Workers have finished their last shift at the car parts factory TRW in Resolven, near Neath, which is closing.
They clocked off at 1130 GMT at the factory, which employed 225 staff making steering parts.
TRW said Friday's closure was a "sad day". The company is transferring work to a sister site in Europe.
The US-based company made the announcement last summer, saying the plant had been making a loss for several years.
TRW spokesperson Lynette Jackson said: "This was a necessary, tough business decision.
"Our employees have gone through this difficult process with dignity and they should feel proud of their many years of excellent work."
Neath MP and Shadow Welsh Secretary Peter Hain has said previously that the workforce had been willing to make "tough and brave" cost savings which would have hit their earnings by more than 15% and possibly more if a guarantee had been given that Resolven had a future.
Unite union plant convenor Andrew James said last September that workers had made offers to the company to try to keep the factory open.
Deputy First Minister Ieuan Wyn Jones has called TRW's move "extremely disappointing".