For this project, our goal was to 3d print 5 identical “impossible objects”, meaning that the objects cannot be manufactured using any other method. For mine, I chose to print a simple ball trapped within a cube, which cannot feasibly be created with other methods and is pretty simple to print. I first used thingiverse to find a STL file for the object (https://www.thingiverse.com/thing:127301). Then, I imported the STL file into 3dprinteros and scaled the cube to 30 mm so that the cube would fit into the capsules. I wanted to print everything at once so I clicked copy object and chose 4 copies. The layout looked like this:
After this, I was ready to print. I printed on a Prusa I3 MK3 and chose to use the default settings with supports and a skirt. The print was successful and took a bit less than 7 hours to finish. The print looked like this afterwards:
Next, I had to remove the supports and separate the cubes from each other. I first wiggled the balls around inside the cubes to separate the balls from the supports. Next, I took needle-nose pliers and ripped the supports out of the cubes from the circular holes generated in the supports by default. This was pretty simple and did not take very long at all, totaling about 15 minutes. In the process however, I got unlucky and part of one edge of a cube came off with the supports. I still consider the cube a success since it is still an impossible object and still is a ball trapped in a cube. I filed down the remaining nubs of the torn edge and will pretend that this was the intended product all along. Just make sure you don’t tell anyone about this; they’ll never find out.
In conclusion, this project went very smoothly and I would consider it a great success. The printers in the OEDK are finely tuned and well maintained so I did not have to worry about anything like bed height, choosing filament, or bad settings. Each ball was printed and processed *flawlessly*. The balls are sized properly to fit in their capsules.
Cost analysis:
Print cost: $1.34 – cost given from 6:43h on a Prusa I3 MK3
Labor: $20 – 1 hr at $20 per hour
Total cost: $21.34
