For the “Free Form Thick Layered Object Manufacturing” technology that is being developed at the Delft University, it is vital that Extruded Polystyrene Foam (XPS) can be cut accurately with a heated blade. The shape of the blade is actively controlled during the cutting process, which results in double curved cutting surfaces. In order to make this cutting process controllable it must be known how the cutting behavior is under varying conditions, like cutting speed, cutting angle and heating power. The authors executed a range of experiments, analyzed the results and describe a practical model for the cutting process of XPS with a heated blade.