An external development of sub-assemblies is a problem in the control of the Supply chain. The concept of SAP ERP assumes that a sub-contractor is able to accomplish all activities in time. But a sub-contactor might have limited capacities as well and his own orders might compete for the same resources. Moreover, there can be restrictions concerning transport and other constraints.

Initial situation

Individual manufacturing levels can be realized by sub-contractors. In cases of a short term reaction to customer's requests the same questions appear:

Similar questions as for the in-house manufacturing planning are asked. The schedulers are using OR Soft Manufacturing Workbench for planning the production on the premises in order to simulate fast action alternatives and to compile a solution for a short term delivery inquiry. The subcontracting deals with releasing orders without caring about details like available capacities and availability of ordered materials. So it also might be a good idea to use OR Soft Manufacturing Workbench for planning subcontracting.

Problem description

The planning problem can be describes as follows:

Each project needs the answer to the question whether the individual demands can be satisfied in time and volume at an external processing capacity.

Method of resolution

Itís possible to provide schedules for subcontracting as well as for self-produced manufacturing. In OR Soft Manufacturing Workbench the order of subcontracting is linked to schedule and parts list. Thus, capacity-relevant "production orders" develop. These "production orders" are evaluated in a planning map, where also all manipulations of the providing elements are performed. In the background the system ensures that the correct transactions are implemented in SAP ERP.


In the upper table of the picture an overview of all projects is shown. Besides the master data of a project there are status messages summarized on a weekly basis. Exceptions are here shown as red crosses. These messages signal the overflow of the weekly capacity or missing materials provided. In order to inform about the exceptions, two detailing levels are available. In the first level (middle window in the picture) a compression to the individual days of delivery is accomplished. With the value that is aggregated by the day (in the picture, 11049 pieces on Tuesday) you can indicate the individual underlying components (lower window in the picture). In these two windows further exception messages are displayed and procedural instructions for the recovery of the conflicts (e.g. rescheduling) are suggested.


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