John Doe wrote:

I'm not very hopeful in getting a cheap 3018 CNC to cut aluminum well,
but...
Soft aluminum is hard to cut well. And, if it gets even MODERATELY warm, it
is MUCH worse. So, here are some things to consider.

Take lighter cuts than you might be able to get away with, but keep the
feedrate up. That prevents heat from developing in one spot, it spreads the
heating all over the work.

Flood coolant or any other coolant tends to keep the workpiece cool, that
keeps the work metal stiff and allows the cutter to CUT, rather than MASH to
work.

Use climb milling (opposite direction to what was shown in the YouTube
video). Climb milling has the cutter diving into the uncut work, rather
than going into the just-cut material and working up a ramp until cutting
pressure drives the edge under the surface. Conventional milling causes
increased heat, excessive cutter wear, and poor surface finish due to re-
cutting and welding of chips. Climb milling avoids these issues, but has
the problem it works against the backlash in the machine. So, climb cuts
need to be made shallow on machines with a lot of backlash.

If you need to make a slot, use a cutter smaller in diameter than the slot
width. Take several passes down the middle until at full depth, then move
the cutter over and climb mill the sides to widen the slot to final
dimension.

If the metal does not need to be bent later, 2024 is great, and 6061 is
good. If you need to bend the sheet after milling, then either soft 5052 or
3003 can be used, but these require careful milling to avoid the heat
buildup and problems with tearing or fouling the cutter.

I use almost exclusively 1/8" solid carbide 4-flute end mills for all
aluminum panel machining. For the larger sizes, I use M-42 or M-57 cobalt
HSS, which is 100X better than plain HSS, and only costs a few $ more. The
eBay HSS tools out of China that come in the blue plastic tubes are AWFUL
crap, and I would not use them.

Jon