I’ve been chasing a single line tensegrity sculpture design. Up to this point have all been half failures. I think I finally have a successful design.
This is a test printed in PLA. Single line tensegrity sculptures require compression to pull on the single line to create tension so it can stand on its own. PLA over time will deform with the compression so this just a test. A better option is PETG which I will print at some future time after this fails.
The spanners need to be a tiny bit shorter to create a bit more compression and more tension so it doesn’t sag as much but I think I have a winner design with a few tweaks.
You need a shape that you can compress that wants to spring back. You need to constrain the spring back (super glue) along the fishing line or thin rope and that creates the tension that holds the pieces upright.
I don’t know why it took my brain so long to understand the concept but fairly easy.
And this is what happens when a cute little kitty cat named CiCi decides to fling the sculpture off the table in the middle of night and scares me wide awake. I am shocked it did not blow up but something deformed/gave. lol
I initially saw the concept in a very different model by ErnieC53
So I stopped looking for any more examples so I could design something unique without being influenced by an existing sculpture. After completing my design, I then looked to what had been done in the past.
lol. My design had only been out there probably hundreds of years. Nothing unique.
So if anyone wants to play with this here is the 3d print file.
It can be done with PLA but better with PETG due to the compression and tension required. PLA will droop after a while.
The more tension, the stiffer the sculpture will be but also the more tension on the piece with the chance of the glue bond to fail so a bit of a balancing act. You can resize the spanners slightly smaller to increase compression to play with tension.
Thread the parts and then stretch the line as much as possible and then use the spanners to compress the elements. Use superglue on each point where the line contacts the elements. Allow it the glue to fully cure. There will be an amount on tension that will be pulling on the glue joint.
I used fishing line but any thin line that can stretch will work. The tensegrity structure fits the base with a friction fit and is tight. You may have to force it in an out a few time so it slips on easier. Do this first before the glue up.
Cool. You can try this Desktop Neon Effect LED Signs too. These ones can be powered by either a USB cable or 4 x ‘AA’ batteries giving you a lot of flexibility for placement. They are also dimmable to help create the right level of ambience for any setting.
Well first iteration was a complete failure. I made it too delicate. When I squeezed hard on one of the circles it cracked. Additionally, I printed them as two halves so I could glue them interlocked with each other for simplicity. Under pressure they make an ugly pinched area.
So remodeled the circle links so they are printed solid as well as a bit more robust. It doubles the print time but hopefully it can survive the tension better. I’ll try 40% infill instead of 30% due to the new orientation. Balancing act between weight and tension.
Also, I will find out how well PETG supports come off itself.
You made it “easy” on yourself by doing the initial tests with the “C” shapes AND keeping them all in the same plane. I say “easy” because you could pre-tension flat on the table just as they would eventually float in the air.
But this new “O” design you alternated the plane of each segment so layup and gluing gets trickier. Maybe your tension system becomes a single unit so it can be tension-ed in the vertical plane and in its mount?
I’m thinking of a small simple middle school project to teach tension and compression using something like what you did the the “C” shapes.
That would make an awesome and fun school project. PLA does work and depending on infill may last a long time.
My plan is to elevate the design horizontally so I can keep the parts perpendicular as I glue them in place without fighting gravity. The spanners will be going to one side of the string just far enough away that I can apply the super glue.
That’s the plan at least. We’ll see how far it survives after contact.
PETG definitely a bit tougher to print in my office. It is a very drafty room with multiple fans. On my third iteration, one of the links failed so ended up with only three links. Enough to test my glue process though.
First iteration print failed, second iteration printed fine but the segments were too thick and wouldn’t bend easily, third iteration reduced thickness but one link failed.
First iteration printed fine but I disliked the design so redesigned.
Second iteration printed fine but my redesign was too thick and wouldn’t compress easily. Redesigned to be thinner.
Third iteration print failed. Pushing the limit of my build plate with tall skinny print elements. Adjusted the links.
Third attempt to print failed. One circle broke off the build plate and took another with it. Readjusted the links.
4th attempt to print failed. Not exactly sure why. Top portion of one circle came off.
5th attempt to print failed due to power loss to the house. Was one of those that power would come on and off for a few times before finally going off. Got a text from the electric company a tree had come down on a power line. Waited a few hours after power back on and re-attempted.
6th attempt to print failed again due to power loss to the house. This time was able to restart the print but file was somehow corrupted. Part of the file did not print.
7th attempt just started. If this fails I am going to quit. Almost two rolls of PETG filament and almost 3 days of wasted time.
I/We understand how it feels. I have been working on a project for over a month, and have cut five different iterations of parts. I have assembled and adjusted and reassembled parts. And still working on the same idea. And when I am done with this project I will have only proven to myself that it can be done… Not the grand new thing, the CNC to beat all cnc’s, but to make ‘my’ router table solid as a rock.
At least you project is cool looking, so there’s that…
Thank you for the words of consolation/encouragement. lol
Woke up to a successful print. Cleaning up the supports was fun. I added a bunch and had them going every which way to add additional support as compared to my earlier attempts.
Now I want to design a new stand for it after all that effort.
My initial thought was a hand coming out of the ground to hold the first ring.
After cleaning up the supports I needed to sand some of the circles but had the thought, “they look kind of thick”. Took a tape measure and realized when I redesigned the links I messed up the numbers in my head and redesigned the new sculpture to the same size as the old sculpture. Even I amaze myself on how to mess up stuff. A possible solution is to reprint the spanners to compress the circles by 1/4" versus the 1/2" I was originally planning on using.
