Hello family, friends, prototype lovers,
It’s been a while since my last post. Almost an entire month! A lot has happened since then. You know.. problem sets, classes, traveling to Ecuador, Beer Bike… the usual. While the break has been nice, it does feel good to be back at the OEDK making cool stuff 🙂
This week the class assignment was to 3D print an “impossible” object. This was defined as an object that would be manufactured using 3D printing only due to complex geometries, moving parts, locking components, etc. I decided to browse Thingiverse for pieces that were also optical illusions. I finally settled on a pinwheel keychain. Though this object could be manufactured with other processes, 3D printing is the most reasonable due to the small size of the object (especially the tolerances for the center holes and axel). Also, plastic on plastic is a much smoother rotation than wood on wood.
3D printing is a fairly easy manufacturing process. However, I hadn’t printed anything since last summer, so I knew I was going to have to do several iterations of the object. I started one print on one of the FDM machines and enlisted the help of a lab tech to start another on the Objet. The FDM printer finished my piece in under 30 mins, which meant fixing any mistakes wasn’t too frustrating.
Components for pinwheel: two disks and support with axle
Because I had previously had issues with prints adhering to the FDM printer beds, I decided to support all my prints with a raft. Yet, I soon realized that the raft left an ugly, textured surface and the prints could adhere well on their own. Eliminating a raft greatly decreased the amount of post-processing needed.
Left: pinwheel printed with raft
Right: pinwheel assembled without raft
The pinwheel printed on the FDM turned out well, even though the resolution was not the best. It turned smoothly and the support were easy to remove. Even so, the Objet was objectively the better printed. After an hour of printing and a few minutes of using the water jet to remove support, I was extremely happy with the result.
Pinwheel printed on the Objet
I have to admit, the above picture features my second print from the Objet. My first print was equally as beautiful but was scaled wrong so the discs did not fit on the axle. In a way, this is a blessing in disguise because I can now make an extra pinwheel for myself! 😉
