While most of us were able to shelter at home, key workers were forced to come into daily contact with COVID19 as they attempted to treat its victims. They worked long hours in an NHS that struggled to cope with seasonal demand and even worse these doctors and nurses faced another threat, one born out of a very real failure to prepare for the outbreak –– shortages of personal protective equipment (PPE).

But thanks to an army of volunteer enthusiasts who have been crowdsourcing local 3D printing capacity, dwindling supplies of PPE have been boosted in the face of Covid-19. We talk to these unexpected heroes of the COVID 19 battle and ask how this might bring about the 3D printing revolution we’ve been promised so many times before.

Thin Supply Chains

We have known for a many years that UK supply chains are long and thin. Spindly, with no buffers built in to protect against unforeseen problems. They stretch all the way back to countries that can mass-produce what we need most cheaply. Combine this with just-in-time manufacturing and you have an industry that is hugely vulnerable to sudden disruptions. The shortages during the outbreak revealed our gaunt supply chains. As politicians dispatched RAF planes to investigate supply hold-ups in Turkey, and businesses nervously awaited the return of regular cargo shipments from China, to any it seemed that the time was right to look at building safety buffers into our reliance on global logistics.

But re-organising the global economy in the future doesn’t help vulnerable NHS workers today, who are left without adequate supplies of PPE and don’t have time for major suppliers to recover. Fortunately those people can rely on people like Tony Thompson. “My name is Tony Thompson. I’m currently working at Northampton College as an engineering and an electrical assessor,” he says as he tells us why his alarm clock sounds at 3am every morning.

Before even the birds are awake Tony has slipped quietly out of bed, although not as quietly as his wife would like, and heads into his man cave where he keeps some very special equipment.

But Tony said that after a while the excitement of printing little bits of plastic that other people designed wore off and he started to prefer working on his own designs. That was until the coronavirus hit Europe. Now using a Creality Ender 3 printer, which he says is infinitely better than his first, Tony realised he could help in the current crisis.“I’ve started to now do PPE for NHS, key workers, a lot care workers things like that how that came about was mostly involved in a lot of 3d printing groups and that sort of thing. And I got a message asking would I be interested in helping out a group called Print for Victory.”

Print for Victory

Print for Victory is a local volunteer group that is organising people to 3D print face shields and then distribute them to those who need them most. The group connects their volunteer printers with people who need PPE that live near them, and when we spoke to Tony in early May, he and Lyn had just completed their 700th face shield. The shield consists of a 3D-printed headband with a slot that allows an A4-sized acetate or similar clear plastic sheet to be inserted, forming the shield. But first comes the headband. Tony explains. “First of all, there needs to be a design now this will be something drawn up in a 3D CAD package. And there’s quite a few free packages available. Once you’ve got the right design, you have to prepare this design to go to a 3d printer. And you use a package which is called a slicer.”

A slicer looks at the 3D model, which at this point is basically a 3D shape with its surface made up of lots of triangles. The slicer, as the name suggests, then slices it into layers. This is then converted into G-Code, which is a language used to tell a machine to perform an action, such as move a printing appendage. ”Now what G-Code is, is basically just coordinates you have an X and a Y, which is across and behind and then the Z which is the height.”

Then it is time to print using a plastic known as PLA – polylactic acid, or polylactide. Which is one of the most popular materials for desktop 3D printing. “I use PLA, because it’s one of the easiest plastics to print with. It’s also biodegradable, which in this day and age is always a bonus and that comes in a wire form which is about 1.75mm in diameter. This plastic wire is then fed through a hot end and the hot end you heat to around about 200 degrees.”

“So, what happens then the G code will instruct the printer to feed out a certain amount of this molten filament and it will basically draw the outline of the shape on layer one. Once it has the outline, it will then colour it just like colouring it will go backwards forwards at an angle it will colour in the first layer, then it moves up a layer and it does the same. It will colour it in the opposite angle obviously that gives you a better strength”.

Tony can fit three headbands on his print bed and complete them in two hours and thirty-five minutes. Next comes the actual face covering. ”We then use an acetate or laminate, a clear plastic sheet basically of A4 size takes about hundred 50 to 240 microns thick depends on what you can get materials are difficult to get hold of at the moment and that will slot in to the front of the face shield. So that can be removed, it can be cleaned, it can be changed if you want to. You can put a thicker one in if you’ve got a thin one.

Thankfully there are lots of designs out there to choose from, this is down to a global response from the 3D printing and design community. But Tony hastens to add that this is an emergency protective shield. Under normal circumstances and with normal availability of equipment, this sort of face shield should not be used and it has become termed secondary PPE. “Because it is homemade. It doesn’t carry sort of any CE mark or British Standards or any of that type of regulation. However, Print for Victory have put together a disclaimer sheet. It’s not just a disclaimer sheet it tells you how to look after the mask, how to disinfect it.”

In high-risk roles, users wear fully approved masks underneath the shield. The crowdsourced PPE functions more like a splash guard, and will provide protection if someone coughs near the wearer. “It will have a massive effect of reducing the likelihood of anything actually getting to your face.”

De-centralised Manufacturing with 3D Printing

The speed, and the sheer number of volunteers that have answered the call for assistance, has been incredible. This is Mark Hester, co-founder and the technology director for the Imagination Factory, a product design and creative engineering agency that, under normal circumstances, makes use of 3D printing for some prototype fabrication work. “This is the first time I’ve actually been able to see de-centralised manufacturing working,” says Mark. “And it’s because there’s, there’s been such a great demand for the product. And because it’s been very localised demand, so you’ve got a hospital here or a GP surgery there. And because you’ve got these hubs that are then able to draw in the products from local makers, and deliver them within a very short time period, at a time when the typical supply chain is broken and has revealed all of its weaknesses.”

Mark’s experience with 3D printing goes back to the early 1990s, when he got a job as a model maker at a design agency in West London using a process called stereo lithography. “It felt magical to have this part in front of me that had not been machined or made by hand had literally been built by a computer with or built by a machine being run by a computer with a bath of resin and a load of lasers. I mean, that that just sounds so cool, right?”

But in practice, 3D printing still had limitations. It was a very expensive process. The parts were extremely expensive, and only professional design companies would use them for prototypes. But things have changed a lot since the 1990s and not long ago Mark received a call from a friend who urgently needed PPE.

It was an emergency response to quickly make something, sterilise it as far as was possible, and then stick it in a bag for a bike courier to take it on to where it was needed. “That made me start to think that maybe there is actually a way in which that we can use 3d printing to really help with the situation.”

Mark found himself volunteering his time and his printer for one of the larger groups in the country, 3DCrowd UK. The group organises some 8,000 volunteers and as of 8 May, had produced 126,000 face shields and had received 600,000 orders.

“One of the things that made me feel that 3d crowd would be a good organisation to get involved with was the fact that they had decided to ask their members to only make from one particular 3D file.”

This was a face shield developed in Czechia, until recently the Czech Republic, by a company called Prusa. A major player in 3D printing for decades. They worked with the country’s health ministry to produce something that they were able to get approved for use as PPE. “So, at the time, that was the only thing that had got that far, and that had been considered in in that way. I realised that this organisation were actually at least thinking along those lines and trying to work out what’s the best practice – what’s the best way to do this.”

Creating Standard Procedures

3D Crowd UK had some people printing the headband and other members providing the clear plastic face shields, the components are then assembled at a hub before being sent where they are needed. Like Print for Victory, 3D Crowd UK is having its members produce secondary PPE, without yet having the CE mark.

It is an unusual experience for Mark, a professional designer used to only ever working on products that have appropriate standards and regulations. “It definitely made me at times uncomfortable… but then also having had that personal contact from someone who said: “Look, I just need to wear something”. It made me realise that so long as so long as we were following the standard operating procedures, then we’re doing the best we can.”

A benefit of having an organisation acting in sync like this is that any updates to the design, or changes in best practice can be rolled out quickly. “Everyone’s kept aware of what’s the latest version of this document, you have to make sure that you do everything according to that, which includes keeping your workstation clean, and making sure you’re wearing PPE yourself.”

Mark is one of the volunteers producing the headband for 3DCrowd UK, to do this he is using an Ultimaker 3 printer from a manufacturer called Ultimaker, which is based in the Netherlands and has been making printers since 2011.

To keep such a vast movement of volunteers working in unison, 3D Crowd UK limited the types of materials that it approved for use in the head bands. ”There’s two materials which 3D Crowd have asked us asked us to use. The Ultimaker can print many different materials, Including sort of flexible, rubbery ones right through to carbon fibre loaded plastic, things like that. But for the purposes of the headbands, they asked us to use a material called PLA.”

The same material that Tony Thompson is using. And the second material that 3D Crowd UK asks its volunteers to restrict themselves to, is PETG, typically a version of the material that something like a drinks bottle would consist of.

New 3D Printing Designs Emerge

Volunteers across the country such as Tony and Mark have been working to boost the supplies of protective equipment in the face of an unprecedented surge in demand that has seen traditional suppliers unable to react quickly enough. The time these volunteers have bought has allowed new designs to emerge. One of these was designed by The University of Nottingham’s Centre for Additive Manufacturing. They have been working with support from local partners Matsuura Machinery UK and Ricoh UK, Prime Group and Nottingham Trent University to produce a face shield that would not only pass the rigorous BSI tests, but would also be built using methods that would allow it to be mass-produced.

We spoke to Professor Richard Hague, director of the centre who we first met with for episode 19, which explored the future of 3D printing.”Most of the visor initiatives have been printed with fused filament type printers, what are called fused deposition modelling system (FDM) printers and you can use a range of materials on these. And PLA is a very popular one.”

But the centre has found that it needs to be a major supplier in its own right, and in the immediate future has been tasked with delivering 5,000 face shields to frontline NHS workers in Nottingham. A production target that Richard says would take them a week. “We discounted the use of these FDM printers for these visors and the reason we did that is because they’re not very scalable, you have like one nozzle printing the whole thing and printing you know, thousands of these is quite hard and so we wanted to have a more scalable option.”

The more scalable option involves a powder bed fusion technique, of which there are two versions. “You can use one that uses lasers to fuse the powder together. So that’s selective laser sintering and there’s another from HP where they effectively jet an infrared absorbing material into the powder bed and then selectively melt that part together,” says Richard.

The main powder that is used by Nottingham is nylon 12, also known as polyamide 12. And many more units – up to 70 at a time – can be made per printer in a 24-hour print cycle.

But just as crucially this method allows for improved geometry in the print, which has allowed the team to include one very important feature on their product: a covering above the eyes.

Richard’s team is also looking at the reusability of their face shields. “What we’ve tried to do is create a 3D printed headband that is reusable and a strap that is reusable and can be cleaned with the standards, techniques that the hospitals or healthcare workers would use. But then have a visor that is replaceable. So there is a replaceable element on this. But it is one where you can basically unclip the visor and put a new one on.”

Five replacement visors are being packaged as part of each face shield produced by Nottingham. Because of these improvements, and although the announcement had just gone out when we spoke to Richard in early May, he had already received interest from other groups wanting to make use of his work.

“We’ve unwittingly become manufacturers of things,” he says “But we’re not going to be able to supply these in their millions, right. So what we’ve tried to do is make our designs open source. So we’re very happy for people to go away and take our information and create their visors.”

He adds that although people would be working on visors created to a CE standard, the actual approval refers to Nottingham as a manufacturer. Other people’s processes and systems haven’t been evaluated and so any PPE wouldn’t be automatically CE approved. Although BSI has created an expedited route to get this accreditation in recognition of the present need.

Future Potential

The COVID 19 pandemic has shown that for simple but functional products with ordinary materials, a distributed base of small-scale manufacturers can be very effective.

However, at the higher end of additive manufacturing, the focus is often on functional materials – meaning materials that have their own intrinsic properties, such as semiconductors or piezoelectric generators – being combined in complex geometries, which is outside the scope of what can be achieved at home.

However the crisis has certainly shown the danger of gaunt supply chains stretched over thousands of miles, and localised in one, or a small number of countries. It may be that in future we will see industry attempt to reorganise itself around more localised supply hubs, and therefore build more resilience into supply chains.

Lend your support

If you would like to support Tony and Lyn Thompson, here is a link to their JustGiving page.

To assist their organising group, Print for Victory, click here

And if you would like to lend your aid to 3D Crowd UK, click here