1. Just-In-Time and Lean Systems
Chapter 7
Just-In-Time and Lean Systems

2. Just-In-Time (JIT)
Getting the right goods to the right place at the right time.
In an ideal JIT system, inventory = ??
JIT is a goal and a philosophy.

3. Lean System: A Broad View of JIT
Extending JIT philosophy to the entire organization, it is the Lean System.
In a lean system, everything is “right”, therefore no waste existing.

4. What are “Wastes”?
Waste is anything that doesn’t add value: time, money, resource, material, space, energy, labor activity, …
What may cause wastes?
Inventory
Unsynchronized production
Unstreamlined layouts
Unnecessary material handling
Scrap & rework …

5. Central Beliefs of Philosophy of JIT / Lean System
Elimination of waste
Broad view of operations
Simplicity
Continuous improvement
Visibility
Flexibility

6. Eliminate Waste
Anything in an operation that does not add value is waste.
Method A and method B can both get a task done. If A can do it better, or faster, or in a cheaper way, then there exist wastes in method B.

7. Everyone Has a Broad View of Organization
Instead of focusing on the assigned jobs only, a worker has a broad view of the organization: its mission and goals, and place his job in that big picture.

8. Simplicity
If a problem can be solved in a simple way, do not go complicate.

9. Continuous Improvement
Good enough is not good enough.
“Kaizen blitz” is a Japanese way of implementing continuous improvement idea. It is a few day’s intensive work of a cross-functional team aiming at resolving a bite-size chunk of a problem.

10. Visibility Visibility is to make waste visible.
Waste can only be eliminated after it’s discovered.
Clutter and inventory hide waste.
JIT requires clean facilities and open space so that no waste can be hidden.

11. Flexibility
Flexible so as to adapt to changes in the demand and environment.
Volume flexibility
Variety flexibility

12. Three Elements that Make JIT Work
Just-in-time manufacturing
Total quality management
Respect for people

13. JIT Manufacturing Kanbans & pull production systems
Quick setups & small lots
Uniform plant loading
Flexible resources
Efficient facility layouts

14. Pull Production
Process is driven by real demands (rather than demand forecasts).
Doing nothing unless a real demand calls (demand pull).
All work stations are “demand pull”.

15. Kanban Production System
A “pull production” system.
Real demand information is passed in relay backward from the last work station by using ‘kanbans (cards)’.
Each work station works according to the kanbans passed from the next station.
Each work station is responsible to pass proper kanbans to the previous station.

17. Illustration of Kanban in Textbook
© Wiley 2010

19. Number of Kanbans in a Withdraw Work Station
N = number of containers in a withdraw station
D = demand rate at the withdraw station
T = lead time from supply station
C = container size
S = safety stock to protect against uncertainty

20. Quick Setups & Small Lots
Setup times = time required to get the machine ready
cleaning, calibrating, changing tools, ...
Internal setups
The machine must stop when doing setup.
External setups
Setup can be performed when machine is running.

21. Uniform Plant Loading
“Leveling” of the production schedule so that the production of a product is evenly spread over the planning horizon in small batches.
Leveling the schedule can have big impact along whole supply chain.

22. An Example of Uniform Plant Loading
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23. Flexible Resources General purpose equipment: Multifunctional workers:
E.g.: drills, lathes, printer-fax-copiers, etc.
Capable of being setup to do many different things
Multifunctional workers:
Cross-trained to perform several different duties

24. Efficient Facility Layouts
Workstations in close physical proximity to reduce transport & movement
Streamlined flow of material
Often uses:
Cellular Manufacturing (instead of job shops)
U-shaped lines: (allows material handler to quickly drop off materials & pick up finished work)

25. Cellular Manufacturing (Group Technology)
Components are grouped according to their similarities.
Machines are grouped in cells so that a cell can complete the processing of some groups of components
Similar components are processed completely in a cell composed of dissimilar machines.

26. Job Shop Layout

27. Cellular Manufacturing (Group Technology)

28. TQM & JIT Quality at the Source Jidoka (authority to stop line)
Poka-yoke (foolproof the process)
Preventive maintenance

29. Respect for People: The Role of Workers
Cross-trained workers
Actively engaged in problem-solving
Workers are empowered
Everyone responsible for quality
Workers gather performance data
Team approaches used for problem-solving
Decision made bottom-up
Workers responsible for preventive maintenance

30. Respect for People: The Role of Management
Responsible for culture of mutual trust
Serve as coaches & facilitators
Support culture with appropriate incentive system
Responsible for developing workers
Provide multi-functional training
Facilitate teamwork

31. Supplier Relations & JIT
Use single-source suppliers
Build long-term relationships
Co-locate facilities to reduce transport
Stable delivery schedules
Share cost & other information

32. Benefits of JIT Smaller inventories Improved quality
Reduced space requirements
Shorter lead times
Lower production costs
Increased productivity
Increased machine utilization
Greater flexibility

33. Implementing JIT Manufacturing
Identify & fix problems
Reorganize workplace
Remove clutter & designate storage
Reduce setup times
Reduce lot sizes & lead times
Implement layout changes
Cellular manufacturing & close proximity
Switch to pull production
Extend methods to suppliers

34. Implementing JIT Is a Process of Continuous Improvement
© Wiley 2010

35. JIT in Services Multifunctional workers Reduce cycle times
Minimize setups
Parallel processing
Good housekeeping
Simple, highly-visible flow of work