The PEGS Scheduling System: A Case Study

The PEGS (Production and Environmental Generic Scheduler) program is a new generic scheduling program for manufacturing companies. It includes sort and search algorithms and can operate on the basis of elapsed time or economic values. Program performance is compared to a series of published benchmarks. The case study presented here illustrates the use of PEGS for a flow shop configuration at a local company manufacturing agricultural net-wrapping. The effects of batch size on makespan were studied using a conventional elapsed time basis. The study was then extended to consider optimising for minimum operating costs and including consideration of cost of waste arising from product changes. The program was modified to cope with operating practice in the company. Test results are presented illustrating how makespan and machine utilisation vary with job batch sizes, and the effects on an economic objective and makespan when environmental costs are included.