A robotic styrofoam cutter with one rotational and two translational axes that cuts a variety of shapes out of styrofoam-like materials using a hot wire. The source code and schematics are available at sourceforge.
For the horizontal axis we used an old dot matrix printer. The other two axes are made of fischertechnik - a construction set that features aluminium profile elements.
Our planning software runs on a PC and either imports STL files or lets the user create rotationally symmetric forms by drawing their outline. In both cases we generate a program in our CNC language. This gets compiled and commands are sent to the microcontroller which controls the stepper motors.
The hot wire has to be cooled by two fans to prevent overheating outside the styrofoam.