We have an Accu-Bend machine in our shop. A machine like that is definitely good to have if your shop produces a lot of channel letters.
Previously we used software from a company called Arete that would create a cut path so channel letter returns could be routed out of a flat sheet of aluminum on a standard routing table. The path would incorporate all the notches needed for the returns. They sold a device where you could feed the routed return into it to make bends at specific points. The system worked very precise, but it wasn't a quick process. I think the Arete company went out of business.
The Accu-Bend machine does all the notching and bending of the returns automatically. I just wish it did a more neat, precise job at it. Some returns require a bit of clean-up work before attaching to a channel letter back or metal face. The machine seems to do best on larger letters and sans serif letter styles.
Not only do a growing number of communities require UL Listing on channel letter
signs, but they'll often also require the
sign company to have one or more employees carry Master Electricians Licenses and anyone doing the install work to have at the minimum a Journeyman's Electricians License. Our shop had to comply with those requirements to do any work down in Texas. Plus we had to get registered and licensed through the TDLR (Texas Department of Licensing and Regulation) and put the license number on our trucks. From time to time we have to send guys from our shop down to continuing education classes in the Dallas area.