Building a CNC Hot Wire Foam Cutter
Some of the early prototypes of the boats lacked boat-like form and as the prototypes got more complex it was clear we needed a tool worthy of the job. I settled on a 2-axis hot wire CNC, controlled by G-Code, to help make better boat hulls and wings. This was because expanded polystyrene foam has OK mechanical properties (very light buoyant and waterproof), is economical and convenient - since I can buy it in huge sheets from B&Q just up the road. The CNC hot-wire consists of a bed with 2 parallel rails that support a vertical tower. The tower has a pair of carriages that run on either side of the foam sheet. The carriages have a length of nichrome resistance wire between them that gets hot enough to vapourise the foam and thereby make a smooth precise cut. The machine can move the tower left and right (x-axis) and the carriages up and down (y-axis). The CNC hot-wire is controlled by an Arduino running GRBL. The step and direction signals from GRBL go to two stepper drivers ...