will be necessary!

Recommended Print Settings:

Shells: 2
Layer Height: 0.03
(*speed and function over quality 😉
Temperature: 210º C
Infill: 20% Cubic pattern
Build-plate Adhesion: Skirt
(*helps ensure good adhesion and bed-level!)

Download and print this Separation test file

Spacing of Separation progresses from L > R* from:
0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm

Download and print this Pinning test file

While the spacing of Separation progresses from L > R* from:
0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm

Just like in the last model... internal pins progress in diameter from
0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm

You can print both files at once on the same buildplate, in under 1 hour!

--This is a great time to crank the speed and watch the quality: as speed increases layer adhesion will decrease - go as fast as possible, but make sure you produce solid, sturdy, useable prints!

*orientation from L > R is according to the photo above... you can observe spacing and internal pins easily in your slicer and note which are smaller/larger

Download and print this stack of 20 which is:

- Separated at 0.4 mm
- Pinned at 0.5 mm

If the spacing included does not work for your printer...

Download the modified, and/or stackable file

* If you download individual files to stack and Separate for yourself, don't forget to add 0.5 mm or comparable Pins, spaced similarly to those in the x20 stack file.

*Pinning note: features of your 3d model below the diameter of your print nozzle will not render features in your model; most print nozzles are 0.4 mm; so 0.5 mm through Pins are recommended.

If you're new to 3D Design, that's OK!

There's an easy to learn free tool from Autodesk that runs in a Chrome Browser window over the web on any computer --and even some tablets...

www.TinkerCAD.com

Sign up for free at the link above and work your way through the guided tutorials!!

In about 20 minutes, you can reach 70% proficiency with this powerful modeling/editing tool!!

- original crowd-sourced face-shield design, as widely used on the ground by medical professionals in Malaysia; supported and developed by this Facebook group...

 

MOST importantly we wanted to reach out, and share our scaled-production tactic we call MASS (or Model As Support System)! This tactic can be put to use where making meets scale... MANUFACTURING!

Face Shield Files:

Recommended material, PETG, alternative materials:

  • transparency plastic
  • thin poster frame sheeting
  • 2 liter, or 3 liter bottles (polypropylene)
  • other clear, resilient, flexible plastics!

If you don't have access to a laser or other means of cutting, try scissors, and a standard handheld hole-punch -- follow the pattern!

Detailed Process

Further details and developments will be posted here as we make progress with the help of the maker-community!