A study of replanning frequencies in a material requirements planning system

A simulation model is used to examine the effects of different replanning intervals in a material requirements planning (MRP) system. Replanning frequencies of monthly, twice monthly, weekly, twice weekly, daily, and twice daily are simulated in an MRP environment in which timing changes can occur in the master production schedule. The replanning frequencies are evaluated on the basis of end-item service rate, inventory value, and the number of open order change notices. The results suggest that inventory may increase with more frequent MRP replanning and that the widely-accepted practice of making weekly MRP runs may not always be the best alternative.