A modified MRP for a production system with the coexistence of MRP and kanbans

This paper deals with MRP treatments of the coexistence of MRP and kanban systems. In practical applications, MRP and kanban can both exist in a factory. When a production system contains parts managed by an MRP system and parts managed by a kanban system, MRP needs to have a special way of dealing with those parts managed by the kanban system in order to provide accurate gross demand data for the MRP system. A modified MRP for treating parts ordered through kanbans with the coexistence of MRP and kanbans is proposed. Along with two other existing methods (one by Karmarkar and another by a major tractor company), three methods are compared in a GPSS simulation study. Empirical results regarding inventory and shortages from the simulation study showed that both the proposed modified MRP and Karmarkar’s methods of dealing with parts ordered by kanbans performed quite well. This research study suggests two effective lot-sizing rules to be used in MRP part explosion for kanban-controlled stages of a production system in which some stages are controlled by kanbans and other stages by MRP releases. The simulation study established empirical evidence for the effectiveness of these two lot sizing rules.