After seeing Big Hero 6 for the first time, it felt like Hiro's robot was ideal to make with the 3D-printer.

I think that Hiro also might have used his 3D printer to build him. Hiro used some kind of magnetic system for his robot. I want to make just a model and thought that bungee cord must be the way to go.

First I tried to print just the 9 parts, but I didn't like the result so I decided to print al the parts in two pieces.

The head and the bottom ball are the same, but for the middle ball I used a different design. All in all there are just three different parts to print.

Step 1: You Will Need

Materials:

Bungee cord (5 mm)
Acrylic paint (yellow and white)
3D filament

Tools:

3D-printer
Sandpaper
Super glue
Sharpy
some metal wire
Brushes
One M5 bolt
Scissors

Step 2: Print the Parts

I designed the parts in 123D-design, so I added both the STL files for printing and the 123dx files to tinker with.

It was kind of hard to come to the final design, because the dimensions aren't the same in every shot of the movie.

All the arms, legs and ears are the same, so you can print that file six times.

The head and bottom part of the body are also the same, so you can print "body2" two times.

Body3 is the middle part of the body. You have to print half of the ball two times.

All 9 parts of the robot have two pieces, so in total you will end up with 18 separate pieces.

I used a Robo3D with PLA. No raft, no support.

Step 3: Prep the Balls

To make sure that both halves of the body-balls fit nicely, I sanded them on a flat service.

Next I glued the halves for the head and the bottom ball together with super-glue. (Don't glue the middle ball yet)

On the one that is going to be the head I drew a circle where the face will go. I used a metal ring for this, but something like a toilet roll would also work.

Step 4: Prep the Arms

I also sanded the two parts of the arms that will go together.

I pushed in a M5 bolt to align the two parts and glued them together with super-glue. If you use to much super-glue it might be hard to get the bolt back out.

Do this for all nine arms (legs and ears).

Step 5: Add the Bungee

Put a knot in one side of the bungee cord. You will need a piece that is long enough to go trough the three balls.
Cut the bungee just above the knot.
Push the bungee through the middle of the 'head' ball, entering on the side with the wider hole.
Pull the bungee through until the knot is al the way inside the ball.

Put a knot in an other piece of bungee. This must be long enough to go through two arms and one ball.
Push this bungee through an arm, entering from the smaller side of the arm.
-pushing it through was very hard, so I made a hook out of a piece of metal wire to pull it through-
Now pull it through the slits on the side of the ball that already had a bungee going through the middle. The new bungee goes over the knot in the old bungee, so they should not meet each other in the ball.
Pull this bungee also through the other arm.
Pull the bungee out a little further (it is elastic) and put a knot in it.
Cut off the excess bungee at both knots.

Step 6: Add the Next Pair

For the middle pair, you first bind the two arms together the same way, only this time without the ball;

Put a knot in one end of a piece of bungee.
Pull the bungee through both arms, with the thick parts in the middle.
Put a knot in the other end of the bungee.
Cut off the access bungee from both sides.

Put the bungee that is coming out of the head and push it through one half of the middle ball.
Pull the two arms apart and push the bungee that is in between the two arms, in the slit in the half ball.
Put the other half of the ball on the bungee.
Glue the two halves together.

For the bottom pair, you put the ball on the bungee and than put the legs on;

Pull the bungee that comes out of the other two balls, through the middle of the last ball, with the wide hole on the bottom.
Pull the bungee hard through and put a knot in it.
Cut off the extra bungee.
Pull the knot all the way into the ball.