Current Project

Laser Cut Face Shields/

4/2/2020

10 Shields Delivered to Valley Hospital

Summary

On Thursday I was able to deliver 10 safety shields to Valley Hospital.

This was made possible by Lilian Labowsky who was able to get a small order of plastic to try, she has also reached out to her brother in Taiwan to try to secure a shipment of disposable shields and gowns. Valley has indicated they need 300 shields and 300 gowns as or 4/6/2020

I was able to use the laser to cut and assemble the plastic,took about 15 minutes per shield to cut/ peel and assemble using our laser. These are not up to the complete specification, but we hope it can be useful to them in some way.

The goal of the shields is to provide an immediate and re-useable shield to extend the life of their current solution.

What problem we are addressing

Face shields are used by close contact medical professionals to deflect airborne virus. It is just an added measure and does not fully protect the user. See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5015006/

Fortunately, the face shield supply has increased dramatically recently and we are hopeful that the need will be met very soon. Mayor DeBlasio recently announced NewYork's face shield and goggle supply will be met by this Saturday.

April 1st briefing Mayor Bill de Blasio: (02:45)

"So we are confident based on all our projections that for next week, we will have sufficient eye protection, that means the face shields and the goggles and sufficient surgical gloves for all those needs "

The current disposable shield is a flexible foam glued to a plastic lens then stapled to a plastic strap. Volunteers have been making these by the thousands at the Brooklyn Navy Yard as well as at many professional factory sites across the nation. As designed they are meant to be disposable.

Trying to re-use the current shield presents some problems.

The foam dissolves when in contact with the disinfectant and the lens acquires a haze that must then be polished. The strap must be discarded then reattached with new staples that can split/crack the ends. The foam cannot be disinfected using their current method.

New--A disposable shield with plastic wrapped foam is now being used, this improved design protects the foam from dissolving in alcohol allowing some re-useability.

Our Solution

Georgia tech developed a laser cut shield design https://pwp.gatech.edu/rapid-response/

It addresses the reusability as the shield and band snap together and all plastic is FDA approved.

Our Challenges

Equipment

Our Laser , Epilog Mini, is too small and underpowered to effectively cut the plastic. A redesign of the model has made it possible but is limited. Our cutting rate is aprox 10 minutes of laser time per shield and it must be hand fed into the laser. A larger laser can do this in 2 minutes. Another larger laser in town was tested and can be used but he is only interested if we have a large order (100-200 shields)

Material

Lens material PET-G is in scarce supply, we were only able to source a thicker lens than the design calls for and it is not pre-cut for the specifications of the laser presenting problems with assembly, requires hand cutting (5minutes) and wastes a lot of material.

Frame material 3/8" polycarbonate is recommended- It is available and must be ordered through specialty suppliers, the thickness cannot be cut on our laser in one pass. For our initial production we used 1/4" acrylic as a substitute. It is not ideal as it doesn't have the strength or shock resistance of the polycarbonate, but is readily available at Home Depot and our laser can cut it.

Some lasers cannot cut polycarbonate- we will begin trials as we receive materials.

Funding

Initial projections are $13-$20 per shield for all materials if bulk order. Plus any fee to the larger laser operator.

There is no call for funds at this time until we have a deliverable project

Volunteers

All the laser cut plastic is wrapped in a thin plastic film on both sides, it requires pulling the film off, clipping the shield to the frame and attaching the back strap or band, about 5 minutes work.

There is no call for volunteers at this time for the scope of this project, please contact Valley Hospital's website

https://www.valleyhospitalfoundation.org/COVID19HowCanIHelp

Using a design released by Georgia Tech, we have successfully cut prototypes on the High School's Epilog Mini Laser

We have also used a larger size Laser provided by Ridgewood Resident Joe Ring to test the design.

Current Status- a new revision to the design found here https://pwp.gatech.edu/rapid-response/face-shields/

As of 4/1 the project is awaiting a small shipment of plastic for the shield material, which has been impossible to acquire.

The Shield Material we are looking for is PET-G .004 to .010 thick

We are hoping to receive a small amount by Thursday 4/2, however it is .20 to .30 thick and will try to get it to work.

We are still actively searching for a supply of PET-G that will not hinder the efforts of professional manufacturers. Although we have the ability to produce shields, all the material is being diverted to larger operations with huge capacity and ability to produce without contamination. We even secured a shipment of 500 complete shields only to have it diverted through a government procurement . Laser cutters and 3d printers are prototyping machines not designed for production work.

The news is uplifting as many suppliers have been working on this problem and through our channels see that many supplies will be coming online soon. Our goal is to fill an immediate need. Our consultations with doctors at infection control at Valley Hospital have identified that the current "disposable shield" that they have been using has problems with disinfecting as the wipes will dissolve the foam cushion and cloud up the shield. This reusable design works without the foam cushion, and has a replaceable shield and replaceable comfort foam forehead tape allowing a longer use life.

Needed for Face Screen of Shield

At this point we are only looking for backstock or a small personal stash of PET-G . The thickness should be .004 to .010 thick and we will also take up to .030. It must be film wrapped. This is mostly used in the Printing , Advertising and Display Fixture Industry The thinner stuff often comes in rolls while the thicker in sheets film wrapped.

Needed for Frame of Shield

3/8" thick Polycarbonate sheets, FDA approved Nylon, or Acrylic in order of Best to worst. Any color will work

Needed Accessories (these items have been easy to get)

7" long Hook and loop (Velcro) nylon strap or Rubber Bands

3/8" foam adhesive weatherstripping ( by the roll)

Georgia Tech Design-- New Release 3/31

Data Found Here https://pwp.gatech.edu/rapid-response/face-shields/

3d Printing Tests

Face Shield-- Based on the Prusa 3d printers design-- Modified to work with 3 hole punch for transparency sheet

3/25/2020 Raise 3d test print-- 2 hour print time

Files for download

Laser printer trials 3/27/2020

Here is the latest

I had a meeting with a doctor at Infection Control at Valley, the prototype was delivered and we are awaiting feedback. There was talk about using transparency film, the doctor rejected it as being too thin. The face must be thicker plastic .05 inch is the preferred. I picked up some Acrylic and Polypropylene on my way home and will head to the Makerspace tomorrow morning to try and laser it after I get the design flushed out.- JW

Casting Plastic Test Results

Cast plastic bands using Smooth Cast which is a Shore 70 durometer plastic