It still would mean a company cannot really offer to do repairs for you, wouldn’t it? They’d have to be able to prove that none of their employees looked at the design documents, ever.
CC licenses aren't viral in that way. I can write a CC BY-NC instruction and repair manual for a Ford Prefect, and a professional mechanic can use the information contained within to help them fix Ford Prefects. The NC aspect of the license just means they can't sell the repair manual, charge for entrance to a dramatic reading of the repair manual, etc: it doesn't apply constraints beyond an All Rights Reserved design doc from any other manufacturer.
So if Ford were to publish full schematics for the Perfect under a CC-NC license would it be permissible for a third party to use that in order to offer (commercial, for profit) manufacturing and assembly? Honest question, because I'm not clear where the line for these printers sits.
Off the top of my head (keeping in mind it's years since I last researched this), patent and trademark law are what prevents people cloning someone else's machine from the spec. So unless there are patents, I don't think you'd have a problem.
