1. Just-In-Time and Lean Production
Chapter 11
Just-In-Time and Lean Production
To Accompany Russell and Taylor, Operations Management, 4th Edition,  2003 Prentice-Hall, Inc. All rights reserved.

2. Web Links

3. What is JIT ? Producing only what is needed, when it is needed
A philosophy
An integrated management system
JIT’s mandate: Eliminate all waste

4. Basic Elements of JIT Flexible resources Cellular layouts
Pull production system
Kanban production control
Small-lot production
Quick setups
Uniform production levels
Quality at the source
Total productive maintenance
Supplier networks

5. Waste in Operations
Figure 11.1

6. Waste in Operations
Figure 11.1

7. Waste in Operations
Figure 11.1

8. Flexible Resources Multifunctional workers General purpose machines
Study operators & improve operations

9. Standard Operating Routine for a Worker
Sheet 1
Worker: Russell
Cycle Time: 2 min
Order of Operations time
Operations :10 :20 :30 :40 :50 1:00 1:10 1:20 1:30 1:40 1:50 2:00
Pick up material
Unload/
load machine 1
load machine 2
load machine 3
Inspect/
pack
Figure 11.2

10. Cellular Layouts
Group dissimilar machines in manufacturing cell to produce family of parts
Work flows in one direction through cell
Cycle time adjusted by changing worker paths

11. Manufacturing Cell with Worker Routes3
Cell 1
Figure 11.3

12. Worker Routes Lengthened as Volume Decreases
Cell 5
Worker 2
Cell 2
Worker 1
Cell 1
Worker 3
Cell 3
Cell 4
Figure 11.4

13. The Pull System Material is pulled through the system when needed
Reversal of traditional push system where material is pushed according to a schedule
Forces cooperation
Prevent over and underproduction

14. Kanban Production Control System
Kanban card indicates standard quantity of production
Derived from two-bin inventory system
Kanban maintains discipline of pull production
Production kanban authorizes production
Withdrawal kanban authorizes movement of goods

15. A Sample Kanban

16. The Origin of Kanban
a) Two-bin inventory system b) Kanban inventory system
Reorder
card
Bin 1
Bin 2
Q - R
Kanban R
Q = order quantity
R = reorder point - demand during lead time
Figure 11.5

17. Types of Kanbans
Figure 11.6

18. Types of Kanbans
Figure 11.6

19. Types of Kanbans
Figure 11.6

20. Types of Kanbans Kanban Square Signal Kanban Material Kanban
Marked area designed to hold items
Signal Kanban
Triangular kanban used to signal production at the previous workstation
Material Kanban
Used to order material in advance of a process
Supplier Kanbans
Rotate between the factory and suppliers

21. Determining Number of Kanbans
No. of Kanbans =
average demand during lead time + safety stock
container size
N =
dL + S C
where
N = number of kanbans or containers
d = average demand over some time period
L = lead time to replenish an order
S = safety stock
C = container size

22. Determining the Number of Kanbans
d = 150 bottles per hour
L = 30 minutes = 0.5 hours
S = 0.10(150 x 0.5) = 7.5
C = 25 bottles
N = =
= = 3.3 kanbans or containers
dL + S C
(150 x 0.5) + 7.5 25
Round up to 4 (to allow some slack) or down to 3 (to force improvement)
Example 11.1

23. Small-Lot Production Requires less space & capital investment
Moves processes closer together
Makes quality problems easier to detect
Makes processes more dependent on each other

24. Inventory Hides Problems

25. Lower Levels of Inventory Expose Problems

26. Components of Lead Time
Processing time
Reduce number of items or improve efficiency
Move time
Reduce distances, simplify movements, standardize routings
Waiting time
Better scheduling, sufficient capacity
Setup time
Generally the biggest bottleneck

27. SMED Principles Separate internal setup from external setup
Convert internal setup to external setup
Streamline all aspects of setup
Perform setup activities in parallel or eliminate them entirely

28. Common Techniques for Reducing Setup Time
Figure 11.8

29. Common Techniques for Reducing Setup Time
Figure 11.8

30. Common Techniques for Reducing Setup Time
Figure 11.8

31. Uniform Production Results from smoothing production requirements
Kanban systems can handle +/- 10% demand changes
Smooths demand across planning horizon
Mixed-model assembly steadies component production

32. Mixed-Model Sequencing
Example 11.2

33. Quality at the Source Jidoka is authority to stop production line
Andon lights signal quality problems
Undercapacity scheduling allows for planning, problem solving & maintenance
Visual control makes problems visible
Poka-yoke prevents defects

34. Visual Control
Figure 11.9

35. Visual Control
Figure 11.9

36. Visual Control
Figure 11.9

37. Kaizen Continuous improvement Requires total employment involvement
Essence of JIT is willingness of workers to
Spot quality problems
Halt production when necessary
Generate ideas for improvement
Analyze problems
Perform different functions

38. Total Productive Maintenance (TPM)
Breakdown maintenance
Repairs to make failed machine operational
Preventive maintenance
System of periodic inspection & maintenance to keep machines operating
TPM combines preventive maintenance & total quality concepts

39. TPM Requires Management to:
Design products that can be easily produced on existing machines
Design machines for easier operation, changeover, maintenance
Train & retrain workers to operate machines
Purchase machines that maximize productive potential
Design preventive maintenance plan spanning life of machine

40. Supplier Policies Locate near to the customer
Use small, side loaded trucks and ship mixed loads
Consider establishing small warehouses near to the customer or consolidating warehouses with other suppliers
Use standardized containers and make deliveries according to a precise delivery schedule
Become a certified supplier and accept payment at regular intervals rather than upon delivery

41. Benefits of JIT Reduced inventory Improved quality Lower costs
Reduced space requirements
Shorter lead time
Increased productivity
Greater flexibility
Better relations with suppliers
Simplified scheduling and control activities
Increased capacity
Better use of human resources
More product variety

42. JIT Implementation Use JIT to finely tune an operating system
Somewhat different in USA than Japan
JIT is still evolving
JIT isn’t for everyone

43. JIT In Services Competition on speed & quality
Multifunctional department store workers
Work cells at fast-food restaurants
Just-in-time publishing for textbooks
Construction firms receiving material just as needed