A production manager has often been confused to a producer or director , but they mean totally different things and perform different roles. 

A Unit Production Manager or (UPM) oversees the logistics of production. Each morning they mark arrival times for production reports, check in with each of the crew heads and make sure that load-in is handled correctly. If there are any errors, like parking for example, then they work with the production coordinator to fix them and update the production report for the line producer. Any paperwork that needs to get done or updated passes through the UPM’s hands, except for the Exhibit Gs, which are taken care of by the 1st Assistant Director’s department. If there are personnel issues on set, as in harassment or wage issues, it is recorded by the UPM and then they coordinate with the proper department to resolve the issue. You work directly under the Line Producer in running an efficient production. If things are running smoothly, it’s an easy job. However, any hiccups a shoot has are immediately felt by the UPM.” The Unit Production Manager is an administrative role that helps organize a film set and solves any problems that occur.

Am sure now you have understanding of who a production manager is and what a production does .