Sensing 300A on a SMD PCB

Yes, it can, idiot. IF you had read the page, you would have seen that it can CUT 1/4" Aluminum. It most certainly can cut a couple mm of Copper, and if it does not on the first pass, simply burn again until through. The path is programmed in quite precisely.

Get a clue.

It can make marks in the surface (only) of anodized aluminum by affecting the anodizing dye. You can mark steel but only if you pre-treat it with a special material. No way will it cut anything like copper.

I have a 40W CO2 CNC laser- it's actually fairly underwhelming. Air assist on the nozzle is required for cutting even acrylic.

Look at LPKF's offering$ for what will actually cut thin copper.

--sp

No. It can CUT completely THROUGH 1/4 thick Aluminum plate, asshole.

The power setting for etching a product label and that for CUTTING are several tens of Watts apart.

you have got to be kidding, 40W can barely cut 1/4 plastic and you expect it to cut 1/4 aluminium, that is not only reflective but an excellent heatsink?

you need 100x that power to cut aluminium half that thick

-Lasse