Once you buy the "basic kit" you have to add:
- 3x 40w cartridge heater (the same used in RepRap 3d printers), or a band heating
- A temperature control module: a PID, an industrial thermostat or a PID based on Arduino.
- An hopper that could contain the polymer you want to extrude; our is 3d printed, but why not use lasercut to make it?
- A power supply with at least 15A on 12V output
- A temperature sensor (sometimes integrated in commercial PIDs)
Those are the components we use in our project, obviously if you are a maker you can modify the project based on your own needs!
Note that the project is open hardware and will be released on GitHub as soon as we came home from Rome Maker Faire