Hi Kong,
Try a 2 flute cutter if you aren't already. The problem is that the chips can't get out of the way of the cutter as it comes around on it's next pass. Therefore it packs up on the bit. You should be able to pick at it and get it out of the bit.
Also if you can, it would help to slow your router speed down some. Again that is because the chips can't eject fast enough.
They make grease sticks for cutting Al but short of that simple spray vegetable oil works too.
Good Luck,
Chris |