I need to CNC cut 4mm thick aluminum in a pattern roughly 2ft x2ft. Does anyone know if the CNC machine will do that?
Indeed it will! O-flute, two, and 3 flute are all good options. There’s finishing bits and roughing bits in 3 flute.
You’ll need to make multiple passes to get it to do that. If you can setup to drill as much as possible (including pilot holes), that’ll greatly improve your results. It drills like a dream. Drill as much as you can. For milling, you’re going to be running at super slow spindle (I’m often down in the 6k range) and feed speeds. I can lookup what I’m using currently if you need it.
I know what I’m about to say is heresy, buy your own 1/8" collet (DO NOT USE THE SHOP’S COLLET FOR THIS) and short-chuck something like a 1/8" drill bit in it, so you only have 1/2" of the bit exposed. Having the collet grab on the flukes tears up the collet over time, but produces nice results, quickly, predictably. I’ve saved the money I spent on the collect after a few sessions of not breaking endmills. Make sure to get the eccentric tight.
I’ve had mixed luck with 1/8" o-flute endmills, they work, but it takes a while to get them dialed in, on my to-try list is using a 1/4" endmill, and see if that produces more stable results. But I have to use 1/8" endmills for most of my work because of the size of my features.
The compressed air helps out a ton, it’s made it so I don’t need any other kind of cooling while cutting. The shop air is rather “wet”, but that’s actually an advantage for metal cutting, it’s slowly having water dripped on it. Be sure to watch where the metal dust/shaving are flying. They get everywhere, quickly. Have the shop vac with the long hose out + the dust collection system. Cleaning up the metal shavings before they spread will save you a ton of time in cleanup.
For fixturing, I’ve had decent luck with the blue tape + superglue method. For something like you’re describing, another thing I’d suggest looking through the scrap wood, and finding a few pieces of plywood to put on each side, then put fiber nails in to anchor it.
If your raw stock needs to be super aligned, or if you’re moving/flipping your stock between cuts, let me know and I’ll share my thoughts on the best way to fixture for that.
What @zach said. If you interpolating your holes. Use a drill toolpath on center before you interpolate. It helps to remove the center of smaller holes. If you don’t cut the center. The plug at the bottom sometimes has a tendency to break your bit because it is oblong shaped and exiting the hole.
Interesting point- we’re switching to the Atlas Copco with an integrated dryer. It won’t be “wet” anymore. We can maybe add a onedrop system to mist a bit?
Nice!
I ran out of alcohol recently. I was able to get gel hand sanitizer locally. I mixed 1/3 alcohol and 2/3 gel hand sanitizer. The viscosity is higher. I had to open the needle valve on the mister a bit more. I found the concoction to give me better results with cooling and lubricity.
The air nozzle has a oil-in, and we saved the tubing for it (should be in the drawers) to use a misting bottle, so we don’t have to buy any hardware, just enable what we have.
I’m just a little nervous about using alcohol, I don’t want to catch anything on fire. 
I do understand it’s a great coolant, but we also need to make it mildly idiot proof. For me, heat isn’t hasn’t been a huge issue, I’m not cutting through super thick material, so I’m not going to worry about it. I was more stating, “If you’re working with the air, don’t worry about it spitting out water. You haven’t broken anything.”
If we changed anything about the air, I’d like to be able to maybe punch a hole in the top of the shoe that we can plug or insert the air nozzle. Coming in from the side has caused me issues a few times. I’d rather have a better spot for the air to come in. Come to think of it, if the shop doesn’t do it, I might just buy my own shoe so I can… They are pretty cheap, right?
^^^^ 100% yes. I think the shoe is something that could almost be considered a consumable. Different styles support different projects. They are cheap enough, and having the proper setup really helps with clean up. The 2 port magnetic shoe doesnt do much for me when slab flattening, but the red or white shoes are a dream. To each their own.
If we can get the solenoid set up. The alcohol only runs during your cut. If it is a long cut. I would be cognizant about how much alcohol is being misted into the air. The alcohol only matters when you get thicker. I would say 1/8" or thicker
What sort of alcohol? We don’t have any way to contain the fume after evaporation. I don’t think isopropyl (rubbing alcohol) is viable as it’s too toxic. Ethanol isn’t the same sort of toxic but it still seems problematic to just vent it into the workshop.
70% isopropyl. Lately I have been running a 1/3 isopropyl with 2/3 gel hand sanitizer. The evaporation is not a big deal.