Week8 : computer-controlled machining

observing my child and her cusins play in the backyard with all the different materials they could find to construct different life size objects (A house, a car or even horse wagon with imaginary horses !) often it's flat on the ground. This gave me the idea of building large scale press fits that can be shaped to different 3D objects, finding the best unit/s that can work like simple 2D lego bricks was a bit challenging. I decided to start with one large object and work my way back to single elements that made this shape.

I found inspiration in those two projects, Lucia Koldova Igloo bookcase and Christina Sicoli Asterisk puzzle stool.

We started just a couple of weeks before our Shapeoko CNC machine, we followed the online manual and videos which were not always very easy. But after few weeks and all the team sharing the building task we managed to get it ready before the assignment week. But I ended up having a larger design than the build area.

I tried to use antimony in previous weeks, but I was not successful. This time I decided to spend more time, look at some examples and give my self some more time to get use to it. It turned out to be not so difficult, but my first attempt in creating the desired object was not exactly what I had in mind.

I used inkscape to make the file to be cut by a large CNC in a shope for one of our fablab partners. GRAPE VINE and the amazing 'SAYED ALI'

My design was ment to be large enough to accomodate 2-3 kids, and they should be able to build it themselves.

While working on the design it gradually start to look like a pomegranate.

After completeing the details I decided to use the autonesting feature in software used in ArchiCAD software, prior to sending to the CNC machine. But It turned out that the design would need 4 sheets of (4x8 feet). I decided to call off the cutting for the day and went home desapointed trying to figure out how I could reduce the size. But the purpose was to have this igloo for 2-3 kids to sit in it comforably ( or atleast have some space to move in and out) hence the diamete was 1.2 meters at the base.

Pomegranate SVG

Pomegranate DXF

That night I decided to give up on the Pomegrante-Igloo for now and try to think of a design that could fit in one sheet or less. I had an idea of doing something I always wanted to own. I was very close of purchasing it online once, but I remmber thinking this is simple to do on a CNC.

I tried it once at a friends house and it was really very comfortable and for someone like me who finds himself sliding gradually in my seat after few minutes i thought I should try and do one for myself.

I wanted the sides of the chair to look intersting and after stairing for a while at the design profile a familiar image appeared in my head.

And that's how the chair profile started shaping.

I did my measurements based on a diagram ment for an adult chair. And thought I would cut it in 18mm MDF boards so I decided to have the slits measure 17.8mm to have a fit joint.

For the seating and the knee support I thought of using fabric rope ( 3/8 inch).I had to keep the structure supported from the sides, because as I was tightining the rope the lower part started going further apart which gradually forced the joints out. I thought for the next iteration I would add a dowel to secure the joints against tension.

And obviously something that I forgot all about until I strated assembling, are the DOG-BONES!!!

I started to notice the lamination over the boards to crack around the corners when I realised that I forgot all about dog bones.

Design file SVG

Design file DXF

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