I don't know anything about fabrication, but my spidey sense tells me that this won't happen for a while. It isn't a capability issue, it's a cost issue. There's obviously a tipping point, but cheap human labour has to be way ahead.

For robots, beyond the cost of powering and maintenance, repurposing has got to be a killer. Changes in material (plastics, to aluminum to composite...) has got to wreck havoc with automated assembly lines.