Im not sure that that 30mm thick alu can be laser cut, it would require a huge amount of power. The thickest I have heard of is 20mm and that was done with 7KW. We have a 3KW CO2 and its limit would be 6 or 8mm alu but it doesnt have an ATFR so we dont cut alu with it. We dont want to risk damaging the optics and output coupler with a back reflection. When you get above the 7KW range these lasers tend to be used for welding rather than cutting. If I get a chance I will speak to our laser service engineer today and see if he has heard of anyone cutting 30mm alu. Plasma or water jet would be the way to go then machine the edges if required.