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10.1
Chapter 10
The nature of planning and
control
Pearson Education Ltd. Jules Selmes
10.1
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.2
Capacity planning and control
Operations
strategy
Design
Capacity planning
and control
Improvement
Planning and
control
The market requires…
products and services
delivered to requested
time, quantity and quality
The operation supplies...
delivered products and
services
10.2
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.3
Key operations questions
In Chapter 10 – The nature of planning and control – Slack et
al. identify the following key questions:
• What is planning and control?
• How do supply demand affect planning and control?
• What are the activities of planning and control?
10.3
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.4
Planning and control
• Planning is a formalization of what is intended to
happen at some time in the future.
• A plan does not guarantee that an event will actually
happen, it is a statement of intention.
• Although plans are based on expectations, during their
implementation things do not always happen as
expected.
• Control is the process of coping with any changes that
affect the plan. It may also mean that an ‘intervention’ will
need to be made in the operation to bring it back ‘on track’.
10.4
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.5
Planning and control (Continued)
Planning is deciding
what activities should take place in the
operation
when they should take place
what resources should be allocated to them
Control is
understanding what is actually happening in
the operation
deciding whether there is a significant deviation
from what should be happening
(if there is deviation) changing resources in order
to affect the operation’s activities.
10.5
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
Significance of planning and control
Long-term planning and control
Uses aggregated demand forecasts
Determines resources in aggregated form
PLANNING
Days/weeks/months
Time horizon
Months/years
10.6
Objectives set in largely financial terms
Medium-term planning and control
Uses partially disaggregated demand forecasts
Determines resources and contingencies
Objectives set in both financial and operations
terms
Hours/days
Short-term planning and control
10.6
CONTROL
Uses totally disaggregated forecasts or
actual demand
Makes interventions to resources to correct
deviations from plans
Ad hoc consideration of operations objectives.
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.7
Dependent and independent demand
Dependent demand
e.g. input tyre store in automobile plant
Demand for tyres is
governed by the number
of automobiles planned
to be made
10.7
For every automobile
that are planned to be
made, five tyres will be
needed
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.8
Dependent and independent demand (Continued)
Independent demand
e.g. tyre-fitting service
ACE
TYRES
Demand for tyres is governed by the
type of car arriving, the fluctuations in
the number of cars arriving and how
many tyres need replacing.
10.8
Demand for tyres is
largely governed by
random factors.
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.9
P : D ratios
Customer
orders
Obtain resources
Produce product/service
Deliver to customer
Produce to stock
D
P
Part produce to order
D
P
Produce to order
P
D
Resource to order
D
P
Allow time for
resourcing
10.9
Allow time
for creation
Allow time
for delivery
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.10
P : D ratios (Continued)
Resource to
order
Dependent
demand
Each product or
service (large)
compared with
total capacity of
the operation
Make to order
Make to stock
10.10
Independent
demand
Each product or
service (small)
compared with
total capacity of
the operation
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.11
The activities of planning and control
How much
to do?
When to
do things?
Scheduling
Sequencing
In what
order to do
things?
10.11
Loading
Monitoring
and control
Are activities
going to plan?
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.12
Loading – The reduction of time available for ‘valuable
operating time’
Maximum available time
Valuable operating
time
Quality
losses
10.12
Not worked
(planned)
Slow
Not worked
Set-up
and
running Equipment
(unplanned)
changeovers
‘Breakdown’
equipment
‘idling’
failure
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.13
Finite and infinite loading
Finite and infinite loading of jobs on three work centres A, B and C. Finite loading
limits the loading on each centre to their capacities, even if it means that jobs will be
late. Infinite loading allows the loading on each centre to exceed their capacities to
ensure that jobs will not be late.
Infinite loading
Finite loading
0
4
3
2
1
5
A
10.13
B
C
Work centre
A
B
C
Work centre
6
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.14
The hospital triage system
In Accident and Emergency departments, patients arrive at
random. Medical staff must rapidly devise a schedule.
Patients with serious illness need urgent attention. Less
urgent cases will have to wait. Routine non-urgent cases
will have the lowest priority of all.
10.14
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.15
10.15
Triage in the police
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.16
Gantt chart showing the schedule for jobs at each
process stage
Process
stage
Week
12
Initial spec Job A
Pre-coding
Job W
Final test
10.16
Week
14
Week
15
Job A
Job B
Job A
Job X
Job Y
Job Z
Job Y
Week
17
Week
16
Job C
Job B
Job X
Coding
Compact. check
Week
13
Week
18
Job D
Job D
Job C
Job B
Job C
Job B
Job A
Job X
Job E
Job A
Job B
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.17
Gantt chart showing the schedule for individual
jobs over time
JOB
Mon
5
Tue
6
Wed
7
Thur
8
Fri
9
Mon
12
Tue
13
Table
Shelves
Kitchen
units
Bed
10.17
V
Actual progress
Time now
V
Scheduled
activity time
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
Gantt chart by activity
JOB
Mon
5
Wood
preparation
T
Assembly
B
Wed
7
Thur
8
S
B
Paint
S
S
V Time
now
Mon
12
Tue
13
S
S
K
T
B
Fri
9
K
T
Finishing
Scheduled
activity time
10.18
Tue
6
V
10.18
K
T
Non-productive time
Actual progress
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.19
Pull and push philosophies of planning and control
Push control
CENTRAL OPERATIONS, PLANNING AND CONTROL SYSTEM
OR
Instruction on
what to make
and where to
send it
Work
centre
10.19
Work
centre
FORECAST
Work
centre
Work
centre
DEMAND
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.20
Pull and push philosophies of planning and control
(Continued)
Pull control
Work
centre
Work
centre
Delivery
10.20
Work
centre
Delivery
Request
Request
Request
Request
Work
centre
Delivery
DEMAND
Delivery
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.21
10.21
Pull and push philosophies of planning and control
(Continued)
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.22
Shift allocation
Shift allocation for the technical ‘hot line’
(a) on a daily basis (b) on a weekly basis
Mon
Number of staff
required
Peter
Walter
Marie
04:00
08:00
Jo
Claire
12:00
16:00
Shift pattern (24-hour clock)
(a)
10.22
Jo
Jo
Tue
3
5
Wed
5
Thu
Fri
Sat
Sun
5
3
2
2
Peter
X
X
X
X
O
O
X
Marie
X
X
X
X
X
O
O
Claire
X
X
X
X
O
O
X
Walter
O
X
X
X
X
X
O
Jo
O
X
X
X
O
X
X
20:00
X
Full day
O
Day off
(b)
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.23
A simple model of control
Input
Operation or
process
Intervention
Plans
Output
Monitor
Compare
/ replan
10.23
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010
10.24
The drum, buffer, rope, concept
Buffer of
inventory
Stage or
process
A
Stage or
process
B
Communication rope
controls prior activities
10.24
Stage or
process
C
Stage or
process
D
Stage or
process
E
Bottleneck
drum sets
the beat
Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 2010