I just got a printer with swappable heads that can do FDM 3d printing, milling, and laser engraving. Presumably questions relating to the first are in scope here; how about the others? Or how about questions about the intersection? For example, a question about how best to design a model that can be produced either by FDM or milling.
Various proposals covering the 3D printing space went through many iterations including a broader site about "Personal Manufacturing" and another for "Digital Fabrication." This is another variation on that scope.
3D printers are going to become increasingly capable and integrate features we haven't even imagined. So as 3D printers start to cross over into other related areas, as long as the questions are not too far outside the target audience of this site, I would allow them.
This is one of those times where I'd say it's not the "name" that defines this site, but the intentions of the community that built it. So unless (until) there arises a field of questions incongruous with the audience of this site, I wouldn't be too quick to break out the Oxford English Dictionary to define its scope.
Essentially, I would err towards keeping these questions and let their longer track record decide if they belong.