1. LEAN system

2. Supporting goals
A balanced system, smooth, rapid flow of materials and/or work
Supporting goals:
Eliminate disruption
Make the system flexible
eliminate waste, especially exess inventory

3. Value That customer is willing to pay
That changes products color, function, shape, other attributes so that the product is getting closer to the customers requirements
That we do right at first time

4. Wastes
Those processes which directly do not create value for customers (muda, mura, muri) :
that are not necessary, and must be eliminated
That are necessary, because these are supporting value-add processes, cannot be eliminated (like transporting)
Muda – 7 wastes of lean
Mura – not leveled workflow
Muri – overloading of workers and assets

5. There are 7 wastes in LEAN (TIMWOOD):
Inventory
Overproduction
Waiting
Unnecessary transportation
Processing waste
Inefficient work methods
Defects

6. Lean thinking Operation Traditional improvement Lean improvement
Non value-add process
Value-add process

7. JIT Building Blocks Process design Product design
Personnel/organizational elements
Manufacturing planning and control

8. Process Design Small lot sizes Setup time reduction
Manufacturing cells
Limited work in process
Quality improvement
Production flexibility
Little inventory storage

9. Benefits of Small Lot Sizes
Reduces inventory
Less storage space
Less rework
Problems are more apparent
Increases product flexibility
Easier to balance operations
The ideal lot size is one piece. – it is not always realistic (machines process multiple items simultaneously, or with very long setup times)
Rework cost are less, ecause there are fewer items in a lot to inspect and rework.
Treditionally: long run of A product, then a long run of B product
While in the case of LEAN, small lots would frequantly shiftr from producing A to B and C. thes enables t respond more quickly to changing customer demand

10. Setup time
reducing changeover time ( because small lots require frequent setups)
SMED (single minute exchange of die)
External
Internal activities.
Song setup time require more inventory. Strong emphasis on educing setuo times.
Single –minute exchange of die (SMED). It needs catgorize changeover activities as either internal or external activiies. Internal activities can be done while machine is stopped. External activities do not invilve stopping the machine – it doens’t affect change over time
Convert as many activities as possible to external activities (In 1982 at Toyota SMED was reduced from 100 sec to 3 sec.)

11. Manufacturing cells
In Functional Manufacturing similar machines are placed close together (e.g. lathes, millers, drills etc)
In Cellular Manufacturing systems machines are grouped together according to the families of parts produced.
The major advantage is that material flow is significantly improved, which reduces the distance travelled by materials, inventory and cumulative lead times.

12. Quality improvement Kaizen – continuous improvement of the system
Jidoka (Autonomation) – automatic detection of defects during production. It consist two activities:
One for detecting defects when they occur
Another for stopping production to correct the cause of defects.
Poka Yoke safeguards built into the process to reduce the possibility of errors.

13. Work flexibility
Overall goal of lean is to achieve the ability to process mix of products in a smooth flow.
One potential obstacle is bottlenecks, which occur when portions of the system become overloaded. Because of
The absence of workers  cross trained workers
Not leveled workflow  use takt time
Example:
Total time per shift is 480 minutes per day
There are two shifts per day
There are two 20-minutes break and a 30 minutes lunch break per shift.
Daily demand is 80 pieces
Net time available per day= 2*(480-20*2-30)=820minutes
Takt time=820minutes/80 pieces=10,25 minutes
If the actual cycle time is higher, our customers won’t get their needs, if the actual cycle time is lower, there will be overproduction, and we have to inventory surplus products.

14. Inventory storage Inventory storage is a waste,
a buffer which can cover up problems, partly because inventory makes them seem less serious.

15. Product Design
Standard parts – fewer parts to deal with lower training costs
Modular design – easy to satisfy different needs
Highly capable production systems – quality is designed into the product and the production process
Concurrent engineering

16. Personnel/Organizational Elements
Workers as assets
Cross-trained workers
Continuous improvement
Cost accounting
Leadership/project management

17. Manufacturing Planning and Control
Level loading
Pull systems
Visual systems
Close vendor relationships
Reduced transaction processing
Preventive maintenance

18. Mixed model sequencing
the sequence (on the base of setup time and setup cost – let it be now A,C,B)
how many times the sequence should be repeated (determine the smallest integer)
how many units to produce
Model
Daily quantity
Units per cycle A 10
10/5=2 B 15
15/5=3 C 5
5/5=1

19. Pull/Push Systems
Pull system: System for moving work where a workstation pulls output from the preceding station as needed. (e.g. Kanban)
Push system: System for moving work where output is pushed to the next station as it is completed

20. Visual system
Kanban- a manual system responds to signals of the need for delivery of parts and materials (both to the factory and between the workstation)
Production kanban
Conveyance kanban

21. Traditional Supplier Network
Figure 12.4a
Buyer
Supplier

22. Tiered Supplier Network
Figure 12.4b
Supplier
Buyer
First Tier Supplier
Second Tier Supplier
Third Tier Supplier

23. Comparison of JIT and Traditional
Table 12.3
Factor
Traditional
JIT
Inventory
Much to offset forecast errors, late deliveries
Minimal necessary to operate
Deliveries
Few, large
Many, small
Lot sizes
Large
Small
Setup; runs
Few, long runs
Many, short runs
Vendors
Long-term relationships are unusual
Partners
Workers
Necessary to do the work
Assets

24. Preventive maintenance
Total Productive Maintenance – operators responsible for the equipments they use
Housekeeping – 5S
Sort
Straighten
Sweep
Standardize
Self-discipline

25. Thank you for your attention!