Face Shield Visor CR-3D remix wireframe fast print large stacks

thingiverse

This is a fast print wire frame remix of the popular and highly optimised German CR-3D C8.1 design. I further optimised it using Manufacturing Systems Engineering design principals I learned at Delphi Technologies. Resulting in lower weight, easier printing, large 50x stacks on a delta printer and lower material costs. With this design I can make ~30 a day running overnight. 50x stack takes ~1.5 days. I have included all of my various stack sizes STL files so you can select what fits on your printer. ---------------------------------------------------------------------------------------------------------------------- -Hole pattern and visor material- Uses 888 4 hole punch pattern as per CR-3D original design. Enables very fast processing of laminates compared to prusa hole spacing. Recommend using 250 micron laminates for stiffness. Thinner will still work ok with the bottom chin reinforcement. If users need fine detail vision (eg tatto artists) then recommend using A4 0.5mm PETG sheets from amazon or potentially overhead projector acetates as a cheaper alternative. Use washing up liquid trick as a cheap anti fog solution and inform your users. ---------------------------------------------------------------------------------------------------------------------- -Cycle time and cost- Prints in ~30 minutes per part (not including reinforcement). I get ~50 face shields and reinforcement pieces to 1 KG of PETG filament. Total cost of manufacture, sterilisation, elastic, zip ties and packing ~£1 No infill, no top or bottom layers, just 2 walls printed with a 0.6mm nozzle. Can also be printed with 3 walls and a 0.4mm nozzle. ---------------------------------------------------------------------------------------------------------------------- -Wireframe design optimisation origin- Based on the wireframe optimisation a user called mike applied to the prusa RC3 design called 'RC3 Stack - High Speed Print'. I applied the same technique to the CR-3D design. Requires a solid fill model where you only print the walls. ---------------------------------------------------------------------------------------------------------------------- -Changes to CR-3D C8.1 design- I re engineered the CR-3D STL file and made some ergonomic tweaks based on user feedback. The STL is a simple mesh for fast slicing and low computational load on the printer G code path when printing to avoid stalling. This version is taller. 13.5 mm tall for comfort, 0.3 mm layer height and to match the top of laminate using a 4 hole 888 punch. The sides have been extended back to stop pressing on sides of the head. A flick/curve added to the ends so there is a radius and doesn't poke the end into the skin. Slightly modified the hook geometry so it also had a vertical hole through it which any elastic can be tied to. Removed text (sorry CR-3D) because causes instability in the tool path when only printing two walls with a high material flow. Added an optional bottom reinforcement also to 888 4 hole pattern. This bottom reinforcement features 2 side loops that are intended for a 300mm 4.6mm wide zip tie. This helps for a tapered cone for a closer fit and the user can tune the curvature as desired. ---------------------------------------------------------------------------------------------------------------------- -User experiences- When printed in PET G fits toddlers and adults alike due to the flexibility. No failures in the field reported yet after 2 months. Over 400 distributed and used by healthcare staff, care workers, the public, transport, retail in the UK. Users prefer this over the Pusa design ---------------------------------------------------------------------------------------------------------------------- -Sterilisation procedures- You must follow Prusa sterilisation guidelines when packing. Act as if you have COVID. Wear gloves and a faceshield as a minimum. Preferably a mask as well. Work in sterile conditions. Individually bag in zip lock bags immediately after sterilising. I use Ethanol (surgical spirit) bath as per PRUSA sterilisation guidelines. Other options such as alcohol, UV-c light, weak bleach solution also an option. PRUSA advice: If you want to manufacture shields for others PLEASE READ THIS CAREFULLY Act as if you were infected by the COVID-19 virus. Wear a face mask and a fresh pair of gloves when collecting each batch of printed parts. Store the parts immediately in a sealable bag. Talk with whoever you’re making the shields for, let them know about your manufacturing environment There is still debate about how long the virus survives on plastic, but most sources mention 2-3 days. That means that by letting the packed face shields sit for 2-3 days before distributing them, you’ll greatly reduce risk of transmission Do not store the entire stock in one place, minimize the risk of cross contamination Source Josef PRUSA ---------------------------------------------------------------------------------------------------------------------- -Licence and selling of face shields- We share these files under non-commercial licence. It would be great if you donated these shields to those in need for free. If you need to cover your production costs, we are ok with you selling the shields for production cost. However, we do not want to see these shields on eBay or amazon for extortionate costs. Also commercial 3D-printers are allowed to print this file and can cover the production costs! <- taken from CR-3D description Please accredit CR-3D for the ergonomic design of this faceshield as I have only optimised it for large batch production and made minor tweaks based on feedback. Ensure your users know the design origin as their work has surpassed the original Prusa design in my opinion and is why i made the switch.