I just picked up parts which were cut from 1/2" aluminum plate. They were cut on a 4KW Mazak. The edge quality is really bad. There is a critical tolerance of +/- 0.003" called out on this part, which I was told they could hold with this machine. The cut quality alone would seem to prevent this. When I asked the shop about it they said that is the best they can do with 1/2" aluminum, which is at the the max thickness that they cut. Let me know what you think. Is this par for the course or am I being fed a line?
Sounds like you got conflicting information between sales and the shop floor. When cutting at the maximum capacity of the machine, I suspect the edge quality is going to suffer a bit. Aluminum is a pain to cut on a laser under the best of conditions because it's so reflective. I would concider water jet for the next parts, or have them laser cut oversize on a laser and run a final cleanup on a CNC mill.
From someone who laser cuts 6mm alum on a regular basis, that looks pretty normal to me. It can cut better on the 5kw Prima but not a huge difference. .003" is achievable though. But as you can see, it's a dimension measured across the peaks of those striations, and won't take into account the fact the wall isn't perfectly perpendicular to the surface.