Kannst Du (oder ein deutscher Muttersprachler) erklaeren, was das bedeutet und beinhaltet?

He probably means: have a good day (shift) but I wouldn't say have a good shift, because of the double entrendre.
Maybe just "have a good day" would be the best?

In a factory, at the beginning of a (working) shift the lead wishes the team: Schöne Schicht! Something like enjoy the work or what else.

OK, so Irish is on the right track. As a life-long factory worker in the U.S. and Canada, I've never heard "have a good shift." In fact, I've seldom heard anyone wish anyone else a good day at the beginning of a shift. "Have a good day" is something one most often says in parting.

But what is your context? If you're translating a scene from a German factory, then by all means: "have a good shift" would be the way to go.