Sounds like your RPM is too high and feed is a little slow. You also didn't say how many flutes on your 2mm endmill?
I haven't had good results with a 2mm tool, they tend to flex a bit and that ends up with heat and melt problems as a result. They also blunt too quickly (again more melt).
I would suggest 3mm or 1/8" endmill, 0.5mm depth, maybe 8000 RPM and similar feedrate. Some people use a hand spray mister with the occasional mist of water or water with a couple drops detergent, or maybe a steady blast of compressed air to clear the chips and cool the tool.
And a NEW sharp tool that has not been blunted by the blunt students yet...