I did an experiment with cutting aluminum which kind of worked, although there are things I would do differently next time.
I needed to cut a part which will go near a wood burning stove so it needs to be able to get hot and not be flammable so I decided to cut it from some aluminum.
I used on of the standard aluminum sheets from home depot that is about 1.5mm thick and I cut it in one pass at 500mm/min with a two flute router bit.
The machine seemed fine with that feedrate, but I should have cut a lot faster.
I had some issues with the router bit clogging with aluminum chips and then sort of melting its way through the metal leaving behind a jagged edge.
Next time I’ll try a single flue router bit and a higher federate (maybe 1,000mm/min) and I’ll use a bit of lubrication like WD40.
The jagged edges were relatively easy to clean up so this part will work fine, but I’d like to try again in the future. I think with a little tuning it should be possible to get nice clean cuts.
What if you used a cnc bit. I am sure you will find a shaft size to fit, and
these are designed to cut these materials
there isn’t much difference between a router bit and a CNC bit (other than the
CNC bits not having a standardized shaft size)
due to the maslow moving slowly, you want the slowest spindle speed and fewest
flutes you can get (and aluminum really had a tendency to melt onto your bit,
and when it does, stop cutting and see if you can clear it or if you have to
replace the bit)
Bar… I’ve cut a lot of aluminum. Oil steadily and consistently, it makes a huge difference between slicing through and burning through… and use a very sharp bit, carbide or better. You could probably cut thicker aluminum if you do it right.
Two things which may help. The alloy you are trying to machine is important. I never machined the 3003 aluminum sheets sold at Home Depot but if I had to guess, it is probably too soft. Soft aluminums cling to tools, clogging up the flutes (see your picture). 60-61 grades are harder and easier to cut because they offer more resistance to the cutting tools. It sounds counter intuitive, but the softer alloys are more malleable and want to grab the tools and suck them into themselves. This causes the ripple effect you experienced. A more rigid set up is required to counter this tendency, and give a more smooth straight cut. You may want to continue your experiment with 60-61 alloy aluminum. It is fairly common, and less “gummy” so it should give a better chip and straighter cut. The second issue is tool speed. Wood routers (5000 to 30000) rpm are way faster than what we ran in the shops. We would get best results with 1/8”-1/4” diameter High Speed Steel tools running at 1000-2000 rpm cutting a .001” chip per tooth. On my first (chain) Maslow, I used a cheap single-speed router 30000 rpm with a variable speed rheostat to slow the rpm’s down into the 1000-4000 range. The rheostats are in the $20-30 range on Amazon. I don’t know if these ideas will help, but they might be worth a shot.
No, I never cut aluminum on my chain Maslow, but if I were to try, I’d add an extra 30 lbs to the sled weights to keep the sled from bouncing, and keep my rpm’s in the 1000 to 2000 range.
