The Fight Against Covid-19
Combating the coronavirus with an alternative PPE design and production method.
Written by Francis Garing
Rendering of Formation's thermoformed face shield design
In the wake of the corona virus pandemic, everyone from individual makers to large institutions and corporations have developed creative and innovative forms of PPE for health care providers. Face shields, in particular, have seen a number of novel designs and permutations - from 3D printed assemblies to flat cut constructions. While exploring ways that our team could contribute, we found that these solutions have quickly led to a strained supply of clear thin plastic sheet. With experience in designing for a wide range of manufacturing process, our mission was to develop a novel design that could leverage the resources we still have to provide additional support to those at the forefront of this crisis.
In the past couple weeks, Formation has been developing an alternative design for this particular piece of protective equipment to circumvent stressed raw material supply chains for thin flexible plastics like PETG and polycarbonate. In partnership with local manufacturer Thermopro, Formation's designers and engineers have developed a face shield that can be thermoformed out of thicker plastic that normally cannot be used for the ubiquitous, open source designs that require a more compliant material. Since the plastic stretches into its final form during the thermoforming process, we're able to fit more parts per sheet of plastic compared to a 2D cut design. The result is a robust face shield with increased raw material utilization. The design has only two parts, and requires no hand fabrication or assembly other than looping the strap through the shield and around your head.
Design is comprised of a cut-length piece of double-sided Velcro and the thermoformed shield. An optional piece of closed-cell foam may be added for additional comfort.
By leveraging the strengths of the thermoforming process, our design is able to provide a number of functional, ergonomic, and production advantages. Since the plastic is molded into shape, we were able to integrate a forehead landing, eliminating the need for the two-part design typically seen with 3D printed approaches. Additionally, a return was added to the bottom edge of the face shield. This serves to diminish the potential of respiratory droplets entering from below the shield's bottom edge, further protecting the user and prolonging the life of their respirator/mask. Additionally, this feature stiffens the shield face to make it more durable and allows the shield to be shorter, which provides greater freedom of movement for the head of the wearer.
Anthropometric models of 5th percentile female to 95th percentile male heads were used in development.
To develop and evaluate this design, our team based our CAD geometry on a range of anthropometric models to provide the best fit possible for a 5th percentile female up to a 95th percentile male head. For additional validation, 3D printed models were created to fine-tune the final fit.
3D printed low-fidelity validation models
Using the large format CNC machining center in our in-house prototype lab, we were able to quickly fabricate a prototype tool for our thermoforming partners, Thermopro. Their guidance and expert feedback were instrumental in designing and refining the tool quickly and efficiently. In the coming week, this will be used to produce an initial run of parts for final fit checks, expert user feedback, and production process refinement.
Formation is actively seeking out hospitals and institutions in need of PPE supplies. If you'd like to learn more, please reach out to us at collaborate@formationdesign.com
See design progress and evaluation process in this update post. Stay safe and stay tuned for more updates!
UPDATE: Face masks are available for purchase here.