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


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!

Article by Leo Kelion on 3D printing on BBC Website – “CES 2012: 3D printer makers’ rival visions of future”

Todays article on the BBC Website focuses more on the novelty value of 3D printing but does mention a familiar maker for extrusion printing, Makerbot and it’s new Repligator model, see also here in TechNewsDaily.


Makerbot Dualtrusion build – Z stage

This is the Third stage we took to build Makerbot’s  Dualtrusion 3D printer.

Instructions for this stage were taken from here and here in the preparation stage.

The Y-stage is a straightforward part of the build, which forms the platform that moves the print head assemblies up and down once in place in the printer.

The very small nut and screw pack should not be confused with low profile M3x16 bolts used in the X-stage assembly:-
The low profile M3x16 bolts (silver) used in the X stage of the build:

For the motor Flange we had the moon type so the flange went on what will be the outside section.
I needed to tighten bolt heads gently with a small star headed screwdriver and then turn the nuts on the back with electronics pliers to tighten them properly:-
The instructions do not indicate which round to fit the bearings? I put them in this way round:-

Note: Don’t bother to sand the bearing holes as they may not be tight enough as it is- I notice that one way round is looser than the other so there may be an artifact of the laser cutting process on the wood composite.

The final assembly was quickly completed and looks like this:-


Makerbot Dualtrusion build – Y stage

This is the second stage we took to build Makerbot’s  Dualtrusion 3D printer.

Instructions for this stage were taken from here.

The Y-stage shuffles the X-stage component, in our case the Automated Build Platform (ABP), from left to right and back again when viewing from the front of the printer.


One is reminded once again of the ingenuity of the build, as illustrated in the way in which the drive rib has been lasercut with a series of vertical cuts spaced to math the belt teeth kept in place with a couple of small wooden clamps. No drilling, screwing, cutting, or glueing the belt here but a sure fire way to hold it in place.


Our kit had the moon stepper motor for this stage of the build.


Stepper motor in situ:
the stepper motor is only lightly bolted in and a can slide to and fro from the idlers. We ended up twisting the stepper motor cable to keep it tidy instead of tying with kapton tape but  may revert to that later.

From the other side you can see the stepper motor capstan (pulley) protruding cheerfully:
The instructions do not specify when to tighten the bolts into the stepper motor after assembly – which means the two near the edge are fouled for adjustment by one fo the rods! I had left these slightly off tight so only tightened the two further from the rod that were accessable. These may need to check after first use! The educator version of the instructions does mention this however so maybe these are better instructions to use.

Finally putting both stages together and we look like we are finally starting to make progress with the build.

The potential of 3D printing – article in todays Telegraph

Interesting article by Roger Highfield here on the potential of 3D printing in todays Telegraph!

It heralds the “next industiral revolution” and talks of “bespoke craftmanship” through increasing ubiquity of 3D printing.

Thanks Mark for letting me know of this!

Makerbot Dualtrusion build – Automated Build Platform (ABP)

At long last we have received the parts to build Makerbot’s  Dualtrusion 3D printer.

Instructions for the build are available here or ofr “educators” here! Confusing isn’t it!


There is the preparation work of popping out the laser cut wooden parts, running a damp cloth round the char left over from the laser cuts, and tidying the small nibs of wood that were holding the parts in place.

Once this has been done the first part of the build can start, it helps to separate the necessary parts out of the morass  so you don’t have to hunt and peck so much to get going.

We chose the Automated Build Platform (ABP) as our X-stage platform to print on as we expect to do a lot of printing and need the printing to keep going by itself as much as possible. The alternatives are an unheated or heated acyrilic surface, or a static heated board instead.

The instructions I used for the APB are here on the Makerbot site, as I didn’t have the aluminium plate in my kit.

The instructions ask you to sand where the belt goes but as you may not have a clue for the overall structure and the wooden parts aren’t numbered you have no indication of parts to sand or what the idler is mentioned in the build text.

For context this is where the belt goes:-
I sanded here for both parts:

Sand round holes of side pieces only slightly as it is easy to overdo – you can always sand a bit more but can’t undo – you don’t want to revert to gluing them in instead. Push in until feeling tight about 2-3mm proud the other side – if not sand more. Push gently one one side then the other to ‘rock’ the round bearing into place until the toothed rim is right up against the wood.
The reference to left and right hand side in instructions for where to install the motor not useful as orientation of the piece not established first. See below for where it goes!
Also the 8mm M2 bolts for the motor did not fit and I had to take one of the m3 to open out the thread and then run through with the m2’s using the thread cutting technique of turning clockwise then anticlockwise then clockwise repeatedly until the thread ran freely.

The motor did get in the way of one of the nuts during the final part of the build, so I shifted the whole heated platform section to overhang slightly to give enough room, as above.
The final construction completed!

Wash roller under tap and dry with microfibre cloth to remove dust that may have been attracted to the silicon rollers.

Use diamond files for speed and accuracy instead of the supplied sandpapers if you have them to hand.

Tighten the small bolts by hand and only tighten gently with the Allen keys for half a rotation or so depending on the feel.

Article on 3D printing in PCPro Magazine

This month’s PC Pro magazine has a thought provoking Article on the potential of 3D printing entitled “A licence to print anything” by Stuart Andrews. It touches on the recent Exhibition at the Victoria and Albert Museum in London which showed of prototype clothing which had been printed as well as Chairs, tables, shoes and lampshades. It is clear that the frontiers of 3D printing are being expanded as the article also refers to printing in Cement for architectural purposes, print a house anyone?