Introduction
For the impossible 3D objects homework assignment in ENGI 210, I used FDM (Fused deposition modeling) and SLA (Stereo Lithography) 3D printers to make my impossible 3D models, however, I only ended up using the FDM models printed using the Bambus in the OEDK for my final prints. Because I have had some experience with 3D printers, using them for robotics in high school, in ENGI 120/200, and at home, I followed the proficient level instructions because I wanted to learn more about 3D printing so that I can become more proficeient. In this project I made a variety of different prints, and post processed them as best I could using the tools available in the OEDK.
The Process
Design
After searching online for some inspiration for different objects I began the process of making the 3D objects using solid works for an invisible support illusion box and then added a spiraling design to it so that it would have a unique aspect compared to the previous designs I had seen online. It took me some time to complete the CAD model, but I was happy with how it turned out and was ready to try and print it using the resin SLA printers at the OEDK, since I wanted to learn how to use those. I also wanted to attempt to make the Vernoi ball that had been discussed in class for a bit. To do this I had to use Blender, but this did not take too long and the final stl turned out nicely.
CAD Process Steps
Final CAD for 1st Idea
Final CAD for 2nd Idea
Fabrication (SLA Printing)
I began printing the illusion spiral box on the OEDK formulabs resin printers, assuming that the print would be too precise for the FDM printers we have at the OEDK. The design did have a LOT of supports, but from advice I received the supports would be able to be removed somewhat easily since I used the flexible resin as opposed to the clear resin. After around a 6 hour print on the formlab, I had to remove it and let it sit under UV light for 30 minutes to set. After this I had to immerse it in an alcohol solvent to let clean so that it would be safe to touch afterwards.
Spiral Box model in Bambu (Left) and after SLA print (Right)
Unfortunately as you can see in the finished SLA print image, there were a large amount of supports and the flexibleness of the supports made it extremely difficult to remove using some of the common OEDK tools. Because of this I had to pivot in terms of design choice. However the print material was very flexible and the main model printed well, I would just need to learn how to use a different post processing technique to clean this model up.
Fabrication (FDM Printing)
After pivoting to using FDM printing, I decided to try some of the other designs I had considered. This included the Vernoi ball, a spiral illusion deign, and a simpler version of the spiral illusion box that I removed the spirals from. I printed various iterations of these at designed and scaled models and eventually settled on printing settings that worked after attempts with no supports, auto supports, and tree supports. In the end I had to adjust the settings to create a manual tree support setting that seemed to work well.
Initial Vernoi Ball tests (Left) and initial tests without supports (Right)
Final Print Settings (Sorry for the image quality)
Final Product
The final prints turned out nicely after printing overnight with the three different options I had in case one broke or I liked another design more for the final gumballs. Post processing took a long time for the Vernoi balls because the supports interwove inside the balls making it difficult to remove the inside supports. The tall spirals took a medium amount of time (3 minutes each) since you had to remove the supports off of the spiral which was difficult. The illusion boxes were fast to post process as they were only columns. During post processing I had to be very careful not to break the models (especially the Vernoi balls) leaving them very fragile, so users of the gumboils will have to keep that into account when using.
Final prints (Left have been post processed, supports removed)(Right has not)
Final Product (Including the two iterations of finger casting)
Reflection
This project helped me understand the basics of SLA printing, more about modeling in Blender, more about how to adjust manual supports, and post-processing. If I were to repeat this project, I would choose a simpler design for my spiral illusion so that the formulas printer would not have to use a large amount of supports to print. I would also refine more of the formulas printer settings to make the supports cleaner and possibly used a different type of resin that would make the supports more easy to remove. I would have also refined the support settings I used for the final prints on the Bambus earlier than I initially did because I tried to print them without supports entirely at first.
Materials Used
Print Details for Final Print
120 grams PLA ($8.40)
8 grams Resin ($1.60)
Bambu Rental Time (16 hours) ($24)
Formlabs Resin Printer Rental Time (6 hours) ($24.00)
Blender/Solidworks License Rental (2 hours) ($10.00)(Solidworks is free)
Total ($68.00)
