I have for years used my table saw to cut up 1/4 aluminum easily and 3/8 & 1/2 a little less easily. When I had a radial arm saw using the same blade types I cut alum. there also.
I use carbide tipped blades with a triple chip tooth design and 0o rake. 60T x 10" diam.
Thinner aluminum may chatter a bit so I cover it, not the cut but right next to it, with a piece of wood. As you advance the metal rides up on the blade and then drops when the saw cuts it. With the wood clamp the riding up is controlled.
I have actually cut 1" but that really needs 2 people. One to control the piece and the other to spray the cut line with something like WD40 or any suitable lube. Just be darn sure that YOU have control of the part.
I also cut brass with the same blades.
As suggested wear hearing AND GOOD eye protection or you will pay for it. Maybe goggles AND a face mask. It is noisy and the chips may cut and do damage.
I have also routed aluminum for easing the sharp edges to a nice radius.
Just do the cut in more than one pass and again make sure YOU have control.
Advance slowly or you will load the cutter.
I clamp the part to the table, route the part as far as I can, shut of the router, move the clamps and then go again.
I use those blades also for cutting Plexiglass, Lexan and most plastics. THey do a good job. For thick , 3/4" or over, plastics you need fewer teeth and a slower feed although it will cut but may heat up and melt.
For shapes a bandsaw is a great tool. We used to use a skip tooth, 4 tpi for over 1/4. For thinner material that was a bit rough so would change to a somewhat finer tooth. To long ago for me to remember and I no longer have a bandsaw for all the details
Of course hacksaws, files, wire brushes, sanders all have their place too but more for the finishing.