Computer-Controlled Cutting

Week 2

Vinyl cutting

Nathalie du Pasquier, 1984

To test the vinyl cutter, I wanted to re-create the marbled pattern used to create the cover of composition books--also used by members of the Italian Memphis Group. The design of the composition book's cover has passed from a slow, craft-oriented, laborious process to mechanization and industrial mass-production (you can read about its history here), and I wanted to see what our age's automation can contribute to its production history. I used Mathematica, following tips here, to recreate the famous pattern and vary it.

Composition book

Pattern 1

Pattern 2

Pattern 3

Pattern 4

I then traced some of these patterns in Illustrator & added a blob clipping mask to delimit the shape. I wanted to test the pixel limit of what can be cut and removed from the vinyl sheet, so I kept a test piece with linework only. The line weight I ended up using for the top figure was 2 pt.

Tracing pattern & playing with figure-ground

I wanted to see how easy the transfer process would be for small shapes and linework, so I created a set of blobs to test the cutter.

Testing different sizes and densities of cutouts (labor, loss due to transfer, line weight): the transfer process (with the sheet masking tape) was surprisingly successful.

Sticker transferred to my computer

Laser cutting

Layout for the stacked puzzle box

For my press-fit kit, I wanted to create several 3D or 2.5D puzzles that would stack up to create a small pen holder. I designed the stacks to have a loose fit, but I wanted them to hold against the pens or pencils that would be inside. I also loved the idea of play--of multiple possible configurations withing the same stacked puzzle system--that could engage me while sitting at my desk, waiting for a next project idea, puzzled.

Grasshopper definition for joint & curve generation

Second set of parameters

I first created a Grasshopper definition for the box so that I could vary the notches and generate the layers. The material I planned on using was 1/8" thick plexi.

Assembly

I spent some time finding the right material offset for the laser beam for a good fit at the corners, and I eventually found a 0.004" offset sufficient for a tight fit and easy disassembly.

Two faces

Assembly testing

Full box layout: some parts are interchangeable / can be assembled with multiple faces

Box assembled

I also wanted to test bending acrylic, and to do so, I made a simple cylinder that I was hoping to unroll and fold back into a perfect circular object. That was wishful thinking, though, because with the joints I created I could not force the object to close--nor did they hold well, because I accidentally doubled the offset. Even after sanding for a while, the extra 0.004" would not yield before the material did, and the end of one joint piece snapped off. I re-attached it with plexi glue, but sanding after that was almost impossible.

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Grasshopper definition for bent acrylic cut file

Failed cylinder

Breaking at the joint

Second attempt

My second attempt used two straight extrusions as well as curved sides. This immediately worked (with the same 0.004" offset) and I could assemble it fairly quickly!