The evolution of a production planning system: A 10-year case study

This paper describes the evolution of a production planning system (PPS) from a simple work sequence generation tool to a useful, sustained scheduling system. Three stages of evolution are described. In the first stage, a Gantt chart sequencing tool was converted to a scheduler's information system. This change was driven by the need to support the scheduler's daily task. The second stage of evolution was caused by an MRP–ERP conversion. The integration and conversion increased overhead and complexity in the job task and hence the tool, including the transformation of the previously integrated dispatching/scheduling task into separate dispatching and scheduling activities. The third stage of evolution has been small continuous improvements driven by management reporting requirements. PPS was developed in 1996 and has been fully operational since January 1997. Two major insights are discussed in this paper: the implications of supporting the scheduling task versus work sequence generation, and the software design requirements for evolutionary change as the software is used in an ever-changing situation.