Introduction

This week’s project was to make an impossible object using 3D printing. The constraints were to make five objects using two printing methods that maximize the space of the gumball capsule the objects were to live in. I was looking forward to learning SLA printing and getting a cool, impossible part out of the process–in this blog we’ll see if my hopes were fulfilled.

Step 1: Selecting a Print

I went to Thingiverse and started perusing their selection of impossible objects, but none of them stood out so I started looking at past projects for inspiration. I found an egg with a cool pattern in it, so I uploaded the stl to the slicer and scaled it based on the measurement I took of the capsule. I took a ratio of the capsule length to the size of the part in the slicer. I thought to myself, “Wow that was an easy project” then saw that it would’ve taken over half a day to print all five of the parts–much too long of a process for such a relatively small part.

I had to go back to past projects for more inspiration, which I found when I saw the icosahedron in a box. I always enjoyed playing with internal geometry prints so this would still fulfill my hope of making a cool part.

 

Step 2: Printing!

After finally selected the part I messed around with the scaling in a similar way to before, and made multiple prints on the Prusas to test sizing and print quality. As you can see in the image below, the size in the white PLA fit the capsule best. The only complaint I have with the way Prusa prints is that the supports are extremely difficult to remove without risking the object breaking. What could improve this is making the object’s wall thickness larger.

I then used the same scaling properties on the Bambu [because the SLA printers weren’t working 🙁 ]. The Bambu has an option to print with tree supports which I found so much easier to remove. The only gripe I’d have with them is that the print quality for the overhang of the box is a bit warped, so it did not come out as well as the Prusa despite being objectively a better printer. Additionally, it seems that either the printer bed or filament had imperfections which seeped into the print.

Step 3: Post Processing

If you look closely at the pictures directly after printing and removal of the supports, there are rough edges on the prints. I tried to rectify this by using sand a high grit sand paper to smooth the sides and decrease blemishes caused by glue on the print bed (not sure why it was there, the Bambu usually prints great without glue).

My final thoughts…

All-in-all I fulfilled one of my hopes: to make a cool, impossible part. I will most likely learn how to do SLA printing sometime in the near future, but for this project I do not think solely using FDM heavily affected the outcome of the print. I have only ever made parts for engineering purposes, so now I look forward to making less serious, silly parts in the future!

 <–Clean work space

Cost Analysis

PLA: $0.12 each, 5 object total = $0.60

Labor: $15 per hour for 2hrs

Total: $30.60