I wanted to make my press fit construction kit using EVA (Ethylene vinyl acetate) foam sheets. I have used it before in many of my craft workshops with children. I like it because they are flexible, easy to cut, are available in vibrant colors and can be easily found in any craft store. I wasn’t too sure if I could cut it using a laser cutter. I was afraid that it might catch fire. I started using a vinyl cutter to cut the foam sheet. I changed the knife settings and tried various combinations of force and speed. None of them worked and the edges of the shape were not smooth. Because of the flexibility of the material, vinyl cutter wasn’t the right choice. I checked the Epilog Laser website to find out if it is okay to cut EVA foam sheets and decided to use the laser cutter.

I wanted to get the joint right before working on the actual design. I drew a basic puzzle block using Adobe illustrator. I first cut a cardboard puzzle block using the following setting for Epilog laser.

Speed: 65, Power: 45, Freq: 700

For EVA sheets I changed the settings to

Speed : 85, Power:12, Freq: 700

Figuring out parts for the construction kit was the trickiest thing for me. I started with some hand drawn sketches of different kinds of insects and then chose to draw the image of a lady bug using illustrator. Here is the first version of the lady bug.

I made a cardboard model to test the design. After making the first model, I realized that it was a bit wobbly. Since EVA sheets are flexible, the same design for cardboard wouldn’t have worked.