Week 4

This week we covered 3D printing and scanning. For the group assignment, I teamed up with some friends to re-attempt a test of the maximum overhang angle the Prusa machines can handle without supports. For my individual assignment I designed and printed two chain links.

I also tried to 3D scan my hand, and a flower.

3D printing and scanning

This week I 3D printed chain links and 3D scanned my hand and some flowers. I will first go over the 3D printing workflow, and then the 3D scanning stuff.

Designing & 3D printing chain links

First, I designed two simple chain links in Fusion360. To do this, I made a sketch of a slot to get the general shape of the chain link. Then, I created a circle perpendicular to that path, and used the Sweep tool to sweep the circle around the path to produce a single link. I copy-pasted that link and arranged it so that it intersected the middle of the other link. Here was my final model in Fusion:

Next, I exported my .stl file and imported it into the Prusa slicer. After selecting my machine and configuring the materials and adding supports I was able to export a .bgcode file for printing.

I learned how to load filament into the Prusa printer and loaded in this nice silver filament to match my chain. Here’s a photo of the Prusa hard at work:

The whole thing took around half an hour. Here’s how it came out:

I used some pliers and my brute strength to remove the supports:

And, the final product! It is an incredibly satisfying fidget toy, and I am overall happy with how it turned out. There are a few patches of unnevenness in the print, but it’s not too serious. Baby’s first 3D print, in the books! :)

3D scanning with Polycam

I used the app Polycam to 3D scan things.

At first, I wanted to scan my own hand so I could make a laptop stand for my desk in the shape of my hands. Polycam’s interface automatically snaps a series of photos which are fed into its model. I tried to hold my hand very still while rotating my phone around it, and I ended up with this mesh:

However, this didn’t turn out so well, as I was unable to get good shots of the bottom of my hand. The mesh does not capture anything other than the top surface of my hand – here is a view of the bottom of the mesh.

I decided to give up on scanning my own hand, as I figured it would be too hard to both hold it still enough and get shots of all possible angles.

Instead I decided to try to scan a flower. After taking 100+ images, here was the resulting mesh:

I used Polycam’s 3D cropping feature to isolate just the flower from the background:

Finally, here was the result:

Characterizing overhang

This week, Ben, Yufeng, Sun, Matti and I characterized the overhang angle of the Prusa MK4S printers. I learned how to load and unload filament from a 3D printer, and how to slice a file and then run the 3D print job.