Flip Up Visor modification for DtM 3.1 Face Shield

thingiverse

Description --------------- This is a remix of the DtM 3.1 NIH approved face shield with a print-in-place hinge to allow the visor to flip open. The shield profile is also modified to wrap around the sides more (similar to the DtM 4.0 injection mold version shape); as a result, there are also tabs added on each side to help secure the shield material. I have also included a non-hinged version with the same profile and side tabs. Revisions: 12/17/20: Mk2 - simplified hinge area to only have 2 detents (middle positions drooped with use anyway); decreased hinge gap clearance from ~0.5 to 0.3 mm to reduce loosening over time. Adjust step file as below to further tighten or prevent fusing as necessary. . Materials ------------- The frame can be printed with any PLA or PETG filament Any transparent sheet can be used for the shield itself - mounting holes are for a standard US 3-hole punch as with the source design, and the side tabs accomodate up to 11.5" width (or slightly oversized if the corners are rounded). Heavy (8 mil+) transparent report covers work quite well. Due to the mounting system, the thinner, overhead projector transparency sheets are more likely to rip, and do not hold shape as well. The bottom curved reinforcement shown in the photo is optional; the original Prusa RC3 reinforcement available [here](https://media.prusaprinters.org/media/prints/25857/stls/260466_f1e0f39c-88fe-4b35-a909-0348aa53e412/bottom_reinforcement.stl) works well. Foam insulation tape can be used to cushion the headband if desired; a towel or gauze bandage can also be wrapped around the frame for the same purpose. Printing Parameters --------------------------- Use layer height of **0.2-0.28 mm** - smaller layer height is overkill and just dramatically slows the print; I have not tried larger heights but it might cause the hinge portion to fuse. Extrusion width should be **increased to 0.6 mm** (150% on a 0.4 mm nozzle) - this will help speed the print, and reduce the likelihood of the hood portion delaminating/failing. Use 3 perimeters for strength; infill can be 0-25% (basically only cosmetic and helps to make the "roof" of the elastic hook section to not cave in if your printer does not bridge well). As long as you use 3 perimeters, top and bottom layers can actually be set to 0 and it will retain its structure and save a few minutes of print time, but a few areas will have a "wireframe" appearance. Set to 2 layers to have a better cosmetic result. With these parameters and some basic velocity tuning, I got a print time of just under 2 hours with PLA on my (not particularly well calibrated) Ender 3 for the hinged version, and 1:45 for the non-hinged version; PETG print times are about 30 min slower (my printer is finicky with PETG).