Week 4: 3D Printing and Scanning!

When brainstorming ideas for what to cut something additive on the 3D printer, I was stuck on what additive really meant. A TA explained that it was like the zipper on my laptop case- something that’s not impossible, but really hard to cut using subtractive cutting machines like a mill without breaking the pieces afterwards and putting them back together.

I then realized that additive really means interconnected pieces that make a larger system- then I thought of the idea of chain mail, so a chain of rings. I wanted to make a choker necklace made of chained together rings so I designed it in blender.

I exported my design as an .stl and opened it on the uprint monitor:

I realized two things at this point. One, my design was not flattened, it was a ‘blob’ of sorts which required a ton of unnecessary support material. The blob required 0.72 cubic inches of model material and 1.73 cubic inches of support material and a print time of 5 hours, 58 minutes. Two, a necklace of around 18-20 inches in circumference was unrealistic and would take around 10 hours, which given that there are other people that want to use the 3D printer, probably isn’t a good idea. So I decided to make a bracelet instead.

To fix the ‘blob’ issue, I used solidworks instead of blender to make a more flattened, square shaped necklace. When I viewed the design on the uprint monitor, the model material was 2.83 cubic inches and the support material was 2.85 cubic inches, and a print time of 9 hours, 27 minutes- again super unrealistic. I then reduced the scaling by about 70% to switch from a necklace to a bracelet, which resulted in 0.13 cubic inches of model material and 0.32 cubic inches of support material, and a print time of 1 hour, 17 minutes, which was totally doable.

The print design looked good so I began the print job and watched the machine start to pour out the plastic layers- it was really satisfying to watch to machine lay the plastic down. More therapeutic than soldering for me at least.

This is what the inside of the uprint looks like:

The uprint is doing it’s job here, heating the PLA and laying it down.

A quick aside- while waiting for my print job to finish, I wanted to do some separate ring testing and use the prusa just for fun.

Specifically, I was trying to figure out how much support was actually going to be used when placing rings horizontally vs vertically. Here are two rings modeled in the prusa slicer software.

I was also able to view this slice by slice which was helpful in understanding where the objects need support for the printer to accurately print them. With the vertical ring, there was support in the center of the ring but I took it out manually just to see if it would still work, even though it’s in an unstable position.

Here’s what happened:

Basically, the vertical ring wasn’t adhered well enough to the support so it moved around during the print and caused the layers to shift around. A simple solution was the glue the vertical ring down to the surface- the results were much better.

Back to the original bracelet. The print job finished so I pulled it out and peeled the backing off the bracelet.

Then I placed it in the ecoworks solution to dissolve the support material.

I let it dissolve for about an hour and then pulled it out and rinsed it with water.

Here it is on my wrist! It fit really well but I left the two end rings unconnected so that I could take it on and off. I’m likely going to tie the ends together around my wrist with a string.

The next part of the assignment was to scan something.

At first I was ambitious and I wanted to scan my electric scooter. I didn’t realize that an object-less background was necessary for the Sense scanner to collect good data and my scooter was a little large for the space I was working in.

It’s clear that the scanner is barely detecting the scooter in relation to it’s background.

I then tried scanning a soldering iron on a table- it worked well but lost tracking once my scanner was 180 degrees around and there was a lot more background noise.

I put the soldering iron on the floor and realized the ground had a much worse background than other objects, because the floors in EDS are supposed to hide flaws so there’s a complex pattern.

Finally, I found the sweet spot- the soldering iron in the center of the wooden table. The scanner got a really good 3D model of it overall, but missed part of the handle because it had a hard time detecting the wire attached to the iron.

Here’s the final 3D model from several different angles.

We started using 3D printers and scanners this week, so before doing any of the work shown above, as always, we characterized the design rules for a 3D printer.

To do this, my team and I printed a number of things to demonstrate what “additive” vs “subtractive” means, what infill looks like, what supported and unsupported overhangs look like, among several other types of objects. We were given stl’s for the following designs- we used the uprint 3D printer and the Prusa, and divided and conquered the prints.

supports: overhang This shows overhangs that were printed with supports. We didn’t have any problems when using supports.

clearance: This shows the clearance of certain sized rings around a cyclinder, allowing some to turn and some not.

unsupported: angle This is showing different angles of overhangs without using support material. It worked well at this size but it’s likely that it might not work with larger sizes.

free overhang This shows unsupported overhangs- we didn’t use support for this one and it turned out well but again at larger sizes it might not work.

anchored overhang First, we printed the free overhang stl using the uprint printer. We scaled it down to save time and material.

We wanted to try printing without support material, and it worked well. We used the 3D wox printer because we could select ‘no supports’ and print it freely.

Here’s the two of them next to each other. We scaled the first one down but did the second one at 1.0x.

wall thickness This demonstrates different wall thicknesses- this is subtractive so it could be cut with a mill.

dimensions We scaled this box down, it shows dimensions of two different boxes- machine does a great job laying down plastic to make perfect squares.

anisotropy This shows a 90 degree angle making the shape of an L. It’s a fairly small design so the upper part of the L stayed stable but if it was a bigger design it’s possible the L would collapse without supports.

surface finish This is showing the outside and inside of a sphere and what the finish looks like. It almost looks like a perfect sphere- the machine is very accurate.

infill This shows a box with the number fifteen cut- it could also be cut with a mill- it’s not additive.