The First Physical Gridcoin - 3D Printed Plastic!

in gridcoin •  10 months ago


When I was in the consulting industry as an engineer, I built a habit of prototyping everything, to get a feel for how things look and feel way before the finished product is due. So, today I made a plastic 3D print of the old design for the 1 millionth block commemorative coin! I will walk you through the process:


This is a Stratasys Connex - a silly expensive machine sitting in the additive manufacture lab that can print everything from remote control casings to dental implants. The materials loaded were a rigid clear and a rubbery black, so for this run I used the clear compound.


This is the printer on the job while running a mid-job nozzle cleanse. It's currently spraying material from the 8 print heads into that cavity on the build floor - pretty messy! The black circle is the (almost finished) print job of the coin, which is encased in a very rigid jelly. Total build time was 68 minutes.


To remove the jelly from the print, we use a pressure washer. You can see me holding the coin in the center, and the bar in the bottom right is a windscreen wiper to wipe the water and residue off the viewing port. Cleaning up the print is pretty fast, and the fine detail is finished with a toothbrush. This is the result (5cm diameter):

The 3D model for reference (credit to @me-shell and @joshoeah):


I may coat the coin in a brass-coloured enamel or something - not sure yet. Of course, this is only a test piece and I am waiting on a community decision on the final model. However, some things I learnt along the way:

  • Some of the details on the original artwork/logo are incredibly fine. Even at this scale, the smallest details are only 0.2mm across. If the plan is to make these coins actual coin size, and to reduce the area taken up by the original art to about half, that means the details will be 0.05 mm. I don't know any manufacturing method that will cope with that nicely, so I may need to take some small modelling liberties.

  • Printing these things is smooth sailing from here on out. I could whip up 100 of these in the next few days if we wanted as the print time does not scale linearly. The build plate could easily take 60 coins in one go.

  • A uniform colour in either solid black or see through doesn't look as flash as I might like. I will enamel this and report back.

I have also done some experimenting with the CnC machine, and it will struggle with small details. The problem is that the super fine cutter tips taper to a point, and as you approach the tip the surface speed approaches zero. Therefore, it is very hard to get a nice surface finish on tiny details. I will do some experimenting. On the bright side, I did find a bunch of leftover brass bar we can use!

Image credit, in order of appearance:
Banner, @joshoeah
All photographs taken by me on my NZD$100 phone (apologies for potato quality!)


Authors get paid when people like you upvote their post.
If you enjoyed what you read here, create your account today and start earning FREE STEEM!
Sort Order:  Trending

Congrats you have been selected by the Steemvoter (SV) Guild, keep up the good work and helping make Steem great!

Note: You should receive many guild votes in an hour or so, enjoy!


Awesome! Thank you very much! =D

Wow @dutch - that machine! Only slightly jealous :)

The coin looks great, especially as a first proof! It's a shame about the detail, but I'm sure between you, me and @me-shell we can tweak the design and model to produce something that's both detailed and compatible with the limitations of the machine.

Shame to hear about the CnC - again, perhaps once we've tweaked the fine details we can get it working a little better? Can't wait to see how the print looks with an enamel finish - thank you for dedicating your time to this!


I wish it was mine! It is actually sitting idle in the lab 95% of the time, because it is too much effort to drive for the average user so they settle for the cheaper machines. On top of that, several of the print cartridges are about to go off. Good we are using it!

I agree, we can definitely make it work. The CnC machine is still very much a viable option, but we will be able to do some tests once we have the final design out. I am going to do some more experimenting with fine detail tomorrow.

There is a metal fabricator nearby who may be able to try stamp the design as a coin. I will do some exploring. May be worth testing it first before ordering 100s from a third party.


It is pretty exciting to hold something in you hand that you designed on the computer not even a week ago! 3D printers are such wonderful things.

As for the design we could simplify the art work down a little and increase the thickness at some points. It obviously wouldn't look exactly the same but most people wouldn't notice, if anything it would look better. The Artwork can defiantly not go smaller with this design at this stage. The coin however could be a tiny bit thinner to save on material which is a plus.


I'll give simplification a shot this afternoon and see how I get on. If I come up with anything I'll pass it on to @dutch for you to take a look at.

The very first physical Gridcoin! In a few years, it will be a prized collectible worth millions, so don't throw it away :)

man, i'd love to have access to a machine like that. i've only ever used a wood laser cutter (which i loved and miss greatly) but that thing looks a beast! :)

Looking Good! For a proto.

Amazing. This is a really great work, wow. This is really beautiful. I haven't seen it before. I love it very much @dutch


Thank you, I really appreciate that! =)

Who needs a metal coin or even one coated with brass, this transparent plastic/rubber is way AWESOME and super-futuristic!!! I want that one!!!


Haha it is pretty cool. Actually kind of symbolic really if you think about it: the fact there isn't actually coins involved at all

I'm looking forward to the opportunity of getting my hands on one of these!

I'm really liking the design and honestly thinking that that size looks perfect. What was the actual coin size being considered?


The size is still up for debate but it needs to be a compromise between price, manufacturing techniques for detail, design and community input. I agree though the current size is pretty good.

Thank you so very much for taking the time to do this, and, yes, I am also extremely jealous of that machine. Is it free on Saturday night, can I take it out for drinks? Will it mind that I am married?

Magical !!

I'm jealous too dutch, wish I had access to that level of kit.

Really wonderful to see a physical representation of the coin and I can't wait to see the complete result.

Thank you for keeping us up to date with the process and look forward to further updates.


Technology is a beautiful thing!