This is yet another stackable shield, or ASS for short. (Yes, really)

It's another 3D printable frame for a face shield to help taming COVID-19 transmission probability. Additionally requires an A4 clear sheet and an elastic band.
It can be stack printed, meaning parts can be printed over each other, because the top matches the bottom. More parts per print job means more time printing and less man time managing prints.
A version with included brims just at the end of the frame's arms is available to help bed adhesion where it's most needed without wasting filament on a full brim made by the slicer software.

HOLE TEMPLATE

The template for the clear sheet holes is the standart ISO 838 A4 European 4 holes:
( )--------80mm--------( )--------80mm--------( )--------80mm--------( )

PRINT SETTINGS

• Layer Height: 0.25mm
• Line Width: 0.5mm
• Wall Line Count: 3
• No Infill
• No Support

Minimum printer bed dimensions are 160x160mm.
It should print in less than 1h and use about 20g of material per part.
AMF (preferable) and STL file formats are available.

STACK PRINTING

-In Preferences, untick Automatically drop models to the build plate
-Multiply the Object
-Move to same X and Z of the first object
-Move Z to the current total Z dimension (bottom left in Cura) +0.25mm
-Slice and Preview, there should be a 1 layer gap between each object

Unfortunately Cura doesn't respect the gap between objects and uses Layer Height to adapt to it, forcing us to use the same value in both to keep consistency.
The ChangeAtZ Post Processing script on Cura allows to change settings like printing temperature and speed on a single layer, lowering both on the first layer of each part might help.
Or if you're comfortable editing gcode, you can insert M104 S to lower the temperature for the first layer of each object (except the one in the bottom) so it doesn't adhere as well to the part below, and then another M104 S for the second layer of each object so it goes back to the normal printing temperature.

DESIGN

This part was designed in FreeCAD, a free and open source CAD software available for Windows, macOS and Linux.
The FreeCAD file is provided and the features and sketches are labeled, so anyone can understand and modify the design as they wish.
A STEP file is also provided.
A spreadsheet in the ODS and xlsx formats is provided for the arc calculations in the sketchThumbs sketch, so the thumbs match the hole template.

CAUTION

This shield in no way guarantee immunity to any transmissible disease, it only tries to help lower transmission probability. I can only guarantee this is better than nothing.
All other forms of protection should keep being adopted. Avoid any false sense of security.
If you're printing for others, give priority to those in the first line of this fight who need it the most: Medics, Nurses, Paramedics, Law Enforcers.

LICENSE

This thing is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0).
This is done to ensure anyone is and will keep being able to share, redistribute, modify and commercialize this thing, with the only requirement being credit attribution to the creator.

Created by Filipe Caçador