RC3 Compatible Face Shield for 0.8mm Nozzle - Closed Top

grabcad

***EXPERIMENTAL*** - UPDATED 2020-04-02 I've tested this with a 0.010" / 0.25mm shield, but not with the thicker 0.02" / 0.5mm material called for in the original Prusa design. Primarily, I would like to confirm that the lower reinforcement snaps into place nicely on a 0.020" / 0.5mm shield. If anyone has a printer with a 0.8mm nozzle and can get their hands on a shield to test this for me, I would greatly appreciate your feedback! 2020-04-02 UPDATE:Added 3_post variants, renamed previous models with 4_post identifier 2020-03-25 UPDATE:Prusa has just released the RC3 revision of their face shield. The headband was the only part that changed; the hexagon cutouts were removed and cutouts were added to the top and bottom faces to aid in printing headbands in a stack. The top and bottom cutouts will not work well with a wide-extrusion print, so I have not carried those forward to my RC3 remix (I am investigating stacked printing with a 0.8mm nozzle). These models are identical to my RC2 remix, but with the hexagons removed. My goal with my RC2/RC3 remix was to take advantage of the high flow rate of large-diameter nozzles (larger than 0.4mm) to increase production speed. With this design and a print speed of 50mm/s, I can print a set of parts in ~45 minutes while maintaining the full 20mm headband height and the original Prusa strap hooks and shield mounting post layout. This design is intended to be completely cross-compatible with the original Prusa RC2/RC3 Face Shield. With this set of models I've closed in the top of the headband, as has been requested by an increasing number of medical facilities. This is the only change from my previous RC3 remix. I've removed the "stiff" variant from this set since the 3-perimeter walls are unnecessary due to the rigidity the closed top provides. THIS IS INTENDED TO BE PRINTED IN THE ORIENTATION SHOWN BUT WORN UPSIDE-DOWN SO THAT THE CLOSED TOP IS FACING UP. VARIANTS: 4 Post/3 Post: The 3 post variant is designed to use shields punched with a standard US 3-hole punch (4.25" between hole centers). The 4 post variant matches the original Prusa RC2/RC3 face shield mounting post layout and is cross-compatible with shields made to fit Prusa headbands. Brim: It is a common problem to have the arms of the headband lift off the print bed during printing, so I've added a small brim to each arm to help with bed adhesion on the "Brim" models. The brim can be trimmed off with flush cutters. I use Simplify3D for slicing, so the settings below are organized as they are in Simplify's profile system. These settings should translate to any slicer, though they may be named and/or organized differently. CRITICAL PRINT SETTINGS: Extruder: Nozzle Diameter: 0.8mm Extrusion Width: 0.96mm Layer: Primary Layer Height: 0.6mm Outline/Perimeter Shells: 3 Infill: Interior Fill Percentage: 0% ; (Infill disabled) External Fill Pattern: Rectilinear ; (concentric does not seal the closed top well) Support: Generate Support Material: disabled ; (Supports disabled) Advanced: External Thin Wall Type: Allow single extrusion walls Internal Thin Wall Type: Allow single extrusion fill I'm still fiddling with the remaining settings for PETG; I may come back and update this with an optional settings list if I get a profile tuned in nicely. DESIGN REASONING: All wall thicknesses are multiples of the 0.96 extrusion width. This means that all of the walls (minus the intersections) are printed with 2 or 3 straight perimeter passes. Because the extrusion is so wide, we can safely disable infill and rely on perimeters to fill the thicker spots. This eliminates the slow zigzag motions required by rectilinear infill. Additionally, the front strap has been trimmed down to a height of 10cm since the extra material there is not strictly necessary. The material added internally between the underside of the closed top and straps (positive chamfer? extruded gusset?) both adds strength and seals the gaps that can be left at the ends of the fill extrusions which form the closed top.