A few weeks or so ago, @sailindaze suggested for the tentacle mechanism, Sugru could be used as the ‘hinge’ part, since it will be springy. @sugru caught our discussion and offered us some free Sugru! I received mine the week when I was at C2MTL, so as soon as I came back it was pretty awesome to get started with it.
They have a great tutorial video about moulds and sugru here. Definitely check it out if you want to try a similar experiment.
The first step was to create the model of the mould! We created this in Autodesk Inventor:
Instead of going full out with printing the entire vertebrae for the tentacle, we decided to go with ‘hubs’ first.
The moulds printed nicely- except for the extruded guiding parts (they snapped off). It wasn’t too big of an issue:
One of the tricks to moulding sugru is adding some dish soap to the mould prior to adding the sugru.
This is what the sugru looks like, after opening the package!
Added the sugru to the hubs:
Packed it into the mould:
After compressing a few times and taking away the excess material- tada!
What the moulds look like after:
The final result:
After waiting 24h for it to set, it was time to test it out. First I tried bending it, and it broke:
All the way across:
It kind of pulled apart when picking at it, and it was still not set in the middle:
So that experiment #1 didn’t work out too well. I wasn’t entirely sure if it was because of the hubs having sharp corners, or maybe because of the strain relief indents being too much… or maybe there was just too much sugru and it couldn’t move very well.
Time to redesign for experiment #2!
This time, it was much smaller and the pieces less sharp.
Adding the sugru to the hubs:
Adding the sugru to the mould:
There was some extra sugru, so I tried this as well:
The resulting moulds:
After waiting 24h for it to set… it was really hard to bend it, but same issue:
The 3D printed hubs are breaking…
Inside the moulded piece:
It’s too bad that the experiments didn’t work. We thought the sugru was going to be a lot springier, rather than tearing when it was bent. The sugru itself is pretty durable- for repairing things we would highly recommend it Thanks to Sugru for the free sugru, otherwise we wouldn’t have been able to try this experiment!
If anyone has any suggestions for what material to try for this sort of thing, or any ideas on how to do a better try at an experiment, please let me know!
Also, if it is of any help to anyone, the sugru experiment files (.stl and raw Inventor) can be found on Thingiverse here (thing:97104).