Wednesday, July 29th, 2020
Welcome back to another post about Marble Machines! I've kind of been hyperfixating on building these things and so far I've found that it's an excellent way to ignore the current turmoil going on in the world at the moment!
Today I'm just going to post some pictures of the work in progress Marble Machine 2, as well as talk about why things are designed the way they are and how it was to build this thing. Then hopefully I'll link a fun YouTube video at the end where you can spend hours watching the finished machine (because I know I'm going to spend hours watching this thing in real life).
These sections aren't really going to be in any particular order so I just hope you enjoy learning all about this new sculpture of mine!
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| View of the mostly finished sculpture |
The Frame
The sculpture frame was an important thing for this project. Not only would it provide a structural support for all the elements of the track, but it would contain everything within an enclosed space so that it didn't look like garbage (for an example of a poorly looking sculpture, see my last marble machine post here).
I decided it would be cool to build a sort of truss structure linked together with 3D printed parts, using 4 rods of 14 gauge steel wire to hold it together. I hoped that the redundancy of multiple rods would help straighten out the frame, which is why there is 4 rods per segment. The first time I designed the frame parts I actually made the holes a bit too small, so I made sure to update the design accordingly.
I didn't start by building the frame, since I knew it would be a bit difficult to bend the wire within the structure for larger and more complex tracks. Instead, I built the base, mounted the motor, built the lift, and then started constructing the track within that.
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| In-Progress Marble Machine with Frame |
Forgive my workbench I know it's a mess.
If you happen to be interested in these frame parts, you're in luck! I've uploaded the files for free on Thingiverse here! (Just make sure to follow the Creative Commons License or the ghost of copyright will haunt you).
Track Switches
If you remember my other machine, I had a seesaw mechanism to split the incoming marbles into two streams, one for each track. This was a good first attempt, but had several problems. One of the biggest concerns I had was the amount of height lost with the mechanism, and since I wanted a longer track, I needed one that was more 'vertically efficient'.
So I made a first attempt.
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| A very sad and crappy marble switch |
I don't know why I even thought this would work.
Then I actually did some research and binge-watched all the David Morrell YouTube videos I possibly could until I figured out the secret of marble switching. Then I went back to CAD, drafted up a design, and found it worked like a dream.
So then I made two more, for a total of four different tracks for the marbles. My plan were to have the tracks as follows:
Track 1 - Funnels with marble collector
Track 2 - Spirals
Track 3 - Loop!
Track 4 - Long windy track with standing marbles
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| Top of the lifting mechanism with 3 track switches |
Lifting Mechanism
I did an entire post about the lifting mechanism so if you're curious about the design process of that, read it here. I promise I'm not just lazy and don't want to write about it again.
Funnels
I wasn't sure how well a 3D printed marble funnel was going to work, but I decided to include one anyway. I experimented with two different types of funnel profiles, one that was a sort of logarithmic swept curve, and one that was just a funnel in a straight line from the edge to the hole in the middle. I came to the conclusion that the straight profile actually gave a better spin time so that's the one I went with for two of the three.
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| Overhead of the three funnels |
Spiral Track
I wanted one of the tracks to include a spiral or two, so after fiddling around with the patch workspace in CAD I created a template that I hoped would help me bend perfect spirals. After learning how to actually use the template effectively, I managed to create two spirals of varying sizes for the track that actually work pretty well.
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| Large spiral near the top of the sculpture |
Marble Collector
I figured it would be quite fun to have the funnel track collect four marbles before running them all down the funnel, instead of one at a time. To do this, I spent way too much time thinking about how exactly to balance the tipping arm, drafted something up in CAD, and ended up with a fairly good working design that collects 3-4 marbles before sending them all down the track together.
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| Marble Collector! |
YouTube Video
There's a whole lot more to this track than I can possibly explain, so I'll leave you with a YouTube video of the sculpture in action! That way you can watch it over and over again similar to how I turn on this sculpture and watch it for hours at a time.
So anyways, thanks for reading and watching that excellent video, I hope you had as much fun as I did! There might possibly be another sculpture in the works but I can neither confirm nor deny :)
Keep on making things!
- Will
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