Project 3: 3D Printing a Top

Process
Starting out, I had no idea what I wanted to make with this project. While I have come up with a number of projects involving the laser cutter and/or wood cutting, none of them really lent themselves to the use of Fusion 360's sculpt tool. After messing around with the tool and rotational symmetry for a bit, I decided that I wanted to make a really alien-looking top. I started with a cylinder and formed it into the rough shape I wanted. Then I added lots of weird little holes into my design, using the rotational symmetry tool to make the pattern the same all the way around.

When it came to printing, I realised I had a problem—it would be very difficult to print the spindle at the top without adding in lots of support material. So I redesigned it a bit, modifying the spindle so that it was a separate part that would lock into place with a key and keyway.

Printing this resulted in a decent prototype, but with several problems. First, the print came loose from the print bed about an hour into my 3-hour print. After pausing the print, I did my best to line it up again and glue it back to the print bed, and while I was pretty close for just guessing and eyeballing it, there ended up being a very noticeable seam. Second, the top surface of the object, which I had decided to print upside-down, against the print bed, was not perfectly flat, and it ended up having some ugly extraneous material stuck to it that I couldn't clear off without destroying the print. And lastly, the spindle was too big to fit into the slot I made for it, because I hadn't compensated for the thickness of the material. After two more attempts at reprinting the spindle, I finally found a measurement that would allow it to fit snugly into the slot.

Because there were so many problems with this prototype, I decided to modify the design and print it again. This time, I went with a four-piece design, where I had the spindle, as well as an upper and lower half of the top, which could be joined afterwards by a keyed ring. On all of these interlocking parts, I made sure to compensate for material thickness using the value I determined from the prototype. Aside from a few mishaps involving the printer spewing globs of black gunk and weaving them into the print, the print went pretty well.

When assembling the four pieces together, I noticed that there was a bit of a gap between the top and bottom halves of the piece because the internal ring piece was too tall for them to be flush. I also managed to snap off the spindle when trying to attach it, so I reduced the height of the ring and printed both the ring and the spindle again.

Result
I'm pretty happy with the final form of this project. I really like the look of the translucent red PETG filament, and I like the pairing with the speckled grey PLA. I am particularly pleased with the smoothness of the edges and how well all of the little holes I made turned out. As a top, it doesn't spin super smoothly—it has a noticeable wobble every few turns—and I wonder if that might have to do with density asymmetry in the interlocking pieces, or the holes in the sides, or perhaps with the way the point of the top printed. It does spin for a while though, and it is also super satisfying to hold.

Reflection
Aside from the general annoyances of the way the sculpt tool works, and despite the time-consuming nature of 3D printing, I enjoyed this process. I had never used a 3D printer before, and this project taught me a lot about how to use them, as well as different quirks that come with the process that one needs to keep in mind with a 3D-printed project. I look forward to continuing to use 3D printers in the future!