In Engpsh, you could say "working hours at the factory" to refer to the time when people are expected to be working at the factory. You could also use the phrase "factory shift" to refer to a specific period of time during which a group of workers is scheduled to work at the factory. For example, you could say "I work the evening shift at the factory" to indicate that you work during the evening hours at the factory. If you want to specify the exact times that the factory is open for business, you could say something pke "The factory is open from 8 am to 5 pm Monday through Friday."