Foam is a common material for rapid prototyping, it is cheap, easy acquire, and fairly easy to work with if you have the right tools. A tool that makes working with foam even easier is a hot foam wire cutter. You can manually use one to prototype, but that leads to sloppy cuts and wasted time. This CNC adaptation to a hot foam wire cutter allows for quicker, and cleaner cuts in 3 dimensions of foam to allow for a more polished foam prototype. 

Consisting of the hardware, software, and an Arduino to interface between the two. The technology itself is not overcomplicated. The CNC machine uses a total of 3 stepper motors, two to move linearly on the X and Y axes, and one to rotate the foam on the Z axis. The next piece of hardware was the hot wire itself, which was simply a piece of Nichrome wire with a small current running through it. On the software side of things, we manually wrote the G code for simplicity, but the software used to compile the G code came through "Universal G-code Sender" (UGS), which is a platform that can accept most G code files. The Arduino used to interface, was a standard Arduino Uno that was aided by a CNC shield that attached directly to the Arduino. Through the combination of these various technologies, we developed a more robust technology that was used to help represent various CNC principles in the classroom. 

The above image shows some of the improvements that were made as our machine and our G code was updated. For example, you can see the foam block on the far left was cut in one dimension all the way through, and after an attempt at a second pass it was adjusted because it did not rotate the Z axis enough to reach our desired 90 degree cuts. The next block from the left is slightly better, but unfortunately our Nichrome wire broke after 3 passes of the wire, leaving one side of the profile undone. Our third attempt (third from the left) is improved, it was mostly cut to specification, unfortunately our adjustments to the G code were not correctly set up for the 4th pass, leaving an undesired outcome. Finally, the last iteration to the G code (far right block of foam) cut cleanly as desired and left us with a nice geometric shape that 4 symmetrical sides at 90 degree intervals.