Does anyone have suggestions for making a CNC mill that's quiet enough to run in my apartment? I'm thinking about getting one of the cheap $250 Aliexpress specials (I only want to mill PCBs), but I'm guessing it's going to be too loud to run in a building where other people live. If I can make some performance tradeoff for relative quietness, I'd love to do it.

(Maybe it's as simple as putting it in a foam enclosure or something? That sounds bad for spindle cooling, though.)