"Replicate itself" is a bit much. It's used on its own assembly line. Fanuc has done that for two decades. Here are Fanuc robots making more Fanuc robots.[1] Robots are pouring molten metal for casting, loading and unloading CNC machine tools, and making many of the parts. Then robots assemble the parts.
This is an ancient video about KUKA robot production [1]. While it's not very automated at all, some things are done with robots because no human has the required strength or precision.
Truth is, robots have been building robots since the 60s or so, long before I was born, and long before skynet was a fictional gleam in some author's eye.
[1] https://www.youtube.com/watch?v=pgzrkwXV-bY