This is a derivative of http://www.thingiverse.com/thing:4458. When I built the shorty version I had trouble getting the parts to print correctly and I wanted the ring to turn further to fully open the box.
When I designed this iris box I started from scratch and used a different mechanism to open the box.
I have also uploaded the NX6 .prt files for anybody who wishes to use them.
To assembly the iris box you will need to first print the ring, one peg array and 5 shutters. There are 6 pegs in the peg array just incase one is lost or broken, it's easier than printing another entire array.
I have uploaded a file called IrisBoxShutterArray.stl with all 5 shutters in it, but if you are having troubles with warping you may want to print them off one at a time using IrisBoxShutter.stl.
The last part to print is the base. I have uploaded 3 options for the base, there is the standard one that is 45mm deep inside, a small ring with no bottom and a tall option that is about 85mm deep inside.
To build this iris box you will need some 3mm filament or an extra set of pegs (either scaled down or cut down to 3mm diameter) with the wider part cut off.
Once all of the parts are cleaned up, you first need to test the shutter parts for clearances. To do this take the 3mm filament and run it along the track in the shutter. It should freely move the entire length. If it doesn't use a knife and widen the outside curve of the track until it does. If you skip this step some of the shutters may stick and not close all the way.
The next clearance check is to put a pegs through the hole in the shutter with the wider portion of the peg on the same side as the track. The peg should freely rotate, if it sticks take the peg out and whittle it down until it rotates freely.
Now push the pegs into the holes in the bottom of the ring. If you are lucky then they will go in easily and stay in firmly, but if they are wiggling you will need to pull them out, put a dab of hot glue on the end and quickly shove it back in.
To prepare the base, put the 3mm filament (or extra pegs) in each of the 5 holes around the perimeter and trim them to about 2.2-2.8 mm from the surface.
The final clearance check is to take one of the pegs and insert into each of the tracks in the base and slide it along the length to make sure there are no blockages.
To attach the upper assembly to the the base you can reference the pictures to the side. You first line up the pegs with the larger part of the slots and push them in being careful that the shutters are rotated out of the way of the pegs in the base.
Now rotate the ring slightly counterclockwise so the pegs in the base line up with the slot in the underside of the shutter and push the shutter in. If it is too hard to push, trim the peg in the base down, if it is too loose you will need to pull the peg out and start again, otherwise it could flip open during operation.
The last thing to do is have fun flicking it open and closed.