Printing our way of trouble – experience in making Covid-19 shields for 3dcrowduk from April 2020

I have recently been printing the excellent PRUSA RC3 frames for 3Dcrowduk, a a non-profit volunteer group making face shields for the NHS and Care Homes in the UK, to help address the appalling shortage of good PPE equipment nursing staff have been suffering.

Prusa’s design went through several design changes and releases before freezing on a particular version for regulatory and certification reasons. 3dcrowduk had to spend a significant amount of time and money to obtain CE in the UK before being accepted as a UK supplier the NHS even thought this was a charitable effort.

Despite being a stopgap technology 3D printing has shone in responding quickly to a crisis in mobilising over 8000 people to help out. The emphasis was to get protection out to people quickly as possible as something was better than nothing.

It struck me there is much to learn from the experience for 3D printing. I plan to summarise these later on, watch this space.

Please support 3dcowduk anyway you can:-

Follow 3dcrowduk here:

Find Prusa’s RC3 designs here

What ‘gets my goat’ about 3D printing?

It’s not the hyped expectations: “It took 6 hours just to print that small thing?!”

It’s not the overnight prints that mysteriously fail overnight.

It’s not the frustration of finding your perfect design isn’t perfect and needs changes for tolerance, weird lopsidedness or simply gravity.

What ‘gets my goat’ about 3D printing is this:

People think it’s just a toy!

A toy! It makes my grind my teeth.

3D printing is not a toy! A serious business that serious businesses invest in.

Think Construction and Architecture (WinSun).

Think Aerospace ( Airbus Industries).

Think Space (Nasa).

But what if it was just a toy? Just suppose, eh?

Now there’s nothing against toys. I liked them a lot as a youngster. They often work as simplified versions of the real thing. With the same principles. What you learn with a toy hammer you can apply with a real hammer, thumbs included.

Take gunpowder. A great Chinese invention that was initially used as fireworks, toys in other words. Yet it went on to become a key part of medieval warfare and led to advancements in casting and metallurgy. Not at toy now.

Take the steam engine. Invented in the 1st century AD and treated as toy novelty until the 17th Century. Not at toy now.

Take the laser. Originally considered the “solution looking for a problem”, a perfect toy. Yet now we find it cropping up all over the place from disc players, fibre optics, to surgical instruments. Not at toy now.

No technology is an island, it mixes, merges and intertwines with other scientific developments and its usage grows accordingly. This is happening right now with 3D printing.

So please, I ask you, don’t deride 3D printing as a mere toy. Despite its limitations it is a great and versatile technology and will find growing use in medicine, robotics, and many other fields as well.

Is there something that ‘gets your goat’ too? I wonder what it might be…

The springs! The wretched springs

I like the speed and simplicity of the Fisher Delta but do feel the odd corner was cut with the kit supplied by RepRapPro.

After some frustration and wasted time with the auto leveling playing up (where the bed switches were open circuit in one corner or the other) I found that the three springs underneath the Print bed were so weak as to have bent and distorted. A quick fix was to replace them, however sourcing these proved tricky until I chanced on a Hilka 200 piece assortment. Quite what to do with the remaining 197 springs will become apparent in time I’m sure.

The original springs

The original springs

The new springs

The new springs

Fisher Delta 3D printer – power switch mod

The power supply for the Fisher Delta 3D printer is made using a 19V power brick, which is okay except that the mains switch is too far away to kill the power quickly in an emergency – yes one of the endstop cables popped off and the printer tried to head crash on homing.

As I result we made the following modifications to add a switch into the low voltage supply:-

  1. Drill a mounting hole in the acrylic side panel for a small mains rated power switch and pop it in place.
  2. Cut the +ve internal 19v cable.
  3. Using automotive crimp connectors add an extra length of wire to reach the switch. This connect the power supply 19v+  from the socket to the switch.
  4. Lastly add another  short piece of cable to connect from the other terminal of the switch to the cut section  end of original cable going to the Duet board of the Fisher.

This means its easy to power off the Printer using a switch instead of yanking the power cable out or lunging for the mains switch round the back.

This modification won’t of course control the mains power going into the power supply brick of the printer as this is unaffected by the change.

Fisher Delta 3D printer & RepRapPro

We’re going to put a few notes out following a build of the Fisher Delta Beta 3D printer from RepRapPro. Sadly they have announced recently they are withdrawing from the 3D printer market, see “to focus on other activities”, which is a bitter blow from a company with Adrian Bowyer as one of the directors. On  the plus side the open source designs and instructions are still available form the site.

The wee beasty looks like this and was available as a self build kit:-


What is it about 3D printing that so captivates people?

Is it the wonder of watching 3D print progress? The fascination of seeing each layer build one upon one the other as a design goes from thought to reality. There is nothing quite like watching a design came to life: Layer by layer slowly building up upon itself with the printhead leaping from one section to another. As it grows it leaves areas filled with a honeycomb pattern inside, soon to be hidden and only glimpsed in the making . It is as mesmerising to watch all this unfold as it can be to stare into the flicker of the candlelight or a hearth fire.

But what is else is there once the novelty has worn off?

I can clearly remember on a summers day during one of those seemingly idle summer holidays wondering what it might be like to have my own mini world to play with. At the time this was an unreachable goal. Yet the idea was captivating And drew Me towards the imaginary worlds of science fiction.
As an adult is there a more tangible way in which we can act on these kind of creative impulses? I believe there is.
By designing your own objects you are free to think in three dimensions and to experiment with what is possible to create.

In doing so the gives you a tremendous feeling of freedom to do whatever takes your fancy to extend here, shrink there, add and subtract gives you a feeling of empowerment and total control over the design in front of you. It can be intoxicating. You could design a totally preposterous multi turreted castle with drawbridge upside out or inside out for that matter. You decide what is good without even the restriction of gravity to hold you back. Of course you may not create a design that is considered useful or practical by others but that may not be the point. It is your design. You decide what is and what will go where. It is also possible to follow utilitarian rules and generate your design to close engineering requirements which follow the best design principles for stable and consistent shape. It is entirely up to you what you do and whether you meet any external requirements. You are also free to design an unprintable design!