Transcript PowerPoint Presentations 7

7.1
Chapter 7
Layout and flow
Pearson Education Ltd. Rob Judges
7.1
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.2
Layout and flow
Operations
strategy
Supply network design
Design
Layout
Layout
and flow
Flow
Process
technology
Improvement
Planning and
control
People, jobs
and
organization
Product/service
design
7.2
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.3
Key operations questions
In Chapter 7 – Layout and flow– Slack et al. identify the
following key questions:
• What is layout?
• What are the basic layout types used in operations?
• What type of layout should an operation choose?
• How should each basic layout type be designed in detail?
7.3
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.4
Layout involves the relative positioning of transformed
resources within operations and the allocation of tasks, which
together dictate the flow of transformed resources
The relative positioning
of transforming
resources
The allocation of tasks
to transforming
resources
The flow of
transformed resources
7.4
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.5
7.5
An innovative layout in a surgery improves its efficiency
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.6
Product flow in Cadbury’s
Flow of chocolate in
Cadbury’s factory
Flow of customers in
Cadbury World
Both Cadbury’s chocolate factory and its ‘Cadbury World’
visitor attraction use ‘product’ layout. But what will be different
about the layouts and why?
7.6
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.7
Functional layout in a library – the path of one customer
Loan books in subject order
On-line and CDROM access
room
Study desks
Enquiries
Company reports
To
journal
stack
Current
journals
Reference
section
Reserve
collection
Store
room
Entrance
7.7
Counter staff
Copying area
Exit
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.8
Department store with sports goods ‘shop-within-a-shop’
Books
and
videos
Footwear
Sports shop
Menswear
Perfume
and jewellery
Confectionery,
newspaper,
magazines
and stationery
Elevators
Women’s clothes
Luggage
and gifts
Entrance
7.8
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.9
An army induction centre which uses product layout
Waiting
area
Lecture theatre
Doctor
Waiting
area
Doctor
Blood
test
X-ray
Uniform
issuing area
Doctor
Doctor
Blood
test
Records:
personal
history and
medical
details
X-ray
Uniform
store
7.9
Doctor
Blood
Doctor test
X-ray
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.10
7.10
A product layout in a paper manufacturing operation
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.11
A restaurant complex with all four basic layout types
Cell layout buffet
Line
layout
cafeteria
Starter
buffet
Main course
buffet
Service line
Preparation
Functional layout kitchen
Oven
Dessert
buffet
Fixed-position layout
service restaurant
Cool room
Freezer
7.11
Vegetable prep
Grill
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.12
Advantages and disadvantages of fixed position layout
Fixed-position layout
Very high product and mix
flexibility
Advantages
Product/customer not moved
High variety of tasks for staff
Very high unit costs
Disadvantages
Scheduling space and activities
can be difficult
7.12
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.13
Advantages and disadvantages of functional layout
Functional layout
High product and mix flexibility
Advantages
Relatively robust in the case of
disruptions
Easy to supervise
Low utilization
Disadvantages Can have very high WIP
Complex flow
7.13
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.14
Advantages and disadvantages of cell layout
Cell layout
Can give good compromise
Advantages
Fast throughput
Group work can result in good
motivation
Disadvantages
Can be costly to rearrange
existing layout
Can need more plant
7.14
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.15
Advantages and disadvantages of product layout
Product layout
Low unit costs for high volume
Advantages
Opportunities for specialization
of equipment
Can have low mix flexibility
Disadvantages Not very robust in the case of
disruptions
Work can be very repetitive
7.15
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.16
Volume and variety characteristics of layout types
Flow is
intermittent
High
Variety
Low
Low
Volume
High
Functional
layout
Cell layout
Product layout
Regular flow more important
7.16
Regular flow more feasible
Fixed-position
layout
Flow becomes
continuous
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.17
The relationship between functional and layout types
Manufacturing
functional types
Project processes
Basic layout
types
Service
functional types
Fixed-position layout
Professional services
Jobbing processes
Functional layout
Service shops
Batch processes
Cell layout
Mass services
Mass processes
Product layout
Continuous processes
7.17
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
Basic layout types have different fixed and variable costs
that seem to determine which one to use
Fixedposition
Costs
7.18
Functional
Cell
Product
Use
Use fixed- functional
position
Use
cell
Use product
Volume
7.18
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
But uncertainty about exact fixed and variable costs
means the decision can rarely be made on cost alone
Costs
7.19
Fixed-position
Functional
Cell
Product
?
?
?
Use product
Volume
Use fixed-position
Use fixed-position or functional
Use functional
7.19
Use functional or cell or product
Use functional or cell
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.20
Detailed design techniques
Fixed position – resource location analysis
Functional layout – flow charts and relationship charts
Cell layout – product flow analysis
Product layout – assembly line balancing techniques.
7.20
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.21
Collecting information in functional layout
(a)
To
From
A
A
B
LOADS/DAY
B
C
D
17
-
30 10
A
20
B
13
C
7.21
(b)
LOADS/DAY
20
-
10
-
-
D
30
E
10 10 10 10
E
70
30
A
If direction is
not important,
collapses to
C
D
B
C
D
30
-
60 20
30
-
E
30
80
40
E
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.22
Collecting information in functional layout (Continued)
(b)
LOADS/DAY
A
A
B
C
D
B
C
D
30
-
60 20
30
-
E
(c)
LOADS/DAY
A
B
30
C
80
40
Or, alternatively
D
E
30
30
60
20
30
80
40
E
7.22
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.23
Collecting information in functional layout (Continued)
(a)
LOADS/DAY
To
From
A
A
B
7.23
UNIT COST/DISTANCE
TRAVELLED
To
B
C
D
E
2
2
2
2
3
3
4
2
2
C
D
17
-
30 10
A
20
B
3
C
2
D
10 10 10
E
2
20
-
10
-
-
D
30
E
10 10 10 10
E
A
B
13
C
(d)
70
30
From
If cost of flow
differs between
work centres,
combine with
2
2
2
10
2
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.24
Collecting information in functional layout (Continued)
(d)
To
From
A
A
7.24
(e) DAILY COST/DISTRANCE
TRAVELLED
UNIT COST/DISTANCE
TRAVELLED
To
B
C
D
E
2
2
2
2
A
3
3
4
B
2
2
B
3
C
2
D
10 10 10
E
2
2
2
2
From
To give
10
2
A
C
34
39
C
D 300
E
B
D
E
60 20
60
60
20
140
-
300
20 20 20 20
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.25
Collecting information in functional layout (Continued)
(e)
To
From
A
A
B
39
C
D
E
A
60 20
A
60
B
140 If direction is not
C
60
20
D 300
E
B
34
C
7.25
(f) DAILY COST/DISTRANCE
TRAVELLED
DAILY COST/DISTANCE
TRAVELLED
-
20 20 20 20
300
important,
collapses to
D
B
C
73
-
D
E
360 40
80
80
-
160
320
E
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.26
A relationship chart
CODE
A
E
I
O
U
X
DEPARTMENT
Metrology
E
Electronic testing
CLOSENESS
Absolutely necessary
Especially important
Important
Ordinary closeness
Unimportant
Undesirable
A
I
Analysis
O
X
U
I
Ultrasonic testing
U
O
I
Fatigue testing
X
U
U
O
E
Impact testing
7.26
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.27
Types of cell
Amount of indirect resources included in the cell
High
e.g. Plant-within-a-plant
manufacturing
operation
e.g. Specialist functional
manufacturing cell
Internal audit group
in a bank
Maternity unit
in a hospital
Low
e.g. Complete
component
manufacturing cell
e.g. Small multi-machine
manufacturing cell
Joint reference and
copying room in a
library
Proportion of
the resources
needed to
complete the
High transformation
included in the
cell
Lunch and snack
produce area in
supermarket
Low
7.27
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
Production flow analysis to allocate machines to cells
(a)
1
Component families
2 3 4 5 6 7
1
X
X
Machines
2 X
3
X
5 X
8
4 X
X
X
1
X
X
X
X
X
X
X
X
X
7
3
X
X
X
6
7.28
X
X
X
Component families
6 8 5 2 4 1
8
X
X
4
(a)
X
Machines
7.28
6 X
X
3
X
X
X
8
X
X
X
8
2
X
X
X
5
X
X
X
7
X
X
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.29
Balancing loss is that proportion of the time invested in
processing the product or service which is not used productively
An ideal ‘balance’ where work is allocated equally between the stages
3
Work allocated to stage
Cycle time = 2.5 mins
2.5
Load
2
1.5
1
0.5
0
7.29
1
2
Stage
3
4
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
Balancing loss is that proportion of the time invested in processing
the product or service which is not used productively (Continued)
7.30
But if work is not equally allocated, the cycle time will increase and
‘balancing losses’ will occur
3.5
Cycle time = 3.0 mins
Work allocated to stage
3
Idle time
2.5
Load
2
1.5
1
0.5
0
7.30
1
2
Stage
3
4
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.31
Element listing for Karlstad Cakes
Element
a
De-tin and trim
0.12 mins
Element
b
Reshape with off-cuts
0.30 mins
Element
c
Clad in almond fondant
0.36 mins
Element
d
Clad in white fondant
0.25 mins
Element
e
Decorate, red icing
0.17 mins
Element
f
Decorate, green icing
0.05 mins
Element
g
Decorate, blue icing
0.10 mins
Element
h
Affix transfers
0.08 mins
Element
i
Transfer to base and pack
0.25 mins
Total work content = 1.68 mins
7.31
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.32
Precedence diagram for Karlstad Cakes
0.17 mins
e
0.30 mins
a
0.12 mins
b
0.25 mins
c
0.36 mins
d
0.25 mins
0.05 mins
f
g
i
0.10 mins
h
0.08 mins
7.32
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.33
Allocation of elements and balancing for Karlstad Cakes
Stage 1
Stage 2
Stage 3
0.17 mins
Stage 4
e
0.25 mins
0.30 mins
a
b
0.12 mins
c
d
0.25 mins
0.05 mins
f
g
i
0.10 mins
0.36 mins
h
0.08 mins
0.6
0.5
Cycle time = 0.48 mins
Idle time
every cycle
0.4
0.3
= 0.24 mins
0.2
Proportion of
0.24
=
idle time per
4 × 0.48
cycle
= 12.5%
0.1
0
7.33
= (0.48 – 0.42) + (0.48 – 0.36) + (0.48 – 0.42)
1
2
3
4
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.34
‘Long and thin’ versus ‘short and fat’ layouts
A 60 minute task with a required cycle time of 15 minutes
15
15
15
1 every 15
minutes
15
60
30
30
30
30
1 every 15
minutes
60
1 every 15
minutes
60
60
7.34
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.35
Long and thin versus short and fat
• Long and short describes the number of stages
• Fat and thin describes the amount of work at each stage
Advantages of long-thin processes
controlled flow
higher mix flexibility
simple materials handling
higher volume flexibility
lower capital requirement
(no duplication)
greater robustness
greater efficiency
higher space utilization
7.35
Advantages of short-fat processes
less monotonous
higher ownership
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
7.36
Calculating the required cycle time
• Forecast Demands During the Period (A)
• Availability of Productive Time (B)
100
480 mins
• Cycle Time (C=B/A)
4.8 mins
• Deciding how many staff are needed
• Work Content of the Task (D)
• Cycle Time Required (C)
• Number of Staff (D/C)
7.36
55 mins
4.8 mins
11.46 (12)
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010