DDMRP Capacity Scheduling
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This document discusses demand driven capacity scheduling and execution. It explains that demand driven operating methods seek to protect the flow of both relevant information and materials through the use of buffered decoupling points. These decoupling points establish independent planned and scheduled horizons, and resupply signals are created based on the available stock status of each buffer. The document also discusses placing control points between decoupling points to better control lead time zones and reduce required stock, and using buffer boards to visualize and protect schedules at control points from upstream variability.
DDMRP Capacity Scheduling
- 1. Demand Driven Capacity Scheduling and Execution Chad Smith Partner, Demand Driven Institute Co-Author Orlicky’s Material Requirement Planning 3/E Co-Author Demand Driven Performance – Using Smart Metrics All material and © copyright Demand Driven Institute 2013, all rights reserved
- 2. Planning and Scheduling is Harder Than Ever • The Manufacturing and Supply Chain landscape is more volatile than ever – the bullwhip is alive and well in today’s environment • Customer Tolerance Times have decreased substantially relative to the time it takes to procure, manufacture and distribute items • Product variety, options and complexity has put tremendous pressure on planning and scheduling systems • FLOW is the critical link between service, asset utilization and ROI All material and © copyright Demand Driven Institute 2013, all rights reserved
- 3. The Demand Driven Operating Method • The protection of FLOW is paramount • ROI is directly proportionate to the speed of flow of relevant materials and information • Demand Driven operating methods seek to protect the flow of both relevant information and materials All material and © copyright Demand Driven Institute 2013, all rights reserved
- 4. DDMRP and Capacity Scheduling • DDMRP has Implications for Capacity Scheduling • Advanced Session Webinars • Download the paper on DDMRP Master Scheduling for more information All material and © copyright Demand Driven Institute 2013, all rights reserved
- 5. DDMRP Scheduling Basics DDMRP uses buffered “Decoupling Points” to establish independent planned and scheduled horizons. DDMRP creates resupply signals based on the “available stock” status of each buffer. This gives prioritized sequence based on actual need. On-the-floor priority is then determined by the real time buffer status of the decoupling points that the open orders are feeding.
- 6. When Will we Need More Scheduling Capability? • When the use of better shop floor scheduling will compress lead times and reduce variability so that make item stock buffers can be reduced. • When no decoupling point can be inserted before the shipping point. (Make or Configure to Order) • Mixed-mode operation All material and © copyright Demand Driven Institute 2013, all rights reserved Advanced Topics Webinar 3
- 7. An Mixed-Mode Example In this case better scheduling and execution is required to synchronize and prioritize the make to stock and make to order business. Better lead time and less variability within the plant will reduce the end item buffer. 10 5 10 5 10 15 5 10 30 10 20 Customer All material and © copyright Demand Driven Institute 2013, all rights reserved Supplier Supplier Purchased Components Suppliers
- 8. Extending the Demand Driven Method • The extension of Demand Driven methods to shop floor scheduling and execution can be seen in the new book Demand Driven Performance – Using Smart Metrics • A series of articles in Strategic Finance Magazine previews the book – the articles are available for free download All material copyright 2013 Constraints Management Group, LLC
- 9. Introducing Control Points • Places to transfer, impose, and amplify control through a system. • The 14th edition of the APICS Dictionary defines control points as “Strategic locations in the logical product structure for a product or family that simplify the planning, scheduling, and control functions. Control points include gating operations, convergent points, divergent points, constraints, and shipping points. Detailed scheduling instructions are planned, implemented, and monitored at these locations.”(p. 33) All material copyright 2013 Constraints Management Group, LLC C
- 10. Placing Control Points Placed between decoupling points with the objective of better controlling the lead‐time zones between those points. A shorter and less variable lead time results in less stock required at the decoupling point (a working capital reduction). All material copyright 2013 Constraints Management Group, LLC C
- 11. Placing Control Points Placed between decoupling points and a customer when decoupling the end item is not possible or in a mixed mode operation. Customer C All material copyright 2013 Constraints Management Group, LLC Customer Customer Make/Configure to Order
- 12. Determining Control Points 1. Points of Scarce Capacity determine the total system output potential. The slowest resource‐‐the most loaded resource—limits or defines the system total capacity. 2. Exit and Entry Points are the boundaries of your effective control. Carefully controlling that entry and exit determines whether delays and gains are generated inside or outside your system. 3. Common Points are points where product structures or manufacturing routings either come together (converge) or deviate (diverge). One place controls many things. 4. Points that Have Notorious Process Instability are good candidates because being a control point provides focus and visibility to the resource and forces the organization to bring it under control or plan for, manage, and block the effect of its variability from being passed forward. All material copyright 2013 Constraints Management Group, LLC
- 13. Placing a Control Point In this case we have a resource is both the slowest pace resource as well a major integration point in the routings 10 5 10 5 10 15 All material copyright 2013 Constraints Management Group, LLC 5 10 C → 30 10 20 Customer Supplier Supplier Purchased Components Suppliers → → →
- 14. Scheduling a Control Point 10 5 10 5 10 15 All material copyright 2013 Constraints Management Group, LLC 5 10 30 10 20 Customer Supplier Supplier Purchased Components Suppliers → → → C Replenishment orders Sales Order Demand 1 2 3 4 5 6 7 8 9 10 11 12 Capacity The control point is finitely scheduled with both MTS and MTO orders Sales orders → Loading is important to see for lead time quotation
- 15. Synchronizing Material Release Schedule material release to the control point schedule Late release will jeopardize the control point schedule Early release raises WIP levels unnecessarily 10 5 10 5 10 15 All material copyright 2013 Constraints Management Group, LLC 5 10 30 10 20 Customer Supplier Supplier Purchased Components Suppliers → → → C → Work orders Work orders Work orders
- 16. Control Point Schedules We now have five schedules – all synchronized around a resource Control Point schedule (Drum) All material copyright 2013 Constraints Management Group, LLC 30 Customer Supplier Supplier Purchased Components Suppliers → → → C → DRUM
- 17. Protecting the Schedule We must insulate the schedules against the accumulated variability that occurs in the sequences preceding the schedule – delays are passed on, gains are not How can we make sure that the schedules are maintained (not rescheduled)? 10 5 10 5 10 15 All material copyright 2013 Constraints Management Group, LLC 5 10 30 10 20 Customer Supplier Supplier Purchased Components Suppliers → → → C → Note: the purchased part stock buffers protect the material release schedules against supplier variability
- 18. Time Buffers WO 1595 Upstream Processes All material copyright 2013 Constraints Management Group, LLC Scheduled Start at Control Point ▼ Scheduled Entry to Buffer ▼ WO 1781 WO 1626 WO 1601 WO 3279 WO 2001 C → Early Green BYUeFllFoEwR Red Late Example: 9 hour buffer
- 19. Buffers Inserted 10 5 10 5 10 15 All material copyright 2013 Constraints Management Group, LLC 5 10 30 10 20 Customer Supplier Supplier Purchased Components Suppliers → → → C →
- 20. The 10 Zone Buffer Board Early Green BYUeFllFoEwR Red Late All material copyright 2013 Constraints Management Group, LLC Scheduled Start at Control Point ▼ Scheduled Entry to Buffer ▼ Early Green BYUeFllFoEwR Red Late Example: 9 hour buffer Yet to be Received Received WO 1626 WO 1626 Green Yellow Red OK Investigate ACT
- 21. How a Buffer Board works Yet to Be Received Early 48709-01 Received Early Green Green Yellow All material copyright 2013 Constraints Management Group, LLC Yellow Red Red Late Late 9 Hours of Buffer Time scheduled on Drum (Wed 7:00 pm) 48801-01 Note: 16 hour work day Current Day and Time: Monday, 7:00 am
- 22. How a Buffer Board works Yet to Be Received Early 48709-01 Received Early Green Green Yellow All material copyright 2013 Constraints Management Group, LLC Yellow Red Red Late Late 9 Hours of Buffer Time scheduled on Drum (Wed 7:00 pm) 48801-01 Current Day and Time: Wednesday, 10:00 am Note: 16 hour work day
- 23. How a Buffer Board works Yet to Be Received Green 48709-01 Early Received Early Green Yellow All material copyright 2013 Constraints Management Group, LLC Yellow Red Red Late Late 9 Hours of Buffer Time scheduled on Drum (Wed 7:00 pm) 48801-01 Current Day and Time: Wednesday, 1:00 pm Note: 16 hour work day
- 24. How a Buffer Board works Yet to Be Received Received All material copyright 2013 Constraints Management Group, LLC Yellow Red 48709-01 Early Early Green Green Yellow Red Late Late 9 Hours of Buffer Time scheduled on Drum (Wed 7:00 pm) 48801-01 Current Day and Time: Wednesday, 4:00 pm Note: 16 hour work day
- 25. How a Buffer Board works Yet to Be Received Received Forced Reason Code All material copyright 2013 Constraints Management Group, LLC Yellow Red 48709-01 Early Early Green Green Yellow Red Late Late 9 Hours of Buffer Time scheduled on Drum (Wed 7:00 pm) 48801-01 Current Day and Time: Wednesday, 5:00 pm Note: 16 hour work day 49322-01 49527-03
- 26. How a Buffer Board works Yet to Be Received 49322-01 49527-03 Received All material copyright 2013 Constraints Management Group, LLC Yellow Red 48709-01 Early Early Green Green Yellow Red Late Late 9 Hours of Buffer Time scheduled on Drum (Wed 7:00 pm) 48801-01 Current Day and Time: Wednesday, 7:00 pm Note: 16 hour work day
- 27. Reason Code Analysis All material copyright 2013 Constraints Management Group, LLC
- 28. Analyzing Buffers Over Time Early Green BYUeFllFoEwR Red Late All material copyright 2013 Constraints Management Group, LLC