We wrestled with the same exact issue in our shop. The first couple of projects that we did on the TM-1 were dry acrylic, so we didn't think much about it. Then the first coolant job ended in puddles everywhere. So we weighed our options of custom building an enclosure for the mill. So after figuring what it would cost to pay for a couple of day fab time for one of us to make what we needed the $700 or so dollars to buy from Haas seemed more cost effective. That way we could still keep all hands (myself and another guy) on programming and production since we were at a busy time in our schedule.
Some points to note would be...
1. Use alot of silicone caulking to seal the machine. This machine is a massive leaker.
2. Bend up a small sheet metal shroud to extend past the box holding the optical limit switch on the Y axis, you will lose lots of coolant at that spot.
3. If the machine doesn't have the table chip/coolant gaurds then get those as well they help a lot.
4. In front of the machine on the base casting the open area under the Y axis handwheel also needs to have a covering. We covered ours with thin gauge aluminum, leaving about a 1" opening at the bottom along the length. It may be usefull to mount it on a hinge if you plan on doing a large quantiy of work on the machine, cleaning that nook out can be a hassle if you don't hinge the plate.
5. The table drain hose is also an issue sometimes, if you can, I would reccomend drilling drain holes on either end of the table and let it drain vertically into the pan that way. The factory hole is just slightly above the bottom of the T-slots so the coolant will lay in the table till every is cleared manually.
6. I you plan on doing a lot of fixturing changes, I may also recommend getting a few lengths of the T-slot covers like they sell for Bridgeports. This will help keep the chips out of the slots and make the collant run a lot better.
7. On our machine I made a quick aluminum splash gard that is easily removed when not running coolant, that runs the length of the factory standard chip trough that drains into the coolant sump.
8. Some other ideas we have kicked around in our shop are adding endcaps to our shroud pans made from lexan or aluminum, but make sure if you do this keep in mind the clearances for the table moves.
One other note, at some point you may want to upgrade a get a larger coolant resivoir, the 5 gallon one is a bit under the need if you plan to run the mill over night a lot with the coolant.
All in all though we have had the machine on the floor making chips for the past 3 years and could be more happy with it.
Hope this helps.....