For this assignment we were supposed to choose a CAD file that could only be produced using 3d printing and make it. I spent a long time choosing a file because I wanted something that would print in place / would print assembled, had complex internal geometry, and did something (like had a mechanical movement). I finally settled on the “Preassembled Spherical Geneva Drive” I found on thingiverse:

I liked that it displayed a mechanical movement so the second I saw it and that it was all preassembled I chose it. Also it was pretty much the perfect size to begin with (~3 in) so I was all ready to go. The next day I went into the OEDK and got in the queue. Carlos helped me upload the file and he suggested using the Objet printer. I was behind a 22 hr project (that only had a few hours left) and then one other project and it estimated my project would take about 5 hours so I left right after I got in line and came back once while it was printing to see how it worked:

(You can’t really see what’s happening in this but it was impossible to take a good picture)

And then I came back again when it was all done. At first the drive looked super cool and it didn’t move at all (because of the supports) so I started cleaning it out and such which got plastic pieces everywhere:

And then I might have gotten a little too forceful with it (literally 5 minutes into cleaning it I got impatient and tried waayyyy too hard to push the handle) and I kind of broke it:

At this point I was real sad. I figured it probably wasn’t a great idea to waste the oedk’s resources and print a whole new part and it would take a bunch more time and all the senior design groups are using the 3d printers right now so I just super glued it back together:

And it worked great! You can see the super glue line across the sphere though which drives me crazy, but I didn’t want to paint it because the paint would rub off as the parts touch each other, so I’m stuck with it as is. I also wound up sanding the side of the glued piece a little bit because it had a little notch (where the peg driver was printed next to the slot). The sanding made it run much smoother.

A comparable part could be made using methods other than 3d printing, however you could never make this pre assembled using anything other than 3d printing and you would have to alter the design of several parts (like the handle and the sphere base) to make it not using 3d printing.