Understanding MRP and MRP II Systems for Manufacturing
MRP Systems
MRP techniques provide a solution to control and coordinate materials, which Hall noted are effective when data is accurate.
The MRP system is defined as a planning system for manufacturing components. To perform, MRP requires information from three primary sources, with data generated by specific subsystems:
- Master Production Schedule (MPS)
- Inventory Status
- Bill of Materials (BOM)
From this data, the explosion of needs is constructed—the process by which external demands for final products are translated into specific manufacturing and procurement orders.
Key Features of MRP
- Product-oriented
- Prospective approach
- Does not account for capacity constraints
- Integrated database
Conditions for MRP Implementation
- The final product is complex.
- The cost of the final product is high.
- Processing time for raw materials and components is high.
- The production cycle of the final product is long.
- The need to consolidate material requirements for various products.
- Manufacturing occurs in blocks.
Benefits of MRP
- Decrease in inventory levels.
- Improved customer service levels.
- Reduction in overtime and temporary employment.
- Decreased outsourcing.
MRP II
MRP II planning goes beyond materials and quantities; it includes all resources necessary for production, as well as the economic and financial dimensions of the system.
Mechanism and Workflow
The system processes demand data to produce a sales plan, which is associated with a production plan. This information creates an aggregate production plan, serving as input for medium-term aggregate capacity planning to determine feasibility.
Once the aggregate production plan is verified, it serves as input for the master production schedule, lot sizing, and deferment. From the master production schedule, capacity is assessed. Once accepted, the system develops the material requirements plan, the viability of which is tested through detailed capacity planning.
Planned orders for components acquired externally serve as input for supplier programming and purchasing management. Components manufactured internally serve as input for workshop management, which schedules operations for each order based on priorities.
Levels of MRP II
MRP II consists of five levels: four for planning and one for output control.
The Role of Kanban
The heart of the system is Kanban, which tracks tasks in progress and ensures product flow to a workstation only when an order has been issued for that specific position.