SAP PP What is Work Center

A work center is a physical or logical production area which is used as a unit for scheduling and routing operations.

A work center is defined as being either labor or machine-constrained and since it may have multiple machines or employees they are considered as identical by means of capability to process the products allotted to that particular center.

A work center may execute multiple operations but in general the capacity requirements are tracked only at total work center level. Its definitions are flexible depending on the process and reporting capabilities and also organisation requirements.

Uses of data in work center –

Along with BOM and Routings, the work centers also one of the important master data in Production Planning and control system. They are used in task list operations such as Maintenance task lists, Inspection plans, Standard networks and Routings. Work centers is used in work orders and are created for Plant Maintenance, Quality Assurance, Production and for Project System as networks.

The data in work centre is used for –

  • Scheduling - The formulas entered in work center are helpful to calculate the duration of an operation.
  • Costing - The formulas entered in the work center enables to calculate the costs of an operation.
  • Capacity planning - The formulas used for calculating the capacity requirements and availability of capacity are stored in the work center.
  • Simplifying operation maintenance - Different default values are entered in a work center.

What is a work center in SAP?

A work center is useful for routing operations, production orders and is blended with other modules. A work center may be a machine, tool, device, person or a group of these.

It is a spatial area within the work system of an enterprise and an area where operations are performed.

A work center is used for defining persons and machines required in operations. It is used for modelling costs caused by operations and for specifying available capacity and scheduling structures.

A work center is plant-specific and created using the transaction code CR01. It is maintained by using the transaction code CR02 and consists the Basic data, default values, capacities, scheduling and costing views.

Functions of SAP Work Сenters in PP –

In SAP PP, the data in work center is used for operations –

  • Capacity Calculation
  • Scheduling of an Operations/Orders
  • Calculate Operation Costs

Integration with Other SAP Modules –

A work center is integrated with the other SAP modules like –

  • Controlling (CO)
  • Human Resource (HCM)
  • Plant Maintenance (PM)

Work center views –

The following are the views of a work center –

  • Basic data view – The basic data view manages the responsibilities and plan relations. It also allows to specify standard value keys for scheduling and capacity planning.
  • Default values view – To specify the default values for routing.
  • Capacities view - To specify the formula for capacity requirements calculation and capacity of work center.
  • Scheduling - To specify the formula for scheduling tasks.
  • Costing - The cost centers for work center and activity types.

Work center categories –

The work center category was maintained by using the transaction code OP40. These categories allow control over a work center usability in routing. Some kind of work center are used only in specified routing plan types.

The following are the examples of work center categories –

  • Machine
  • Machine group
  • Labor
  • Labor group
  • Plant maintenance etc.

Work center capacity –

The capacity objects are maintained in work center capacity view. Where a capacity is defined as a service that is provided by machines or persons for some time.

A work center have various capacities and the capacities like –

  • Machine capacities
  • Spare capacities for rush orders
  • Personnel capacities etc. are assigned to a work center

The capacity calculation in SAP –

  • Available capacity –
    Generally, the SAP work center capacity indicates the available hours of machine or labor resource. These available hours do not include the break or halt hours. For example, assume a machine available for production in plant from 9 am to 6 pm and break is 1hr.
    Then the available capacity is equal to Total available hours - break hours
    Available capacity = 9 hrs – 1 hr
    Available capacity = 8 hrs
  • Required capacity –
    The require capacity means the time taken in order to produce a specified quantity of product. For calculating it, SAP consider the operation time and capacity formula.
    For example, in a manufacturing unit, the usage of a machine maintains the things like labor time, machine and setup time.
    • Labor time= 60 mins
    • Machine time = 60 mins
    • Machine set up time = 30 mins
    • Base Quantity = 100
    • Production order quantity = 300

So the capacity calculation for that machine is as follows -

Required capacity = machine time * production order quantity / base quantity.

Required capacity = 60 mins * 300/100.

Required capacity = 60 mins * 2.

Required capacity = 180 mins.

Here is also a concept of number of individual capacities. This is availability of number of individual machines with similar capacity. When it calculates the required capacity, it divides number of individual capacities in a formula. When it calculates the available capacity, it multiplies number of individual capacities.

The formula defined as follows –

Machine time * Production order quantity / Base Quantity * No of splits.

So, the required capacity is calculated as –

Required capacity = machine time * production order quantity / base quantity * 2

Required capacity = 60 * 300/100 * 2

Required capacity = 18000 /200

Required capacity = 90 mins.

Structure of work center –

The structure of a work center consists 3 main levels. They are –

  • Department
  • Planning area
  • Work center

These work centers are internal or external. For example, external work center is contractor. In ancient days, a work center contains electrical, instrumental, mechanical and so on which are replaced as team 1, team 2, team 3 and so on in modern days.

A work center category that is defined in customizing the work center determines the data to be maintained in a work center.

The data is organised thematically together in screens and screen groups. Examples of such screen or screen groups are –

  • Basic Data
  • Assignments (to cost centers, Human Resource Management System (HR))
  • Capacities
  • Scheduling
  • Default values
  • Hierarchy
  • Technical data

Maintaining work center capacities –

The capacities can be added to a work center in capacity category form. The capacity categories are created as follows –

Production -> Basic data -> Work center -> Capacity planning -> Define capacity category.

While creating a work center it is possible to assign capacity categories in capacity view.

The capacity categories are also added to an existing work center by using capacity view.

Work center capacity header –

A work center capacity header is defined and maintained for the combination of Plant, Work center and capacity header.

The work center capacity header can specify –

  • Capacity planner group
  • Factory calendar ID
  • Base unit of measure (e.g. H)
  • Daily work start and finish time
  • Total length of daily breaks
  • Capacity utilization rate
  • No. of individual capacities (e.g. various work centers can be grouped into one capacity)

In the work center capacity header it also possible to specify relevance for limited scheduling, overload percentage and long-term planning, use for different operations.

Maintaining shift sequences –

Maintenance of shifts, Break plans and Shift sequences are done in the transaction code OP4A.

  • The Break plan is defined as a table comprising start time, end time and break length.
  • Shifts are defined as a table with start time, finish time and breaks.
  • Shift sequences are defined by assigning shift names to weekdays.

Shifts, break plan and shift sequence are assigned to a grouping. The grouping is assigned to the work center capacity header.

Pooled capacities –

The pooled capacities are used for modelling capacities that are used by different work centers. The pooled capacities are created by the transaction code CR11 i.e., in transaction code CR11 check pooled capacity box. Then pooled capacity is assigned to work center in the capacity view of the work center. The pooled capacities is displayed from the capacity view but are not maintained from capacity view.

Scheduling in SAP Work Centers –

Generally, the scheduling means calculation of start date or time and end date or time of an operation which is conducted in a work center based on a requirement date.

The details required for scheduling an operation or machine are -

  • Formula for scheduling in work center scheduling view.
  • Requirement date/time from an order.
  • Operation time from routing.
  • Inter-operation times from routing.

The SAP system do backward scheduling starting from the requirement date or time scheduling the order.

The "inter-operation times" specifies queue time, wait time and move time.

  • Queue Time - The time raw material or components need to wait before they are processing in a machine.
  • Wait Time - The time that a material should wait after its processing in a work center.
  • Move time - The time needed for material move to next work center for further processing.

Costing in SAP Work Centers –

The SAP system calculates activity cost based on the information –

  • Costing formula in a work center.
  • Operation time in a routing and an order.
  • Activity rate defined for the cost center which is assigned to the work center.