A hot wire CNC foam cutter is a computer-controlled machine that uses a heated cutting wire to cut EPS and XPS expanded polystyrene foams into three-dimensional shapes. The cutting is done with a nozzle that is mounted on the end of the hot wire.
It is a great tool for building model aeroplanes as it can cut any airfoil shape from a 2D CAD design. It is also useful for cutting out complex contours such as tapered wings. The machine is simple and cheap to build with off-the-shelf components. It is easy to assemble and can be started up in under two hours. It is also easy to learn and use and can be used to make any type of 3D object.
There are a lot of different softwares that can be used to generate the G-code and control the machine. Most people use hot wire CNC foam cutter or Profilli but these programs are not free and require a PC with a parallel port.
The core of the machine consists of an Arduino Mega 2560 and Ramps 1.4 with stepper drivers and motors. The hardware is based on the open source design by Garret Visser and Daniel Rascio. This design allows for independent jogging control of all axis including homing. It also has a graphical display of the G-code and a setting panel for the nozzle temperature.
Besides the Arduino Mega and Ramps 1.4 you will need a few other components. A power supply that can deliver 3.3V is necessary as the stepper drives will need that voltage to operate. Also a fan that can blow on the wire is required to keep it cool. A heat sink is also recommended to dissipate the heat generated by the nozzle.
It is best to experiment with the settings for the nozzle temperature and feeding rate before starting to work on actual projects. You will need to find a balance that will produce clean cuts with minimal melting of the foam. It is important to keep the nozzle temperature low enough to avoid melting the foam but high enough to be able to get accurate cutting.
Depending on your application it is also worth looking at using an alternative to nichrome for the resistance wire. Steel fishing lines are suitable and they tend to last longer than nichrome. Generally you should try to use the thinnest wire possible to decrease the kerf formation while cutting and to give clean cut edges.
The P 60 series of machines come standard with a 0.1kg spool of NiCr cutting wire which should last for approx 5-10 hours depending on the settings you choose. It is also possible to upgrade to a Titanium Alloy Wire that lasts five times longer and has greater stretch resistance at high temperatures. This option is available for all our 1.3 meter wide and wider machines. This is an additional charge but the cost is still much cheaper than purchasing a new spool of NiCr each time it runs out.
