Leveling: Tortoise not Hare

1. Leveling: Tortoise not Hare

2. Ohno, 1988 The slower but consistent tortoise causes less waste and is much more desirable than the speedy hare that races ahead and then stops occasionally to doze. The Toyota Production System can be realized only when all the workers become tortoises.

3. The Leveling Paradox • The Leveling Paradox • Leveling provides a standardized core for Resource Planning • Why do this to yourself ? • Smoothing demand for upstream processes • How to Level • Initial efforts to level production and mix • Incremental leveling • Slice & Dice • Product families and subfamilies

4. Leveling: Core for Resource Planning

5. Example

6. Heijunka 1. Level, smooth production: product volume

7. Heijunka 2. Level, smooth production: product mix Traditional production Level production

8. Heijunka 3. Level, smooth production: product sequence

9. Leveling High Variety Product Mix • High volume parts --> built-to-stock signal --> supermarket --> replenished by Kanban • Low volume parts --> built to customer order

10. Why Leveling? • Problems: • Small batches --> • Frequent changeovers/change in material --> • Lost production --> • Missed schedule • Traditional solution: • Large batches  • Less changeovers/change in material

11. Why Leveling? • Toyota solution: • Lifting the “cloud” • Setup time reduction (SMED)  • Increased flexibility • Level material demand • Read Toyota Atsushi Niimi Interview

12. Cell Design • Tool for one-piece flow • Cell: • Group of workstations, machines or equipment • arranged such that a product can be processed progressively from one workstation to another • w/o waiting for a batch to be completed and • w/o additional handling between operations

13. Traditional Layout

14. Lean Cell Layout

15. U-shaped Cell Example

16. Designing Cells • Group similar products into families that can be processed on the same equipment in the same sequence • Calculate takt time • Determine the work elements and time required for making one piece • Determine equipment cycle time • Organize machines in order or processing (U-shaped) • Balance the cell • Determine how the work will be divided among operators

17. Manage Change Process • Operators • Crosstraining • Job rotation • Solve production problems • Improvement suggestions • Plan coordinate, and control their work • Group setting

18. Manage Change Process • Managers • Planning • Supervisors • Accounting • Reward system • Plan for demand changes

19. Advantages • Decreased • Transportation • Waiting time • WIP • Floorspace • Lead time • Increases flexibility (Variety and customization) • Better communication between operators --> improved quality and coordination

20. Value Stream Mapping

21. What is Value Stream Mapping • Value stream: Actions required to bring a product through the main flows essential to every product: • Production flow from raw material to customer delivery • Design flow from concept to launch • Information flow as important as material flow

22. Using the Mapping Tool

23. Current-State Map • Material Flow Icons • General Icons • Information Flow Icons

24. Material Flow Icons 1

25. Material Flow Icons 2

26. Information Flow Icons 1

27. Information Flow Icons 2

28. General Icons

29. Characteristics of a Lean Value Stream • Produce to your takt time • Takt time= rate of customer demand • Develop continuous flow wherever possible • Use supermarkets to control production where continuous flow does not extend upstream • Try to send the customer schedule to only one production process • Level the production mix • Level the production volume • Develop the ability to make “every part every day” (Level production sequence)

30. The Future-State Map • Goal: • Built a chain of production where the individual processes are linked to the customer and • Each process gets as close as possible to producing only what its customer needs when they need it • First pass: What can we do with what we have? • Later: Address product design, technology, and location issues

31. Key Question for Future-State Map • Will you build to a finished goods supermarket from which the customer pulls, or directly to shipping? • What is the takt time? • At what single point in the production chain will you schedule production • Where will you need to use supermarket pull systems in order to control production of upstream processes • How will you level the production mix • What increment of work will you consistently release • What process improvements will be necessary

32. Future-State Mapping Example • ACME Stamping • Stamped-steel steering brackets • Hold the steering column to the body of a car • Two versions: Left-hand side and right-hand-side

33. Achieving the Future-State Map • Plan for achieving future-state map • Future-state map • Any detailed process-level maps or layouts that are necessary • A yearly value-stream plan

34. Breaking Implementation into Steps • Divide into value-stream loops • The pacemaker loop • Flow of material and information between your customer and your pacemaker process • Most downstream loop • Impacts all the upstream processes in the value stream • Additional loops • Between pulls • Each pull-system supermarkets separate loop

35. The Value-Stream Plan • Shows: • Exactly what to do when, step-by-step • Measurable goals • Clear checkpoints with real deadlines and named reviewer(s)

36. Determine Starting Point • Look for loops where: • Process is well-understood by people • Likelihood of success is high • Big bang for the buck

37. Improvement Pattern • Develop a continuous flow that operates based on takt time • Establish a pull system to control production • Introduce leveling • Practice kaizen to continually • eliminate waste, • reduce batch sizes, • shrink inventory, and • extend the range of continuous flow

38. Conclusion • VSM cycle not one-time activity • Heart of day-to-day management • Serve the customer • Change in people

39. Homework • Develop Future State Map for TWI • Due: 03/02/09 Before class