Description

The HensNest v2 About the Design The HensNest was created to address some of the most pressing issues with current face mask hacks. It was inspired by both The NanoHack by Copper3D and the DIY Face Mask by Mark Fuller. The HensNest has a flexible printed hoop frame that conforms to the face without post-processing steps, like using a heat gun or applying a sealant. The filter surface area is very large, addressing issues with the breathability of hard-sided mask designs with small filter towers, like The NanoHack. The HensNest adds a tented structure to the design that keeps the filter surface away from the mouth and nose, which we learned from our clinical collaborators is critical for keeping the filter dry and functional during extensive use. Lastly, this design is mostly planar and is fast and cheap to print. If you have design improvement suggestions, please post to the comments section below. Release Notes for v2.0 The v2.0 HensNest design is production ready and includes complete assembly instructions (https://youtu.be/C6Wwg1U_tFQ). We are continuing to make minor tweaks to the design and will update these release notes as we progress. DESIGN MODIFICATIONS: HensNest v2.0 features two important design improvements from v0, namely, (a) an interior retaining ring that secures the filter in place; and (b) ergonomic improvements to the lofted wireframe to fit more comfortably around the nose while holding the filter material further from the face. FILTER MATERIAL: We have been experimenting with several commonly available filter materials, and our current recommendation is to use one ply of a (clean!) furnace filter. We recommend higher performance filters like 3M Filtrete Ultra Allergen Air Filters (https://www.filtrete.com/3M/en_US/filtrete/products/smart-filter-technology/?gclid=EAIaIQobChMIyMeNxobX6AIVDRQMCh32sgQ8EAAYASAAEgJn0fD_BwE&utm_term=cbg-chim-filtrete-en_us-ba-paidsearch-cpc-google-na-na-na-ne19&ef_id=EAIaIQobChMIyMeNxobX6AIVDRQMCh32sgQ8EAAYASAAEgJn0fD_BwE:G:s&s_kwcid=AL!5388!3!290907499123!b!!g!!%2Bfiltrete%20%2Bfilter), which have an MPR rating of 1500. We are still in the process of respirator fit testing this design, and we will release these results as soon as they are available. SECUREMENT STRAPS: Current assembly instructions for HensNest v2.0 incorporate household rubber bands to secure the mask to the face. We present both a 4-point and 2-point securement option, with the 4-point being more strongly recommended. We recognize that comfort is a priority for longer duration use of the mask, and we are presently working on slight design modifications to improve the comfort of the securement straps. Release Notes for v1.0 We released HensNest v1.0 to give the maker community a chance to further “hack” our improved wireframe design. We will continuously release design improvements and updates related to the wireframe design and all of the release notes listed below. ASSEMBLY: Assembly for The HensNest is similar to the DIY Face Mask by Mark Fuller and involves first securing the disposable filter within the wireframe. Rubber bands or elastic straps should be connected at the four tabs on the wireframe to create two continuous loops around the head, similar to a disposable N95 mask design. We will release detailed assembly instructions and an assembly video very shortly. STERILIZATION: The HensNest was designed with the intention of having a disposable filter (more on that in a sec) and a reusable wireframe. We recommend printing the wireframe in ABS to allow for both heavy disinfectant use and steam sterilization via hospital sterilizer or home dishwasher. If you’re printing in PLA/PETG, recognize that it will likely not be tolerant to steam sterilization but should not excessively degrade with bleach or alcohol disinfectants. FILTERS: Right now, we are experimenting with different filter types to achieve as close as possible to an N95 rating (knowing that we will not really achieve N95 rating). At present, we are testing vacuum cleaner bags, household heater air filters, and any other common filters we can get our hands on. We are fortunate to have an environmental safety and health officer at our institution who can run both qualitative and quantitative respirator fit tests. We will post these results as we get them. If you have suggestions for other filter types, please post to the comments section below. About the Team The HensNest is a collaborative project from the University of Delaware’s (UD), home of the Blue Hens. The design was conceived and early prototypes manufactured in The Design Studio (https://me.udel.edu/academics/design-studio/) , which is an undergraduate teaching and learning makerspace in the UD Department of Mechanical Engineering. The project is led by Mr. Whitney Sample, Co-Director of The Design Studio and an industrial designer by training. Whitney has extensive experience in medical device design, and he “hacked” the HensNest design over the course of several lo