My first print

Thingiverse.com is truly a universe of objects in all shapes and sizes. So when I was tasked with the freedom of choosing any object to 3D print, opportunities were endless. Luckily, I was presented with a constraint: make an “impossible object”. The word “impossible” in this context is used to describe an object that cannot be easily produced in one time using any other method of production besides 3D printing.

After browsing on thingiverse for a while I came upon this link that included a 3D printable fidget-spinner design. Being a bit overwhelmed by the world of 3D printing , I was reluctant to believe that it would actually work and becoming a spinning object. However, I decided to give it a try. 30 minutes later I had a fully functional fidget spinner in my hand, (IMG_5930) and the promising possibilities of 3D printing started to dawn on me.

The journey to consistent production

I was very happy to see that it worked! Little did I realize that the real challenges were still to come… When I tried to reproduce the same print on the Prusa i3 printer that utilizes fused filament fabrication (FFF), the fidget spinner successfully printed. However, the bearings did not spin. It is exactly those bearings that make the fidget spinner qualify as an “impossible object” which makes them all the more crucial (besides the fact that they put the “spinner” in fidget spinner. When I tried to print the fidget spinner again, on a different Prusa i3, it came out even more deteriorated.

After another try and even worse results I must admit that I felt a little demotivated. But once I figured out that it was the most likely a printer failure, my hope was revived. I moved my print to another Prusa i3. This time I thought I might as well print two fidget spinners at the same time. I needed 3 examples of this type of printing anyways. After a bit of a longer wait, because the FFF printing time approximately doubles as you double the amount of objects you print, I was disappointed to find out that the bearings had fused to the fidget spinner. I was faced with a decision: do I keep trying to print this fidget spinner or do I try to find another object?

Hoping that my first print wasn’t just beginner’s luck, I decided to try printing the fidget spinner one more time by it self. And “lo and behold” it worked. So I came to the conclusion that my fidget spinners only print successfully if I print them one by one.

USing a different printing technique

Now I only had to print some more fidget spinners using a different technique. I decided to go with stereolithography (SLA). During my first try, the print failed and I was left empty handed. That time, I tried to print the fidget spinner at an angle of about 45 degrees. Then, I decided to print it at no angle, meaning that the orientation of the fidget spinner was parallel to that of the printing bed. This also failed. Finally, I tried printing them at a smaller angle than 45 degrees. I also manually added extra supports to the automated supports that the printer’s slicing software already created. The result: the fidget spinner printed at least partially, but it still failed.

Before giving up on the SLA technique, I switched to a different SLA printer located in the Wet Lab (formlabs). Contrary to the SLA printer in the maker bar (Prusa SL1S), this printer’s slicing software decides the optimal rotation of the object for you. I was surprised when I saw that it suggested to print the spinner at a 90 degrees angle to the printing bed. I figured giving it a try wouldn’t hurt. Anyways, I was very surprised when the print came out successfully.

Conclusion

So, the story has a happy ending. Even though the SLA produced fidget spinners cannot move due to fused bearings, this is a know problem for SLA printing and is part of the learning trajectory. I’m glad that I was able to make fully functioning fidget spinners in a reasonably quick time. Furthermore, it was fun to observe other people interact with my fidget spinner. Many people were surprised to learn that the bearings were able to be printed in one go. Perhaps I could make a business out of this 😉

Cost analysis

For the first production method (FFF), each spinner cost $0.11 at 5.37 grams per spinner which took around 40 minutes to print. This would amount to $0.33 for 3 fidget spinners. Because I spent over 6 hours trying to figure out what the ideal circumstances for these prints were. Labor costs would definitely be the most expensive part of this project. At a minimum wage of $7.25 per/hour this would amount to $43.5.

For the second production method (SLA), each spinner cost $1.44 at 8.51 mL per spinner, which took about 3 hours to print. Again labor costs would have been the biggest expense, because it took another 6 hours to figure out how to successfully print a fidget spinner with SLA, this would have added $43.5 to the picture.