Production Line 
Definition
Production lines are used as work centers in the planning of flow manufacturing and repetitive manufacturing. A production line can be either a grouping of several processing stations or an individual processing station.
In the simplest case, it is sufficient to create two work centers for the entire production line.
However, you can also subdivide the line and create a work center for each processing station. You then select one of the work centers (generally the bottleneck work center) and enter it in the Production Line field in the production version. The system uses this work center for scheduling and capacity planning.
However, you can also use the "Line Design" component to subdivide the production line into individual elements and represent this structure as a line hierarchy .
Integration
If you want to subdivide a production line into individual elements (for example, processing stations) to better control the staging of materials and scheduling, you define a line hierarchy. In the process, you define a production line as the header of the line hierarchy and assign subordinate production lines or processing stations as elements. To do this, you must have previously created the production line and its processing stations as separate work centers with the appropriate work center categories. In the standard SAP system, a series of work center categories are predefined as examples. However, you can also create your own work center categories with your own descriptions depending on your enterprise's specific production structure (for example, line segment, station, zone).
If you do not want to subdivide a production line, it is sufficient to simply create the production line as a work center with the appropriate work center category.
The production line must previously have been entered in the production version.