Just completed my mill enclosure after a couple of years running it open. I'm hoping to limit the migration of aluminium chips around my house! The main reason for the enclosure is the air blast system. I always planned to use an air line to clear the chips and got an aquarium air pump from Ebay to supply the air - this was after I read on this forum about another person using these pumps. I can't find the thread any more but thanks to whoever it was. My pump is a Hailea 70 L/min, and I got some Loc-line to direct the jet onto the cutter. Obviously this blows chips about a bit so I needed the enclosure.
I can't recommend an air blast enough. I have been using GT-85 spray to lube my cuts (like WD-40) and this gets pretty tedious standing by the machine all the time. With the air on, I can leave it unattended and the finish I get is AT LEAST equal to before. What really surprised me is that the parts seem to be very cool, if anything below ambient temperature. I didn't expect significant cooling from the air blast, only chip clearance. It is so nice not to have to mess with flood cooling (not an option in my house), and I am beginning to think that these mills can't supply enough power to the workpiece to heat it much when the air blast is running. Add that to the chips being cleared and you get good parts with no mess. A couple of pics below, with the door on and off. You can see my air pump on the shelf at the right.