1. 2.008 Manufacturing Systems
Spring 2004

2. Outline Manufacturing Systems Types of Plant Layouts Production Rates
Design and Operations
Spring 2004

3. Manufacture Market Research Conceptual Design Design for Manufacture
Unit Manufacturing Processes
Assembly and Joining
Factory, Systems & Enterprise
Spring 2004

4. What is mfg systems?
Spring 2004

5. Time spectrum of Typical Activities in a Manufacturing Organization
Seconds
Period
Activity
108
Decade
Plant design, Machine Selection,
107
Year
System Simulation
Process design: CAD
106
Month
Catalogs
Select manufacturing methods
Week
105
Day
Factory Operation
104
Ship-Receive
Hour
Transport Inventory
103
102
Minute
Part handling
101
Load/Unload
Assembly 1
Second .1
Machine control
CNC-DNC
.01
Adaptive control
Intelligent machines
.001
Millisecond
Process control
Spring 2004

6. How Man, Machine, and Material Spend Time in the Factory
People
Materials
Machines
Value-added
Waste
"Waste": waiting for materials,
watching machine running,
producing defects, looking for
tools, fixing machine
breakdowns, producing
unnecessary items, etc
“Waste”: transportation, storage, inspect on and rework
"Waste": unnecessary
movement of machine, setup
time, machine breakdown,
unproductive maintenance,
producing defective products,
producing products when not
needed, etc.
Spring 2004

7. Disruptions/Variation (Random Events)
Machine failure
Set-up change
Operator absence
Starvation/Blockage
Demand change
Spring 2004

8. Types of Plant Layout Job Shop Project Shop Flow Line Transfer Line
Cellular System
Spring 2004

9. Job Shop
Raw Material
Ready part A D C
Machines/Resources are grouped according to the process they perform
Spring 2004

10. Project Shop
Machines/Resources are brought to and removed from stationary part as required A C B D
Raw material/
Ready part
Spring 2004

11. Flow Line and Transfer Line
Raw Material
Ready part B C D F G
Machines/Resources are grouped in lines according to the processes sequence of part(s)
Spring 2004

12. Cellular System
Raw Material
Ready part B C E A D F G
Machines/Resources are grouped according to the processes required for part families
Spring 2004

13. Production Quantity and Plant Layout
Project Shop
Job Shop
Cellular System
Flow Line 1 10
100
1,000
10,000
100,000
Quantity
Spring 2004

14. Production Rates Case I: One machine Everything works M
Spring 2004

15. Production Rates (cont’d)
Case II:
One machine
Machine breaks down (disruption)
Everything else works M
Spring 2004

16. Production Rates (cont’d)
Case III:
Many machines
No machine breaks down
No buffers M1 M2 Mi Mk
Spring 2004

17. Production Rates (cont’d)
Case IV:
Many machines (same operation time)
No machine breaks down
No buffers M1 M2 Mi Mk
Spring 2004

18. Production Rates (cont’d)
Case V:
Many machines (same operation time)
Machine breaks down
No buffers M1 M2 Mi Mk
Spring 2004

19. Production Rates (cont’d)
Case VI:
Many machines and buffers in between
Machine breaks down M1 M2 Mi Mk B1 B2
Bk-1
Mk-1
Spring 2004

20. Production Rates (cont’d)
Production rate increases if:
Increase the rate of the slowest machine
Reduce the disruptions
Introduce “buffers”
Introduce in-process control
Spring 2004

21. Disruptions (Random Events)
Machine failure
Set-up change
Operator absence
Starvation/Blockage
Spring 2004

22. Waiting
Underutilization
Idleness
Inventory
Spring 2004

23. Inventory/Work-in-Process (WIP)
It costs money
It gets damaged
It becomes obsolete
It shrinks
It increases lead time
Spring 2004

24. Cycle Time and Lead Time
Order
Supply
Plant
Supplier
Customer
Spring 2004

25. Cycle Time “Cycle Time” ．The time a part spends in the system
Little’s Law: L = λw
L: average inventory
λ: average production rate
w: average cycle time
Spring 2004

26. Cycle Time (cont’d) Example: Operation time = 1, One-piece operation
Production rate = 1
Cycle time = 5
Inventory = 5 M1 M2 M3 M5 M4
Spring 2004

27. Cycle Time Batch Production1.
Operation time: 3 minutes
Batch (Lot) size: 1000
Cycle time = 1,000*3 + 1,000*3 + 1,000*3 = 9,000min
Op1
Op2
Op3
Spring 2004

28. Cycle Time One-Piece Production2.
Operation time = 3 minutes
Cycle time = 1,000*3 + 2*3 = 3,006 minutes
Op1
Op2
Op3
Spring 2004

29. Cycle Time and Lead Time
Order
Supply
Plant
Supplier
Customer
Spring 2004

30. Systems Design and Operation
Cycle time < Lead time
Lumpiness
Information contents
Spring 2004

31. Lumpy Demand Forging X Forging Y Steel Z Wrench A Wrench B Wrench C
Wrench D D 1 P 5 D 6 P 15 D 3 P 10 D 7 P 25
Forging X
Forging Y D 20 15 P 25 D 35 P 50
Steel Z D 75 25 50
Spring 2004

32. Typical Design Guidelines
Leveling
Balancing
Single-piece flow
Low materials handling
Low setup time
Smaller lot size
Low WIP
Faster feedback
Spring 2004

33. Plant Operations Push (MRP, ERP, etc.) vs. Pull (JIT)
Batch vs. One-piece
Spring 2004