No, manual labour is actually at least 'quite probable' (because it's a factory and I imagine that most people working there work manually). I see you learned some Russian, where работать is a basic verb. The noun "robota" in Polish works mostly as a colloquialism for any work, and place of work, then you have something like "roboty budowlane" (construction works) but it has to be plural then. And also in contexts like: Get to work! Weź się do roboty! I don't think there's any verb created from it, not even a colloquial one. "Robotnik" is indeed a standard word for a guy working with his hands.