Before beginning this project, I was looking forward to the opportunity to gain more experience with the 3D printers at the OEDK. Despite this course being my 3rd ENGI class so far, I had yet to gain enough confidence using the printers to feel generally comfortable in my ability to execute and troubleshoot a project. Consequently, there were many hiccups with my process, but I do now feel increasingly more certain in my understanding of how the printers work and what steps I need to take to produce a good print.
Picking My Object & Scaling It
For my impossible object, I chose to 3D print a lizard from Thingiverse which I have linked here. However, since the shape seemed a bit large, had a long print time, and I feared it would not fit in the gumball capsule, I went ahead and scaled it to 50%. I then completed a test print on the FDM printers to determine if this scale factor would be sufficient. Though the lizard from this print was small enough to fit in the gumball capsule, I accidentally managed to snap one of the links in the middle of its body while peeling off its brim. This caused the entire piece to split in half. I suspected that this scale was potentially too small resulting in links with diameters that were too narrow and easy to break. So, I went ahead and settled on a scale factor of 75% since this size would still fit in the gumball capsule but still have a relatively short print time on the FDM printers.
FDM Printing
Since this project was due at the end of the semester, many of the FDM printers were busy printing 15-24 hour prints at a time. To eventually finish my printing 4 of my 5 impossible objects on them, I had to return to the OEDK multiple times over the course of a few days since there would not be an available printer for me to use many times.
Generally, the set up and sending of prints to the 3D printers was not a complicated process. However, I did run into some issues at times with the nozzles getting clogged, so I would need to clear the bed and restart the print.
Once my lizards were printed, I did have some problems peeling off the brim I had added to help with plate adhesion. Since the lizards’ fingers were so small, they ended up peeling off along with the brim instead of staying stuck to their hands. In some cases, the lizards’ entire limbs were also peeled off during my process of removing the brim. Admittedly, I should have reprinted more iterations of my objects that would have allowed me to add supports that do not peel off details of the animal along with it. But, I also recognized that other users at the OEDK were waiting on 3D printers to become available, so I decided to just stick with my current 4 lizards to help reduce the traffic with the printers. In the end, I ended up removing all of the limbs from the lizards so that they would all look consistent resulting in my final impossible objects being some kind of mystery reptile that is a cross between a lizard and a snake.
My 3D printed lizards with missing fingers:
Using the Resin Printers
I definitely relied on the lab assistants and some classmates to figure out how to prepare my files and operate the resin printers. But overall, the process was pretty straightforward once I had gotten a quick run through. I did manage to accidentally forget to resize my lizard before sending it to the resin printer resulting in a clear size difference between my FDM printed pieces and my resin printed piece. Admittedly though, having my impossible objects be the same size was not a criteria on the assignment, so I kind of enjoyed seeing the differences in detail and size between the two materials and printing methods.
As for my resin printed piece, I definitely underestimated how much longer a print on the resin printer would take compared to an FDM printer. Consequently, I wish I had started my print a lot earlier since I had to stay back in the OEDK to complete the resin printing process though I had completed my 4 FDM prints at the time. This would have also allowed me to experiment more with additional printing iterations and increase my confidence with the machine’s operations.
Cost Analysis
- successful FDM printed parts = $0.05/piece * 4 pieces = $0.20
- failed FDM parts = $0.05/piece * 2 pieces = $0.10
- successful resin printed part = $199/1000mL * 7.64mL used = $1.52
- labor = $20/hour * 10 hours = $200
- *excludes cost for communal tools and machines
TOTAL = $201.82
