For our 6th ENGI 210 assignment, we were tasked with creating an impossible object that could only be practically manufactured through 3D printing. We would print our object twice (once with a Makergear, once with a commercial printer) and put our objects in a gumball capsule, to be placed inside the OEDK gumball machine. An excuse to print cool objects with some of the fancy wet lab printers? Sign me up!

Because it was the end of October, I was in a spooky mood and wanted to print a spooky object. After browsing through Thingiverse for way too long, I finally settled upon a Vornoi skull as my object of choice.

 

A Voronoi diagram is a tesselating pattern produced from dividing a plane into regions based on distances of the points to specific subsets of a plane.

The odd holes in the skull are called Voronoi patterns. The intricate foldings and openings in the skull make it nearly impossible to produce with any other method besides 3D printing (imagine trying to cut all those holes precisely or mold the filaments around the eye socket!).

Our first object had to be made with one of the Makergears in the Maker Bar. Based on past experience, the Makergears are not exactly super precise and can leave behind a lot of stringy filaments instead of a clean finish. I admittedly had little faith in the Makergears. Since my skull would only be 5 cm tall, was extremely detailed, and had a giant hole in its center, I worried that my print would end up a messy, partially collapsed blob. I used a 0.1 mm layer height for higher resolution and no supports, because I had no idea how I would cleanly remove them through the tiny holes after the print was completed.

Wow. I did not expect that to turn out so well. Surprisingly enough, the figure did not collapse on itself despite the lack of supports and the lattice patterns inside the skull showed up quite distinctly!

Next, I used the Dimension for my higher fidelity print. The Objet is the best printer in the wet lab, but waterjetting all the supports out of the object at the end would be annoying, and might damage the Voronoi structure. The supports used by the Dimension are dissolvable in the wet lab’s caustic bath.

Surprisingly, the Dimension and the Makergear did not produce wildly different results. The Dimension made an object that felt slightly sturdier and had a cleaner base but didn’t look as distinct as the Makergear object (either because of the caustic bath or color of the filament). There were a few stray wisps in the object that made the Dimension print look blurrier than the Makergear.

Cost Analysis:

Makergear material: negligble

Dimension material: $13

Machining: $20/hr * 7.5 hrs  (1.5 hrs (Makergear) + 6 hrs (Dimension)) = $150

Total: $163

Quality 3D printed skulls for only ~$80/piece, coming soon to a gumball machine near you!