Welcome to the Machine

Experimenting with the ShopBot, By Jason Gray

Recently I took a three-week summer class covering digital fabrication. We had the opportunity to work with a ShopBot CNC router, a laser cutter and a few 3D printers. I focused on the CNC, as it is the most useful in the scale I work in, and the machine I am most likely to use in the future.
While there are many examples of CNC-built furniture and sculpture pieces, most of them use off-the-shelf plywood and were obviously designed on a computer, using generic mortise and tenon shapes.
My goal for the class was to find a way to use the CNC technology in a way that did not scream "I made this on a cnc and put it together!" but also take advantage of the machine's capabilities, creating something that would be extremely tedious and nearly impossible to cut by hand.

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I found my inspiration in living hinges. A living hinge is a hinge made with the same material as the two solid pieces being hinged, such as a styrofoam take-out container. The whole thing is made of the same material, and the hinge is made by a skinnier section of the styrofoam. The book cover on the right is an example of how living hinges are made in wood; this one was laser cut. It is the same principal as kerf-cutting plywood to make it bendable, but this method makes perforations through the ply rather than shallow cuts. I was curious as to whether or not this idea would work on thicker material. 

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The examples on the left are my test pieces. The plain plywood ones are 3/8 birch, and work fine. They bend to a degree, but are pretty basic in appearance. I wanted something more interesting, using a pattern that was more organic but still had the same capabilities. Which is where the black one came in. It is much more interesting, and even more flexible.

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This was my most successful test. Again it is plain 3/8 birch plywood. As you can see on the right it can roll back onto itself. What happens with this forms is the skinny parts of the patter are actually being twisted, ever so slightly. One or two sections won't do much, but when the slight twist is added up over several sections, it becomes a significant curve.

Once I knew I could make the thicker ply bend, I had to decide what to do with it. My first goal was to get rid of the store-bought plywood. Aesthetically it is unappealing to me. I ended up making my own plywood, what is called solid core or lumber core ply. 

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I cut 8/4 poplar into 1/2 inch strips and laminated them side by side to form a panel. Then I covered both sides with two layers of walnut veneer, with the first layer laid cross-grain from the poplar. In future versions I will use nicer wood for the center; I just used what I had on hand in case my idea failed. By making my own plywood, I eliminate the usual look of plywood and gain the ability to have contrast where the cuts occur. I could push this in many ways, with alternating the woods used for the layers. I could also do it out of all the same species. From a structural standpoint you no longer have the possibility of hidden voids within the mass-produced ply, which could make the bend fail or appear inconsistent. 

After I had the idea of making my own ply I had to decide what to do with it. I could attach it along a curve, making a chair or any number of things. I didn't want the beauty of the shape to be hindered by the support structure, so I decided to make it a simple cylinder and turn it into a pendant lamp. Down the road I may try other forms and uses, but I am really happy with this final object as it is.

There's still a little sanding to finish in this picture, but it gives you a better look at the details.

  It was a fun process to learn, and I intend to experiment further and see where I can take it.

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