Tensegrity Vase Table

Summary Section: 

Did you ever want a small, mobile, and stylish floating table? Look no further than the Tensegrity Vase, a small, but strong structure that looks like a vase, but is a table! The Tensegrity Vase can hold up to 4 pounds in a portable 16cm x 16cm x 16 cm frame, and weighs less than a pound! Usable for everything, from decorating an empty space to a convenient cup holder for when you are out with friends. For this project, I worked with Edwin Estrada-Diaz, and his page is linked below. WARNING: make sure to use strong and structurally sound filament when printing to produce desirable results. Weker filaments will not guarantee structural integrity for the vase.

Edwin Estrada-Diaz

Fishing line

Hooks

Lesson Plan and Activity:

With a partner, you will design and create a single custom Tensegrity Structure of equal complexity or greater than the tables depicted above (as determined and approved by the instructor).

Constraints:

• The design MUST take advantage of print orientation to create the strongest structure possible.
• Each piece should fit inside a 15cm x 15cm square.
• When constructed, the final structure should fit in a 20cm x 20cm x 20ish cm cube.
• Parts MUST begin with a constraint box,                 center-rectangle CENTERED ON the origin)
• No single dimension can be smaller than 0.25cm
• All “plates” MUST have a thickness between 0.75cm and 1.00cm
• All “beams” should have a thickness of 1.00cm
• Engravings should be cut to a depth of 0.07cm
• Dimensions should be detailed but efficient.
• Sketches should be fully defined when complete.
• Parts MUST contain zero error messages.
• Structures MUST be assembled virtually before 3D Printing to ensure successful models.
• Screw hooks and fishing lines will be provided for attaching your pieces.
   

Parts List: 

2x 11-cm Bars

1x Bottom vase part

1x Top vase part

At least 10x hooks (recommended 15-20x)

At least 150cm of fishing line (recommended 170cm+)

Assembly/Construction Instructions Section: 

1. Assemble your necessary tools. You will need a Philips head screwdriver, a hammer, pliers, nippers, hooks, and some fishing line to use as string. A hot glue gun is not required but is highly recommended. 

2. Find the circular extrusions in the vase parts and insert the hooks by holding them with pliers and screwing them in. If the holes are not large enough for the screws to fit in, hammer down a screwdriver to open up the hole and twist. If that also doesn’t work, hammer the screw directly into the hole.

3. If the extrusions break, use nippers to chop off the ends of the extrusion and if the hooks are still wiggling, use hot glue to secure the screw.

4. Put the bars into the square extrusion by pushing the bar down into the base (if the bars wiggle too much for your liking, add hot glue underneath the bars BEFORE inserting to secure). This might be a very tight fit, so feel free to use force to push it in.

5. Tie about 35cm+ of fishing line around corresponding hooks (hooks that are directly above each other) in a loop, and tie a square knot to secure the string (here's the link to a square knot tying video). To tie a square knot, grab both ends of the string, criss-cross them, bend one end back and make a loop to pass the other string through. To tighten, pull each end in opposite directions. Make sure to leave some extra room in case you need to tighten or loosen the string later.

6. Tighten strings by gripping both ends of the line with the pliers, and pulling the pliers away from each other slowly. Start with the short loop in the middle (it can be tightened as much as you want), then move on to the corners. Generally, try to go for small improvements in each corner and continue to gradually get tighter throughout the entire structure. It is not advised to suddenly tighten one corner very much, hence why you should go slow.

7. Use a level to balance out the final product and assist with the final tightening of strings. All the bubbles should be in the central rectangle of each segment of the level. The top of the vase should be parallel to the bottom of the vase. Use nippers to trim any excess string. Slide any knots downward toward the base of the structure to hide from view.

8. Admire your final product and test how much weight it can hold!

Design Choices: 

Our initial idea for the table was to assume a very harsh, rectangular, pointy table with lots of sharp angles. However, we soon realized that sharp and pointy edges wouldn’t be the easiest to carry around, and shifted toward a rounder model. Our earlier sketches looked like this, with a round top and bottom, and not-quite diagonal bars.

We wanted to use the twist tool after playing around with it earlier in the year, so we went onto printables to look for more inspiration. After seeing the abundance of vases on Printables, we were inspired by this vase and wanted to make a slightly more complicated version of it and transform it into a table. Our next sketches were all centered around the idea of creating a vase, slicing it in two, and then shelling both parts to create a hollow interior to place the bars. Our final sketch with dimensions was then created, but as we worked on the structure it would change drastically to add new features and conserve more filament.

We started off by directly transferring the sketch into Solidworks, and they turned out like this:

We soon realized that we didn’t leave room to insert the bar. Since we didn’t want to create a hole that went through the bottom of the base, we decided to make an extrusion to hold the bar in both the top and bottom. Since there were issues with Solidworks not recognizing the inner face of the bases, and there was no central axis for the vase, we decided not to precisely measure out the placement of the extrusion. Instead, we set them relative to a few points around the edge of the inside of the vase. They looked like this in Solidworks, and the assembly looked very good.

Once we printed out the vase, the problems with our design became very apparent. First off, as shown below, our parts were way too big and used too much filament.

After going through a difficult assembling process where we had to essentially ‘guess’ where the holes were supposed to be and had to string the pieces together in hard to reach places, Our final product was created. However, it was immediately apparent that the pieces weren’t aligned properly. The end result was slanted to one side permanently, and the bars were so close together that they practically leaned on each other, removing from the magic floating effect we wanted to achieve.

In our second revision, we made a whole checklist for what we needed to change.

Each change would affect a different part of the functionality of the vase and would hopefully make the assembly of the vase easier and less unpredictable. None of the changes were aesthetic, other than the choice to reduce the size down because of concerns of printing time and size. 

We started off by fixing the face not being recognized as a plane, which directly affected our ability to print clean extrusions on both our bases. After fixing that issue by extruding defined planes to certain heights, we decreased the thickness of the bases to make the vase more lightweight, consume less filament, and make the vase less top heavy, as evidenced by the precarious leaning in version 1. We also tightened the hole created to hold the bar to reduce wiggling and improve the general stability of the vase, adjusted the length of the bar and overhang to create more area to place the hooks for an easy assembly, and added more extrusions to place the hooks so that we knew where each hook had to go instead of blindly hammering them directly into the base. Our final parts looked like this (with cross-sectional views):

Our choice to create extrusions to fit the hooks in also helped us conserve more filament, which was one of the most pressing issues in the project.

Finally, it was time to print version 2, and we chose a multicolored rainbow filament. The parts came out looking like this, already much better than before and much more lightweight and portable.

However, once we started assembling again, we realized that the filament, while pretty, was not at all structurally sound. This caused hooks to pop out of their sockets, the extrusions we made to hold the hooks to snap off, and the bars started to crack in the middle. We had to resort to gluing the bar back together, hoping for it to work and for the screws to not pop out.

However, even after applying two layers of glue and letting it dry for a whole day, placing more than 1 iPhone's weight (less than 8oz) on top of the table caused the structure to break due to screws popping out of the weak, cracked bars. We decided that we had to scrap version 2, and our end result looked like this:

However, since all the improvements we made to the model technically worked, we decided to choose a different, stronger filament and reprint it and see how that worked. Choosing a stronger filament may have been the most important decision we made throughout the entire process, and if you choose to make a vase like this as well, MAKE SURE YOUR FILAMENT IS STRONG. Thankfully, after going through a quick and easy assembly, we finished our final Tensegrity Vase table and ended up with the masterpiece you see above.