I started off this project attempting to fabricate a small scale version of a Gyro Cube. See the link for a great 3D-view as well as the part files: https://www.thingiverse.com/thing:237421?ref=makexyz

I was able to print this piece with some success, but the major challenge was removing the support. The first time I printed, a lab assistant post-processed my part with all the support on it which left my part very brittle and led to it’s eventual shattering as I attempted to remove the support.

 

On the second go-round, I made an obnoxiously large sign to make people aware that they should not process my part. This allowed me to remove support while the part was more flexible and the body would break with less creep/cracking (left). I did this by first putting the finished print through the Form Wash for 20 minutes to remove the excess filament. Then, using diagonal cutters, I carefully trimmed away the supports from the piece. After completing this step, I washed the piece for 5 more minutes and then cured it in the UV chamber for 20 minutes at 60 degrees Celcius.

I still had a few cracks in the final product (right), however, they were few enough that a small coat of superglue bridged the gap fairly well. A warning: removing the support in a very careful way took me approximately 5 hours due to the high plausibility of the support break to crack into the part.

When I selected the Gyro Cube as my 3D printing part, I made the assumption that the OEDK had a working FDM printer which used dissolvable support. But, to my frustration, none of those were functional. After some brief contemplation and a trying attempt to fix the Ultimaker, I decided to change objects to something which I knew would successfully print on an FDM printer without dissolvable support. The one option that possibly could have saved this concern was to print the object in a stronger material or with reinforcement so that it would sustain the necessary actions to tear away the support, and my inclination was to attempt to use the Markforged. However, upon my initial attempt to slice the part with reinforced walls, I learned that the layers of my part were too thin and small to successfully deposit a layer of carbon fiber. At this point, I resolved to print a different object.

I eventually landed on a chain mail design which was simple, but still a good fidgeting piece: https://www.thingiverse.com/thing:50660/files. In order to make the part a bit more unique, I decided to print the piece using the flexible, fabric-like filament called TPU.

For this object prints, I scaled the part size down by a factor of 0.65 in order to ensure that the final part would fit reasonably into the plastic containers.

 

When the prints finished, the tolerance between the links proved to be much less than it appeared in the printer software previews. 

For the TPU, this tolerance error was easily solved as the extrusion paths lended themselves to just pull apart the edges that gently fused together (the more flexible material property helped too). 

However, the SLA part ‘globbed’ and formed a solid blob at the points which were supposed to be distinct elements of the chain. I attempted to separate the rings using the new ultrasonic cutter the OEDK purchased, but unfortunately, the part was not geometrically designed to account for this type of issue.

As a result of these two unfortunate events in this design challenge, I decided to submit the TPU chain mail along with the successful print of the Gyro Cube. I also included set to the side the unsuccessful prints for the first Gyro Cube as well as the SLA chain mail piece.

Evaluating the cost:

• Design Cost
  • Free! At least to the public. Thingiverse did all the design work.
• Consumable Cost
  • The amount of resin consumed for just the chain mail SLA print was approximately 10mL
  • Resin costs about $50/L –> $0.50
  • The amount of TPU used was 34g and corresponds to about $0.68 of filament consumption for all the TPU pieces put together
• Machine Time
  • A makerspace membership costs $60/mo
  • This machine time probably correlates to 1/12 of monthly usage for an average member ($5)
  • The successful/submitted prints consumed approximately 1.5 hr on the Form 2 and 12.5 hr on a Prusa loaded with TPU

Total Expense: $6 ($8 if I included failed prints)