When demand is dependent on multiple materials, managers use a concept known as materials requirements planning, or MRP, to determine demand for lower level items. MRP is a logical approach to determine the number of parts, components, and material needed to produce each end item. It also provides the time schedule specifying when each of these materials, parts, and components should be ordered or produced. | Chapter 16 Materials Requirements Planning Material Requirements Planning (MRP) MRP Logic and Product Structure Trees Time Fences MRP Example MRP II and Lot Sizing OBJECTIVES 2 2 Material Requirements Planning Materials requirements planning (MRP) is a means for determining the number of parts, components, and materials needed to produce a product MRP provides time scheduling information specifying when each of the materials, parts, and components should be ordered or produced Dependent demand drives MRP MRP is a software system 3 3 Example of MRP Logic and Product Structure Tree B(4) E(1) D(2) C(2) F(2) D(3) A Product Structure Tree for Assembly A Lead Times A 1 day B 2 days C 1 day D 3 days E 4 days F 1 day Total Unit Demand Day 10 50 A Day 8 20 B (Spares) Day 6 15 D (Spares) Given the product structure tree for “A” and the lead time and demand information below, provide a materials requirements plan that defines the number of units of each component and when they will be needed 4 4 | Chapter 16 Materials Requirements Planning Material Requirements Planning (MRP) MRP Logic and Product Structure Trees Time Fences MRP Example MRP II and Lot Sizing OBJECTIVES 2 2 Material Requirements Planning Materials requirements planning (MRP) is a means for determining the number of parts, components, and materials needed to produce a product MRP provides time scheduling information specifying when each of the materials, parts, and components should be ordered or produced Dependent demand drives MRP MRP is a software system 3 3 Example of MRP Logic and Product Structure Tree B(4) E(1) D(2) C(2) F(2) D(3) A Product Structure Tree for Assembly A Lead Times A 1 day B 2 days C 1 day D 3 days E 4 days F 1 day Total Unit Demand Day 10 50 A Day 8 20 B (Spares) Day 6 15 D (Spares) Given the product structure tree for “A” and the lead time and demand information below, provide a materials requirements plan that defines the number of units of each component and when they will be needed 4 4 LT = 1 day First, the number of units of “A” are scheduled backwards to allow for their lead time. So, in the materials requirement plan below, we have to place an order for 50 units of “A” on the 9th day to receive them on day 10. 5 5 Next, we need to start scheduling the components that make up “A”. In the case of component “B” we need 4 B’s for each A. Since we need 50 A’s, that means 200 B’s. And again, we back the schedule up for the necessary 2 days of lead time. B(4) E(1) D(2) C(2) F(2) D(3) A Spares LT = 2 4x50=200 6 6 B(4) E(1) D(2) C(2) F(2) D(3) A 40 + 15 spares Part D: Day 6 Finally, repeating the process for all components, we have the final materials requirements plan: The McGraw-Hill Companies, Inc., 2001 7 7 Master Production Schedule (MPS) Time-phased plan specifying how many and when the firm plans to build each end item Aggregate Plan (Product Groups) MPS (Specific End Items) 8 8 Types of Time Fences Frozen No schedule changes allowed within this window .
