A miter fod bit on a cnc could do it. We do this on dibond sintra and plexi all the time
Could you give a little more detail on the tool and how a miter bit can put a bend on 18th inch aluminum.
V-Groove (with router or V-grove saw blade) backside of aluminum, bend, tack weld. pretty durned sharp corner
Just ask around for someone that has a brake that will work up to 16ga. Most brakes should be able to handle that piece of aluminum. There might be a tiny radius. I would find a metal shop. Not a HVAC shop because they can bend it but they bend for their own needs. A metal shop will have more knowledge of what they can do and what the end product will be like.
for this scenario, I would probably just LORD's the face 1/8" alum to some sharp corner aluminum angle