Transcript Chapter 11
Chapter 13 Material Requirements Planning © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e MRP Computerized inventory control & production planning system Schedules component items when they are needed - no earlier and no later © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 2 2 When to Use MRP Dependent and discrete items Complex products Job shop production Assemble-to-order environments © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 3 3 MRP Inputs & Outputs Master Production Schedule Product Structure File Material Requirements Planning Inventory Master File Planned Order Releases Work Orders © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e Purchase Orders 2000 by Prentice-Hall, Inc Rescheduling Notices Ch 13 - 4 4 MRP Inputs Master production schedule Product structure file Inventory © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e master file 2000 by Prentice-Hall, Inc Ch 13 - 5 5 Master Production Schedule Drives MRP process with a schedule of finished products Quantities represent production not demand Quantities may consist of a combination of customer orders & demand forecasts Quantities represent what needs to be produced, not what can be produced © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 6 6 Master Production Schedule MPS Period Item 1 2 3 4 5 6 7 8 Clipboard 86 93 119 100 100 100 100 100 Lapboard 0 50 0 50 0 50 0 50 Lapdesk 75 120 47 20 17 10 0 0 Pencil Case 125 125 125 125 125 125 125 125 © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 7 7 Product Structure Tree Clipboard Clip Assembly (10) Board (1) Rivet (2) Top Clip (1) Bottom Clip (1) Pivot (1) Spring (1) Sheet Metal (8 in2) Sheet Metal (8 in2) Spring Steel (10 in.) Iron Rod (3 in.) © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e Level 0 Pressboard (1) 2000 by Prentice-Hall, Inc Level 1 Finish (2oz.) Level 2 Level 3 Ch 13 - 8 8 Indented Bill of Material LEVEL 0----1----2----3--2----3--2----3--2----3-1---1----2---2-© 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e ITEM Unit of Measure Clipboard Ea Clip Assembly Ea Top Clip Ea Sheet Metal In2 Bottom Clip Ea Sheet Metal In2 Pivot Ea Iron Rod In Spring Ea Spring Steel In Rivet Ea Board Ea Press Board Ea Finish Oz 2000 by Prentice-Hall, Inc Quantity 1 1 1 8 1 8 1 3 1 10 2 1 1 2 Ch 13 - 9 9 Inventory Master File Description Item Item no. Item type Product/sales class Value class Buyer/planner Vendor/drawing Phantom code Unit price/cost Pegging LLC © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e Board 7341 Manuf. Ass’y B RSR 07142 N 1.25 Y 3 Inventory Policy Lead time Annual demand Holding cost Ordering/setup cost Safety stock Reorder point EOQ Minimum order qty Maximum order qty Multiple order qty Policy code 2000 by Prentice-Hall, Inc 2 5,000 1 50 25 39 316 100 500 100 3 Ch 13 - 13 10 Inventory Master File, Con’t. Physical Inventory On hand Location On order Allocated Cycle Difference © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 100 W142 50 75 3 -2 Usage/Sales YTD usage/sales MTD usage/sales YTD receipts MTD receipts Last receipt Last issue Codes Cost acct. Routing Engr 2000 by Prentice-Hall, Inc 1,100 75 1,200 0 8/25 10/5 00754 00326 07142 Ch 13 - 14 11 Inventory Accuracy 1. Maintain orderly stockrooms 2. Control access to stockrooms 3. Establish & enforce procedures for inventory withdrawal 4. Ensure prompt and accurate entry of inventory transactions 5. Take physical inventory count on a regular basis 6. Reconcile inventory discrepancies in a timely manner (use cycle counting) © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 15 12 The MRP Matrix Lot size: LT: Gross requirements Scheduled receipts Projected on hand Net requirements Planned order receipts Planned order releases PD 1 2 3 4 5 6 7 8 9 Item name or number identifying scheduled item LLC low-level-code; lowest level at which item appears in a product structure © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 16 13 10 Parts Of MRP Matrix Lot size order multiples of this qty; can be min/max qty LT (lead time) time from order placement to receipt PD (past-due) orders behind schedule Gross requirements demand for item by time period © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 17 14 Scheduled receipts quantity already on order & receipt date released orders become scheduled receipts Projected on hand expected on-hand inventory at end of period Net requirements net amount needed after on-hand adjustments Planned order receipts net requirements adjusted for lot-sizing Planned order releases planned order receipts offset by lead time © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 18 15 Capacity Requirements Planning (CRP) Computerized system that projects load from material plan Creates load profile Identifies © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e underloads and overloads 2000 by Prentice-Hall, Inc Ch 13 - 25 16 Capacity Terms Load profile Capacity Utilization Efficiency Load Load percent © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 26 17 Capacity Requirements Planning MRP planned order releases Routing file Capacity requirements planning Open orders file Load profile for each machine center © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 28 18 Initial Load Profile Hours of capacity Normal capacity 1 © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2 3 4 5 6 Time (weeks) 2000 by Prentice-Hall, Inc Ch 13 - 31 19 Adjusted Load Profile Hours of capacity Work an extra shift Overtime Push back Pull ahead Push back 1 © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2 3 4 Time (weeks) 2000 by Prentice-Hall, Inc 5 6 Ch 13 - 32 20 Remedies for Underloads 1. Acquire more work 2. Pull work ahead that is scheduled for later time periods 3. Reduce normal capacity © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 33 21 Remedies for Overloads 1. Eliminate unnecessary requirements 2. Reroute jobs to alternative machines or work centers 3. Split lots between two or more machines 4. Increase normal capacity 5. Subcontract 6. Increase the efficiency of the operation 7. Push work back to later time periods 8. Revise master schedule © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 34 22 Problems with MRP Material requirements plan is first; capacity is an afterthought MRP assumes fixed lead times Excessive © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e reporting requirements 2000 by Prentice-Hall, Inc Ch 13 - 43 23 Manufacturing Resource Planning (MRP II) Extension of MRP Plans all resources needed for running a business Variations include Service Requirements Planning (SRP) Business Requirements Planning (BRP) Distribution Requirements Planning (DRP) © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 38 24 MRP II Modules Forecasting Customer order entry Production planning / master production scheduling Product structure / billof-material processor Inventory control © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e Material requirements planning Capacity planning Shop floor control Purchasing Accounting Financial analysis 2000 by Prentice-Hall, Inc Ch 13 - 39 25 Prospects for MRP/MRP II Coordinates company strategy among different functional areas Responds quickly to what-if? questions at various levels of detail BOM processors, purchase modules, & customer order entry are standard requirements for Manufacturing Information Systems Monitors design & vendor quality, & customer service Builds trust, teamwork, & better decisions Cash-flow planning & profit/cost projections © 2000 by Prentice-Hall Inc Russell/Taylor Oper Mgt 3/e 2000 by Prentice-Hall, Inc Ch 13 - 44 26