St. Luke's University Health Network and Filament Innovations worked together to create a 3D Printed mask to help with the supply shortage, which can be sterilized and re-used (minus the filter). These masks do require the use of a filter which the person printing has to supply and the filter should be oversized when it is cut to help seal the mouth area.
Filament: TPC/TPU at 95A Shore Hardness is suggested as a first choice and PETG as a second choice.
Assembly: There are four parts to the full mask assembly (in order) -
- 3D Printed mouth area / guard - this houses the filter and the laser cut acrylic piece and press fits onto either the Medium or Large mask
- Laser cut acrylic plate at 1/8 (3.2mm) thickness. Note* an STL is included of a version that can be printed if a laser cutter is not available.
- HEPA Filter.
- 3D Printed Mask in either Medium or Large.
Notes: The 3D Printed mouth area/guard is printed using one perimeter and 100% infill. The 3D Printed mask is a split process which prints the bottom, square area using one perimeter and 100% infill, and then the facial area itself is printed using spiral vase mode. Spiral vase mode is needed as it eliminates retraction, multiple perimeters, and creates a seamless print, which when combined with a 0.9mm nozzle, would generate a truly solid print. We suggest 1.50mm single wall pass when you start to print the area with the face. The spiral vase mode sequence should start at the 7.13mm layer height of either the Large or Medium model. Simplify3D is the only tested and suggest slicer to use for this.
This method of printing would yield the best chance, in our opinion, of creating an airtight 3D Print using FDM technology. The larger nozzle (0.9mm) and larger layer height (0.4mm) appears to increase bonding in the Z axis, making a stronger and more durable print. When assembled, using flexible filament, the TPC acts as a gasket; creating an air-tight assembly around the mouth and nose and ensure that ensuring that the wearer can breathe through the mask .
TPC/TPU is the recommended filament.
Users have passed a FIT test using Bitrex or Saccharine. Masks can be sterilized and reused.
