Hello,
how does the problem look like?
To get good results in EPP you'll need sharp tools (never use them on anything else before), as high as possible rpm and the flutes of the tool should be straight.
A large tool diameter also helps - if the tool is too small it will start ripping out EPP beads very soon and may break once it heats up and gets wrapped by molten EPP.
However the surface will always look a bit felted unless the tool is razor sharp.
Christian