1. Facility Layout
Technical Note 6

2. Facility Layout Defined
Facility layout can be defined as the process by which the placement of departments, workgroups within departments, workstations, machines, and stock-holding points within a facility are determined.
This process requires the following inputs:
Specification of objectives of the system in terms of output and flexibility.
Estimation of product or service demand on the system.
Processing requirements in terms of number of operations and amount of flow between departments and work centers.
Space requirements for the elements in the layout.
Space availability within the facility itself. 3

4. Basic Production Layout Formats
Process Layout
Product Layout
Group Technology (Cellular) Layout
Fixed-Position Layout 4

5. Basic Production Layouts
Product Layout
Layout that uses standardized processing operations to achieve smooth, rapid, high volume flow.
Process Layout
Layout that can handle varied processing requirements.
Fixed-Position Layout
Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed. 4

6. Basic Production Layouts
Cellular Manufacturing (Layout)
Layout in which machines are grouped into a cell that can process items that have similar processing requirements
Group Technology
The grouping into part families of items with similar design or manufacturing characteristics

7. Layout Structures
Job shop
Batch
Assembly line
Continuous flow

8. Process Layout (Job Shop)
Product 3
Product 2
Product 1 A B C
Product 1
Product 2 D E F
Product 3

9. Process Layout –
Position of equipment is dominant consideration

11. Process-Focused Strategy
Facilities are organized by process
Similar processes are together
Example: All drill presses are together
Low volume, high variety products
‘Jumbled’ flow
Other names
Intermittent process
Job shop 11

12. Process Layout: Interdepartmental Flow
Given
The flow (number of moves) to and from all departments
The cost of moving from one department to another
The existing or planned physical layout of the plant
Determine
The “best” locations for each department, where best means interdepartmental transportation, or flow, costs 6

13. Process Layout: CRAFT Approach [COMPUTERIZED RELATIVE ALLOCATION OF FACILITIES TECHNIQUE]
Omit Slide
It is a heuristic program; it uses a simple rule of thumb in making evaluations:
"Compare two departments at a time and exchange them if it reduces the total cost of the layout."
It does not guarantee an optimal solution.
CRAFT assumes the existence of variable path material handling equipment such as forklift trucks. 8

14. Process Layout: Systematic Layout Planning
Numerical flow of items between departments
Can be impractical to obtain
Does not account for the qualitative factors that may be crucial to the placement decision
Systematic Layout Planning
Accounts for the importance of having each department located next to every other department
Is also guided by trial and error
Switching departments then checking the results of the “closeness” score
Omit Slide 9

15. Example of Systematic Layout Planning: Reasons for Closeness
Omit Slide
Code 1 2 3 4 5 6
Reason
Type of customer
Ease of supervision
Common personnel
Contact necessary
Share same price
Psychology 10

16. Example of Systematic Layout Planning:Importance of Closeness
Omit Slide
Value
Closeness
Line
code
Numerical
weights A
Absolutely necessary 16 E
Especially important 8 I
Important 4 O
Ordinary closeness OK 2 U
Unimportant X
Undesirable
-80 11

17. Example of Systematic Layout Planning: Relating Reasons and Importance
Omit Slide
From To
Area
(sq. ft.) 2 3 4 5
1. Credit department 6 I -- U 4 E
100
2. Toy department U I A
400 -- 1
1,6
3. Wine department U X
300 -- 1
4. Camera department X
100 1
5. Candy department
100
Letter
Closeness rating
Number
Reason for rating 12

18. Example of Systematic Layout Planning:Initial Relationship Diagram
Omit Slide 1 E 3 I 4 U U 2 5 A 13

19. Example of Systematic Layout Planning: Initial and Final Layouts
Omit Slide 2 5 1 4 3
50 ft
20 ft
Final Layout
Adjusted by square
footage and building
size 1 2 4 3 5
Initial Layout
Ignoring space and
building constraints 14

20. Process Focused Strategy - Pros & Cons
Advantages
greater process flexibility
more general purpose equipment
lower initial capital investment
Disadvantages
more “specialist” trained personnel required
more difficult production planning and control 13

21. Product Layout (Flow Shop)B C
Product 2
Product 2 D E F
Product 3
Product 3 D E F

22. Product Layout –
Flow of product is dominant
consideration

24. Product-Focused Strategy
Facilities are organized by product
High volume, low variety products
Where found
Discrete unit manufacturing
Continuous process manufacturing
Other names
Line flow production (flow shop)
Continuous production 17

25. Product-Focused Strategy Pros & Cons
Advantages
lower labor skills
easier production planning and control
higher equipment utilization
Disadvantages
lower product flexibility
more specialized equipment
usually higher capital investment 18

26. Group Technology: Transition from Process Layout
1. Grouping parts into families that follow a common sequence of steps.
2. Identifying dominant flow patterns of parts families as a basis for location or relocation of processes.
3. Physically grouping machines and processes into cells. 35

27. Batch/Lot Thinking Departmental (Batch Process) Specialization Saw Saw
Grinder
Grinder
Corrected
Heat Treat
Lathe
Lathe
Lathe
Press
Press
Press 8

28. Single-Piece Flow Thinking
Group Technology Cells
Grinder 1 2
Lathe
Press
Saw
Lathe
Heat Treat
Grinder A B
Lathe
Press
Saw
Lathe 9

29. Group Technology
Assembly Line Cells

30. Benefits of Group Technology
Changeover setup time reduced for tooling and equipment
Automation may be possible
Operator may be specially trained with improved expertise
Quality of output improved
In-process inventory reduced
Productivity improved
Lead time reduced
Improved human relations

32. Fixed Position Layout
Question: What are our primary considerations for a fixed position layout?
Answer: Arranging materials and equipment concentrically around the production point in their order of use. 36

33. Volume and Variety of Products
Low Volume High
Repetitive
High Volume
Variety of
Variety Process
Process
Low Variety
Products
(Intermittent)
(Modular)
Process
(Continuous)
One or very few
Projects
Poor Strategy
(Fixed costs and cost changing to other products are high)
units per lot
Very small runs, high
Job Shops
Aluminum part
variety
Modest runs, modest
Disconnected
variety
Cell Assembly
Repetitive
Long runs, modest
Poor Strategy
(High variable costs)
Connected
variations
Repetitive
Motor Assembly
Very long runs,
Continuous
Changes in
Part Molding
attributes 24

34. Assembly Lines Balancing Concepts
Question: Suppose you load work into the three work stations below such that each will take the corresponding number of minutes as shown. What is the cycle time of this line?
Station 1
Minutes per Unit 6
Station 2 7
Station 3 3
Answer: The cycle time of the line is always determined by the work station taking the longest time. In this problem, the cycle time of the line is 7 minutes. There is also going to be idle time at the other two work stations. 15

35. Main Points of Line Balancing
An analysis of production lines
Nearly equally divides work between workstations while meeting required output
Has objectives to
Maximize efficiency
Minimize number of work stations 51

36. Example of Line Balancing
You’ve just been assigned the job a setting up an electric fan assembly line with the following tasks: 16

37. Example of Line Balancing: Structuring the Precedence Diagram
Task Predecessors
Task Predecessors
A None
E D
B A
F E
C None
G B
D A, C
H F, G A B G H C D E F 17

38. Example of Line Balancing: Precedence Diagram
Question: Which process step defines the maximum rate of production? A C B D E F G H 2
3.25 1
1.2 .5
1.4
Answer: Task C is the cycle time of the line and therefore, the maximum rate of production. 17

39. Example of Line Balancing: The Bottleneck
Total Minutes 18

40. Example of Line Balancing: Determine Cycle Time
Question: Suppose we want to assemble
100 fans per day. What would our cycle
time have to be?
Answer:
Question: What else can the 4.2 min time be called other than cycle time? 19

41. Example of Line Balancing: Determine Theoretical Minimum Number of Workstations
Question: What is the theoretical minimum number of workstations for this problem?
Answer: 19

42. Example of Line Balancing: Rules To Follow for Loading Workstations
Primary: Assign tasks in order of the largest number of following tasks.
Secondary (tie-breaking): Assign tasks in order of the longest operating time 21

43. Station 1 Station 2 Station 3 Task Followers Time (Mins) 6 4 3 0.5 A CB D E F G H 2
3.25 1
1.2 .5
1.4
Station 1
Station 2
Station 3
Task
Followers
Time (Mins) 6 4 3
0.5 23

44. Station 1 Station 2 Station 3 A (4.2-2=2.2) Task Followers Time (Mins)C B D E F G H 2
3.25 1
1.2 .5
1.4
Station 1
Station 2
Station 3
A (4.2-2=2.2)
Task
Followers
Time (Mins) 6 4 3
0.5 24

45. A (4.2-2=2.2) B (2.2-1=1.2) Station 1 Station 2 Station 3 TaskC B D E F G H 2
3.25 1
1.2 .5
1.4
A (4.2-2=2.2)
B (2.2-1=1.2)
Task
Followers
Time (Mins) 6 4 3
0.5
Station 1
Station 2
Station 3 25

46. A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2) Idle= .2 Station 1 Station 2C B D E F G H 2
3.25 1
1.2 .5
1.4
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Task
Followers
Time (Mins) 6 4 3
0.5
Station 1
Station 2
Station 3 26

47. C (4.2-3.25)=.95 A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2) Idle= .2F G H 2
3.25 1
1.2 .5
1.4
C ( )=.95
Task
Followers
Time (Mins) 6 4 3
0.5
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Station 1
Station 2
Station 3 27

48. C (4.2-3.25)=.95 Idle = .95 A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2)F G H 2
3.25 1
1.2 .5
1.4
Task
Followers
Time (Mins) 6 4 3
0.5
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Station 1
Station 2
Station 3 28

49. D (4.2-1.2)=3 A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2) Idle= .2C B D E F G H 2
3.25 1
1.2 .5
1.4
D ( )=3
Task
Followers
Time (Mins) 6 4 3
0.5
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Station 1
Station 2
Station 3
C ( )=.95
Idle = .95 29

50. C (4.2-3.25)=.95 Idle = .95 D (4.2-1.2)=3 E (3-.5)=2.5 A (4.2-2=2.2)B D E F G H 2
3.25 1
1.2 .5
1.4
C ( )=.95
Idle = .95
D ( )=3
E (3-.5)=2.5
Task
Followers
Time (Mins) 6 4 3
0.5
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Station 1
Station 2
Station 3 30

51. C (4.2-3.25)=.95 Idle = .95 D (4.2-1.2)=3 E (3-.5)=2.5 F (2.5-1)=1.5A C B D E F G H 2
3.25 1
1.2 .5
1.4
C ( )=.95
Idle = .95
D ( )=3
E (3-.5)=2.5
F (2.5-1)=1.5
Task
Followers
Time (Mins) 6 4 3
0.5
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Station 1
Station 2
Station 3 31

52. C (4.2-3.25)=.95 Idle = .95 D (4.2-1.2)=3 E (3-.5)=2.5 F (2.5-1)=1.5A C B D E F G H 2
3.25 1
1.2 .5
1.4
C ( )=.95
Idle = .95
D ( )=3
E (3-.5)=2.5
F (2.5-1)=1.5
H ( )=.1
Idle = .1
Task
Followers
Time (Mins) 6 4 3
0.5
A (4.2-2=2.2)
B (2.2-1=1.2)
G (1.2-1= .2)
Idle= .2
Station 1
Station 2
Station 3
Which station is the bottleneck? What is the effective cycle time? 32

53. Example of Line Balancing: Determine the Efficiency of the Assembly Line33

54. Assembly Line Balancing The General Procedure
Determine cycle time by taking the demand (or production rate) per day and dividing it into the productive time available per day
Calculate the theoretical minimum number of work stations by dividing total task time by cycle time
Perform the line balance and assign specific assembly tasks to each work station 50

55. Assembly Line Balancing Steps
1. Determine tasks (operations)
2. Determine sequence
3. Draw precedence diagram
4. Estimate task times
5. Calculate cycle time
6. Calculate number of work stations
7. Assign tasks (load workstations)
8. Calculate efficiency 52

56. Mixed-Model Processing
Short cycle-interval (time)
Production of a variety of types, sizes, or models of a product family on the same line or within the same cell.

57. Example – The Fresh Bakery: Cakes
Daily sales for: Product L (Lemon Pound)
12 Product M (Chocolate Mud)
3 Product N (Nine Layer Carrot)
What is the best schedule for these products?
What are we assuming for this schedule to work?

58. Example Daily sales for: 24 Product L 12 Product M 3 Product N
Step 1 - find minimum ratio
8 L M – 1 N
Step 2- determine number of cycles
39/13 = 3

59. Example
In order to meet daily demand, this cycle will have to repeat 3 times
Step 3 - find the mix of the units that is most repetitive.
LLM LLM N LLM LLM
What are we assuming for this schedule to work?
Demand is uniform and our objective is
to avoid inventory.

60. Summary - Comparison Process Focus Product Focus Bank
1. Product: Small
1. Product: Large
quantity, large
quantities, small
variety
variety
2. Equipment:
2. Equipment:
General purpose
Special-purpose
3. Operators broadly
3. Operators less
skilled
broadly skilled
4. Many job
4. Few work orders
instructions
and job instructions;
standardization 20

61. Process/Product Continuum
Process Focused
(intermittent process)
Product Focused (continuous process)
Group Technology
Continuum
High variety, low volume
Low utilization
General-purpose equipment
Low variety, high volume
High utilization
Specialized equipment 23