1. Process Selection and Facility Layout

2. Learning Objectives
Explain the strategic importance of process selection.
Explain the influence that process selection has on an organization.
Describe the basic processing types.
Discuss automated approaches to processing.

3. Learning Objectives List some reasons for redesign of layouts.
Describe the basic layout types.
List the main advantages and disadvantages of product layouts and process layouts.
Solve simple line-balancing problems.

4. Introduction Process selection
Deciding on the way production of goods or services will be organized
Major implications
Capacity planning
Layout of facilities
Equipment
Design of work systems

5. Process Selection and System Design
Forecasting
Product and Service Design
Technological Change
Capacity Planning
Process Selection
Facilities and Equipment
Layout
Work Design

6. Process Strategy Key aspects of process strategy
Capital intensive (mix of equipment/labor)
Process flexibility
Design
Volume
Technology

7. Kinds of Technology
Operations management is primarily concerned with three kinds of technology:
Product and service technology
Process technology
Information technology
All three have a major impact on:
Costs
Productivity
Competitiveness

8. Technology Competitive Advantage
Innovations in
Products and services
Cell phones
PDAs
Wireless computing
Processing technology
Increasing productivity
Increasing quality
Lowering costs

9. Process Selection Variety How much Flexibility What degree Volume
Expected output
Batch
Job Shop
Repetitive
Continuous

10. Process Types Job shop Batch Repetitive/assembly line Continuous
Small scale
Batch
Moderate volume
Repetitive/assembly line
High volumes of standardized goods or services
Continuous
Very high volumes of non-discrete goods

11. Product and Service Processes
Process Type
Job Shop
Appliance repair Emergency room
Ineffective
Batch
Commercial baking Classroom Lecture
Repetitive
Automotive assembly Automatic carwash
Continuous (flow)
Steel Production Water purification
Low Volume
High Volume

12. Product – Process Matrix
Dimension
Job shop
Batch
Repetitive
Continuous
Job variety
Very High
Moderate
Low
Very low
Process flexibility
Unit cost
Volume of output
High
Other issues; scheduling
work-in-process inventory
labor skill

13. Process and Product Profiling
Process selection can involve substantial investment in
Equipment
Layout of facilities
Product profiling: Linking key product or service requirements to process capabilities
Key dimensions
Range of products or services
Expected order sizes
Pricing strategies
Expected schedule changes
Order winning requirements

14. Automation
Automation: Machinery that has sensing and control devices that enables it to operate
Fixed automation
Programmable automation

15. Automation Computer-aided design and manufacturing systems (CAD/CAM)
Numerically controlled (NC) machines
Robot
Manufacturing cell
Flexible manufacturing systems(FMS)
Computer-integrated manufacturing (CIM)

16. Facilities Layout
Layout: the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system
Product layouts
Process layouts
Fixed-Position layout
Combination layouts

17. Objective of Layout Design
Facilitate attainment of product quality
Use workers and space efficiently
Avoid bottlenecks
Minimize unnecessary material handling costs
Eliminate unnecessary movement of workers or materials
Minimize production time or customer service time
Design for safety

18. Importance of Layout Decisions
Requires substantial investments of money and effort
Involves long-term commitments
Has significant impact on cost and efficiency of short-term operations

19. The Need for Layout Design
Inefficient operations
For Example:
High Cost
Bottlenecks
Changes in the design
of products or services
The introduction of new products or services
Accidents
Safety hazards

20. The Need for Layout Design (Cont’d)
Changes in
environmental
or other legal
requirements
Changes in volume of
output or mix of
products
Changes in methods
and equipment
Morale problems

21. Basic Layout Types Product layouts Process layouts
Fixed-Position layout
Combination layouts

22. Basic Layout Types Product layout Process layout Fixed Position 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

23. Product Layout Used for Repetitive or Continuous Processing
Raw materials
or customer
Station 1
Station 2
Station 3
Station 4
Finished item
Material
and/or labor
Material
and/or labor
Material
and/or labor
Material
and/or labor

24. Advantages of Product Layout
High rate of output
Low unit cost
Labor specialization
Low material handling cost
High utilization of labor and equipment
Established routing and scheduling
Routine accounting, purchasing and inventory control

25. Disadvantages of Product Layout
Creates dull, repetitive jobs
Poorly skilled workers may not maintain equipment or quality of output
Fairly inflexible to changes in volume
Highly susceptible to shutdowns
Needs preventive maintenance
Individual incentive plans are impractical

26. A U-Shaped Production Line1 2 3 4 5 6 7 8 9 10 In
Out
Workers
Ease to cross-travel of workers and vehicles
More compact
More communication between workers

27. Used for Repetitive Processing or Continuous Processes
Product Layout
Product Layout
(sequential)
Work
Station 1
Station 2
Station 3
Used for Repetitive Processing
or Continuous Processes

28. Used for Intermittent processing Job Shop or Batch Processes
Process Layout
Process Layout
(functional)
Dept. A
Dept. B
Dept. D
Dept. C
Dept. F
Dept. E
Used for Intermittent processing
Job Shop or Batch Processes

29. Advantages of Process Layouts
Can handle a variety of processing requirements
Not particularly vulnerable to equipment failures
Equipment used is less costly
Possible to use individual incentive plans

30. Disadvantages of Process Layouts
In-process inventory costs can be high
Challenging routing and scheduling
Equipment utilization rates are low
Material handling slow and inefficient
Complexities often reduce span of supervision
Special attention for each product or customer
Accounting and purchasing are more involved

31. Fixed Position Layouts
Fixed Position Layout: Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed.
Nature of the product dictates this type of layout
Weight
Size
Bulk
Large construction projects

32. Cellular Layouts Cellular Production Group Technology
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

33. Functional vs. Cellular Layouts
Dimension
Functional
Cellular
Number of moves between departments
many
few
Travel distances
longer
shorter
Travel paths
variable
fixed
Job waiting times
greater
Throughput time
higher
lower
Amount of work in process
Supervision difficulty
Scheduling complexity
Equipment utilization

34. Service Layouts Warehouse and storage layouts Retail layouts
Office layouts

35. Design Product Layouts: Line Balancing
Line Balancing is the process of assigning
tasks to workstations in such a way that the workstations have approximately equal time requirements.

36. Cycle Time Cycle time is the maximum time
allowed at each workstation to
complete its set of tasks on a unit.

37. Determine Maximum Output

38. Determine the Minimum Number of Workstations Required

39. Precedence Diagram a b c d e
Precedence diagram: Tool used in line balancing to display elemental tasks and sequence requirements
A Simple Precedence
Diagram a b c d e
0.1 min.
0.7 min.
1.0 min.
0.5 min.
0.2 min.

40. Example 1: Assembly Line Balancing
Arrange tasks shown in Figure 6.10 into three workstations.
Use a cycle time of 1.0 minute
Assign tasks in order of the most number of followers

41. Example 1 Solution Workstation Time Remaining Eligible Assign Task
Revised Time Remaining
Station Idle Time 1
1.0
0.9
0.2
a, c c
none a - 2 b
0.0 3
0.5
0.3 d e

42. Calculate Percent Idle Time
Efficiency = 100 – Percent idle time

43. Line Balancing Rules Some Heuristic (intuitive) Rules:
Assign tasks in order of most following tasks.
Count the number of tasks that follow
Assign tasks in order of greatest positional weight.
Positional weight is the sum of each task’s time and the times of all following tasks.

44. Example 2 Plan to produce 400 units in 1 day (8 hours) c d a b e f g h
0.2
0.3
0.8
0.6
1.0
0.4
Immediate Task time
Task follower (min)
a b 0.2
b e 0.2
c d 0.8
d f 0.6
e f 0.3
f g 1.0
g h 0.4
h end 0.3

45. Solution to Example 2 a b e f d g h c Station 1 Station 2 Station 3

46. Bottleneck Workstation
1 min.
2 min.
30/hr.
Bottleneck

47. Parallel Workstations
1 min.
2 min.
60/hr.
30/hr.
Parallel Workstations

48. Copier Example Performance Task Must Follow Time Task Listed
Task (minutes) Below
A 10 —
B 11 A
C 5 B
D 4 B
E 12 A
F 3 C, D
G 7 F
H 11 E
I 3 G, H
Total time 66
This means that tasks B and E cannot be done until task A has been completed

49. Copier Example Performance Task Must Follow Time Task Listed
Task (minutes) Below
A 10 —
B 11 A
C 5 B
D 4 B
E 12 A
F 3 C, D
G 7 F
H 11 E
I 3 G, H
Total time 66 10 11 12 5 4 3 7 C D F A B E G I H
Figure 9.13

50. Production time available per day Minimum number of workstations
Copier Example
480 available mins per day
40 units required
Performance Task Must Follow
Time Task Listed
Task (minutes) Below
A 10 —
B 11 A
C 5 B
D 4 B
E 12 A
F 3 C, D
G 7 F
H 11 E
I 3 G, H
Total time 66
Cycle time =
Production time available per day
Units required per day
= 480 / 40
= 12 minutes per unit I G F C D H B E A 10 11 12 5 4 3 7
Figure 9.13
Minimum number of workstations =
∑ Time for task i
Cycle time n
i = 1
= 66 / 12
= 5.5 or 6 stations

51. Copier Example Line-Balancing Heuristics 1. Longest task time
Choose the available task with the longest task time
2. Most following tasks
Choose the available task with the largest number of following tasks
3. Ranked positional weight
Choose the available task for which the sum of following task times is the longest
4. Shortest task time
Choose the available task with the shortest task time
5. Least number of following tasks
Choose the available task with the least number of following tasks
480 available mins per day
40 units required
Cycle time = 12 mins
Minimum workstations
= 5.5 or 6
Performance Task Must Follow
Time Task Listed
Task (minutes) Below
A 10 —
B 11 A
C 5 B
D 4 B
E 12 A
F 3 C, D
G 7 F
H 11 E
I 3 G, H
Total time 66 I G F C D H B E A 10 11 12 5 4 3 7
Figure 9.13
Table 9.4

52. Copier Example 480 available mins per day 40 units required
Cycle time = 12 mins
Minimum workstations
= 5.5 or 6
Performance Task Must Follow
Time Task Listed
Task (minutes) Below
A 10 —
B 11 A
C 5 B
D 4 B
E 12 A
F 3 C, D
G 7 F
H 11 E
I 3 G, H
Total time 66 I G F H C D 10 11 12 5 4 3 7 B E A
Station 1
Station 2
Station 3
Station 5
Station 4
Station 6
Figure 9.14

53. (actual number of workstations) x (largest cycle time)
Copier Example
480 available mins per day
40 units required
Cycle time = 12 mins
Minimum workstations
= 5.5 or 6
Performance Task Must Follow
Time Task Listed
Task (minutes) Below
A 10 —
B 11 A
C 5 B
D 4 B
E 12 A
F 3 C, D
G 7 F
H 11 E
I 3 G, H
Total time 66
Efficiency =
∑ Task times
(actual number of workstations) x (largest cycle time)
= 66 minutes / (6 stations) x (12 minutes)
= 91.7%

54. Example 1 Balance by 1 Longest task time method 2 RPW method
Performance Task Must Follow
Time Task Listed
Task (minutes) Below
Balance by
1 Longest task time
method
2 RPW method ,2 ,4
,7,8 ,8
,10
Total time min.

55. Example 2 Balance by 1 Longest task time method 2 RPW method
Performance Task Must Follow
Time Task Listed
Task (minutes) Below
Balance by
1 Longest task time
method
2 RPW method ,5 ,5 ,8 ,9
Total time min.

56. Designing Process Layouts
Information Requirements:
List of departments
Projection of work flows
Distance between locations
Amount of money to be invested
List of special considerations
Location of key utilities

57. Example 3: Interdepartmental Work Flows for Assigned Departments1 3 2 30
170
100 A B C

58. Functional Layout Gear cutting Mill Drill Lathes Grind Heat treat
Assembly
111
333
222
444
1111
2222
3333
44444
333333
22222

59. Cellular Manufacturing Layout
1111
-1111
2222
- 2222
Assembly
3333
- 3333
4444
- 4444
Lathe
Mill
Drill
Heat
treat
Gear
cut
Grind

60. Linear Programming
Used to obtain optimal solutions to problems that involve restrictions or limitations, such as:
Materials
Budgets
Labor
Machine time

61. Linear Programming Model
Objective Function: mathematical statement of profit or cost for a given solution
Decision variables: amounts of either inputs or outputs
Feasible solution space: the set of all feasible combinations of decision variables as defined by the constraints
Constraints: limitations that restrict the available alternatives
Parameters: numerical values

62. Graphical Linear Programming
Graphical method for finding optimal solutions to two-variable problems
Set up objective function and constraints in mathematical format
Plot the constraints
Identify the feasible solution space
Plot the objective function
Determine the optimum solution

63. Linear Programming Example
Objective - profit
Maximize Z=60X1 + 50X2
Subject to
Assembly 4X1 + 10X2 <= 100 hours
Inspection 2X1 + 1X2 <= 22 hours
Storage 3X1 + 3X2 <= 39 cubic feet
X1, X2 >= 0

64. Linear Programming Example

65. Linear Programming Example

66. Linear Programming Example
Inspection
Storage
Assembly
Feasible solution space

67. Linear Programming Example
Z=900
Z=300
Z=600

68. Solution The intersection of inspection and storage
Solve two equations in two unknowns
2X1 + 1X2 = 22
3X1 + 3X2 = 39
X1 = 9
X2 = 4
Z = $740

69. Solutions and Corner Points
Feasible solution space is usually a polygon
Solution will be at one of the corner points
Enumeration approach: Substituting the coordinates of each corner point into the objective function to determine which corner point is optimal.

70. Simplex Method
Simplex: a linear-programming algorithm that can solve problems having more than two decision variables

71. MS Excel Worksheet for Microcomputer Problem

72. MS Excel Worksheet Solution