Having never really 3-D printed something on my own, I was more than excited to begin this project!
Selecting an Impossible Object
For this project, we were first tasked with finding an impossible object on Thingiverse to download and 3-D print. As scrolled through the images on Thingiverse, I was mesmerized at many of the objects that people had 3-D printed in the past. At first glance, I wanted to print the heart gears which seemed really interesting.
3D Printed Moving Heart Gear
However, because of the number of moving parts it had, I continued my search for an impossible object. Soon enough, I landed on an ornament. Due to the geometry which appeared to look like an optical illusion making it an impossible object, I committed to this design and proceeded to the 3D printers.
3-D Printed Ornaments
3-D Printing Time!
For my first 3-D print I decided to print my ornament as it was given in the download files and did not change any of the scale. I used the PLA 3-D Prusa printer and examined to see if supports were necessary on my ornament. After about 6 hours, my ornament was complete. At first look, I noticed that supports were not actually necessary and instead made it difficult for me to remove them from my ornament.
Printing with Supports
As I had expected, the ornament was also bigger than what I had wanted and would not fit in the small containers that were given to us. So I started to scale the image down.
Ornament was too big
After adjusting the height and removing the supports, I printed again. This time, it took 45 minutes for it to print. However, this time, my ornament was smaller than what I had wanted. Therefore, I adjusted the size again and this time, I was able to get my ornaments to the optical dimensions: not too big, not too small, but just right. Other than removing the raft, 3-D printing using the PLA printer did not require as much post-processing as the SLA printers did.
3-D Printing my Small Ornament via FDM using PLA
For four of my ornaments, I experimented with the different PLA printers to print my ornament in different colors. For my last ornament, I used the Prusa SL1S 3-D printer. I filled it with orange resin and waited the next 2 hours for it to print my ornament. Compared to the PLA printers, it was interesting to see the difference in the way both printers 3-D printed my ornaments: SLA used a laser to cure liquid resin in hardened layers whereas PLA melted the thermoplastic filament material and applied the plastic layer by layer to a build platform 3-D Printing using SLA.
After 3-D printing via SLA, I placed my ornament into a water bath for 10 minutes and then placed it in the curing for 30 minutes. Once this was completed, I removed the raft from the bottom and the single support from the center of the ornament. Compared to the FDM, I really like the smooth finished appearance of the resin.
3-D Printing Complete
If I were to do this again, I would select an impossible object that has moving parts and experiment with different printers. I observed that the Prusa SL1S 3-D printer caused some of the impossible objects to fuse together.
Impossible object COST ANALYSIS
Below, I have provided a breakdown of the cost estimate for my 3-D printed impossible object.
It is assumed that the machines used ( Prusa SL1S 3-D printer and the PLA 3-D Prusa printer) can all be rented at facilities like the MakerBarn [1]: $40/730 hours X 48 hours = $2.63 (assuming machines are rented for 2 days).
- Machine Cost: $2.63
Labor Time
6 hours hours Thursday
5 hours Wednesday
Total hours: 11 hours
Overall Labor Cost [2]: $7.25/hr X 11 hours = $79.75
TOTAL COST OF impossible object: $82.38
[1] https://www.themakerbarn.org/memberships/ [2] https://www.minimum-wage.org/texas#:~:text=The%20Texas%20minimum%20wage%20was,Federal%20Minimum%20Wage%20by%20reference
