MakerNexus local modifications

At MakerNexus, we're working on making as many face-shields as possible; They will be in dire demand very soon and we got requests of thousands of them. MakerNexus is coordinating the contact with the local hospitals and as well the effort of non-Members of the maker-space to 3D print. We have enough shield material to laser-cut, but of course 3D printing is the slow part of manufacturing.

Please check out the project page if you are in the San Francisco Bay Area and want to help.

We are using the Prusa-rc3 design, but needed some modifications requested by the local healthcare community.

Design goals

When reviewing, the local healthcare providers requested

• Weight-reduce front-part if possible.
• Move the shield pins up so that there is material behind the openings of the shield-punches
• Larger radius of crevices to allow better sterilization access.

Moving up the shield-pin requires a little bit of support material, but it is not a problem to generate the necessary STL file where the supports should be and use that in the Prusa slicer as support modifier.

Download

Choose what bests fits your circumstances. GCode is 'ready to go', 3mf allows printer adjustments, *.stl allows to use in your own slicer.

You can just use the files below directly. If you want to work on the repo, pull requests are welcome, but please discuss things first on slack.

Release content

We are only printing the 'thin' shield version now (15mm vs. 20mm before).

Cut to the chase: GCode ready to use

Recommended

• For PETG T9-PETG-Prusa.gcode (right click, download or save link as...) GCode file placing 2 head-bands on build-plate. Ready to go on Prusa MK3(s) with 0.3mm layer, 100% infill, 240°C temp for PETG printing. This prints two thin bands which is faster to print and works fine with PETG.

• For PLA T9-PLA-Prusa.gcode (right click, download or save link as...) Same for PLA. Currently this is the regular sized band as we still need to test if the thinner band will work with PLA.

The resulting headband has a version imprint on one temple with a letter denoting T = thin band, and s = stacked, followed a version number.

More files

• thin_shield_with_support.stl and thin_shield_no_support.stl. The with_support version has already a support column included for printing the pin. Make sure you have thin wall detection enabled in your slicer. If you choose the no support version, you need to use your slicer to create support for the mounting pins.

If you have checked out code from github, you might need to first make it and reload the STLs in the 3mf. The STLs and 3mf are usually only updated in git for a new release (click on the stl in the list on the right in prusa slicer and say 'reload from disk').

Stacked arrangement

There are 3mf's for stacks and makefile-rules to create various height stack arrangements. The 3mf's with 'FAST' in their name are tweaked for very fast prints, but it requires some tweaking depending on your filament to get the flow-rate right and the separability correct. For details about the speed improvements see the Fast-Stacks documentation.

The way these stacks work is that they have a one-layer gap between them, with the intent to have a weak layer adhesion there to be able to separate, but still strong enough to print the next layers. This is the reason why it also requires some tweaking which is very dependent on the printer and filament you have, so we don't distribute any GCode. The gap height is 0.25mm, so this is the layer thickness needed in your slicer (or modify the print_layer_height in the Makefile).

If you use a different slicer than Prusa slicer, you can also create STLs for the stacks and slice these.

make fab/thin-stack3.stl

Faceshield

The face-shield has been optimized at MakerNexus to meet the needs of the healthcare workers to be also protected above the headband. You find the maker-nexus-faceshield-cut.svg file and maker-nexus-faceshield-cut.dxf in the baseline/ subdirectory

Code

A simple OpenSCAD file that take the original STL and does the necessary surgical changes.

Slicer project file

A 3mf file is provided, so it can be loaded into slicer right away:

git clone https://github.com/hzeller/prusa-covid19-shield-remix.git
cd prusa-covid19-shield-remix
prusa-slicer thin_shield.3mf

GCode

There is also gcode directly sliced for Prusa MK3(s). See above.

Development

For building, use the Makefile to create all the artifacts from the *.scad file

make

License

License: CC-BY-NC

This is based on the Prusa design https://www.prusaprinters.org/prints/25857-prusa-protective-face-shield-rc2