Press-fit Construction Kit: 3-D Tetris

This week's assignment was to use a laser cutter to create a press-fit construction kit. This project reminded me of one of my (and your?) favorite childhood games, Tetris: I would have to figure out how to fit different types of pieces together. Inspired by my many hours of fighting boredom on long road trips with my family (and, later, procrastination in the pre-Facebook era), I decided to make a 3-D version of Tetris. 80s/90s nostalgia FTW!

This time, instead of pressing the A and B buttons on my big fat gray Gameboy to put the pieces in their place, I designed little joints that would connect the faces of each Tetris piece and each piece to each other. I designed 4-mm slots for a tight fit. I created my image file in Inkscape:

The black elements are the faces of each Tetris piece, and the blue elements are the joints. At first I tried to use CorelDraw. When I opened my .png file, I was unable to convert the shapes from filled into hairline outlines. Then I tried opening the .svg file, but the file looked completely different: the lines went all over the place and were very jagged. Since I did not want to re-create my file in CorelDraw, I switched to the Fab Module.

Using the Fab Module, I converted the .png file into a path file for the Epilog laser cutter. Before actually cutting the cardboard, I lifted the glass to allow the laser to simply trace the path. I noticed that the laser went way off the cardboard and onto the metal guides--obviously, something was wrong. I was confused because I had set my Inkscape page to the proper settings (24 in by 36 in). I asked a friend with laser cutter experience what might be happening, and she explained that it was possible that Inkscape and the laser cutter program were measuring inches or pixels on different scales. She was right. Inkscape had set more pixels per square inch than the Fab Module, so I resized the image correctly. This time, the little red pointer never left the cardboard.

I set the laser cutter to 40% power and 60% speed. Even though there was occasionally some smoke (I have to admit, I got a bit nervous a fire might start), the laser did not completely cut through the cardboard far from the origin, so I had to punch out the pieces in the bottom right corner. Also, the laser cutter unexpectedly flipped my image on both axes.

On the laser cutter:

After removing the pieces:

My resulting pieces:

I made many, many joints:

The joints fit into the faces as follows:

...but before using those joints to construct 3-D Tetris pieces, I had some 2-D fun:

3-D Tetris pieces, as individuals:

And put together:

Or you could ignore my Tetris intentions and fit the pieces together however you want. Because the faces also have slots, you can put them together without joints. Here I constructed something random using the tetris faces only:

That's it! By the way, I was very, very tempted to add the Tetris music to this website, but I resisted. You're welcome.

As a reward for reading all the way to the bottom of my webpage, I give you the gift of procrastination! The flash version of Tetris below is played with your arrow keys. The up arrow flips the pieces. Thanks for reading!