While finding out a nice way for cutting plastic with a hot wire I faced the problem that if the temperature and cooling is too low, the wire can cross the plastic without actually cutting it.

That happens, because with a low temperature setting the wire just melts the plastic without evaporating it, and without cooling, it just fuses back together after the wire moved far enough away from the molten plastic.

The whole time, I was a bit unsatisfied with the machine, because while it can cut out simple shapes quite nicely, there was no way for starting a cut "inside" the later workpiece without cutting unwanted paths into it which weakened the part or made most cuts completely impossible.

At least that's what I thought until now because I just realized that I actually can cross the part without cutting it and that I already did it before. 

Doing that intentionally will leave a "scar" on the workpiece, so it may be not suitable for decorative parts, but for only functional parts, it will add a lot more functionality to the machine.

To make this a reality the machine needs to be able to control heating power, fan cooling, and feedrate.

I think using this technique could actually work and I will now start working on the implementation.