chapter 10
TRANSCRIPT
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Chapter 9
Quick Review
Source: Bettman/Corbis
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
The elements of job design
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Some influences on job design and work organization
Job design
Team working
EmpowermentBehavioural approaches
Flexible working
Ergonomics
Division of labour
Scientific management
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Division of labourDividing the total task into smaller parts, each of which is
accomplished by a single person or team
Promotes faster learning
Makes automation easier
Ensures that non-productive work is reduced
Advantages
Leads to monotony
Can result in physical injury
Not particularly robust
Can reduce flexibility
Disadvantages
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Work study
Work study
Method study Work measurement
The systematic recording and critical examination of existing and proposed methods of doing work,
as a means of developing and applying easier and more effective
methods and reducing costs
The application of techniques designed to establish the time for a
qualified worker to carry out a specified job at a defined level of
performance
A generic term for those techniques, particularly method study and work measurement, which are used in the examination of human work in all its contexts, and which lead systematically to the investigation of all the factors which affect the efficiency and economy of the situations being
reviewed in order to effect improvement
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
A standard unit of work, e.g. 1 standard minute
The ‘standard’ unit of work
Light job90% work10% relaxation
Average job84% work16% relaxation
Heavy job68% work32% relaxation
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Ergonomics approach
How the person interfaces with the physical aspects of his or her workplace
How the person interfaces with the environmental conditions prevalent in his or her immediate working area
Ergonomics is concerned primarily with the physiological aspects of job design – that is, with
the human body and how it fits into its surroundings
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
More tasks which give increased
responsibility, autonomy or
decision-making Original
job tasks
Job enlargement
Job enrichment
More tasks of the same type
Behavioural approaches – Job enlargement and enrichment
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Empowerment means more than autonomy. It means giving staff the ability to change how they do their jobs and the authority to make changes to the job itself, as well as how it is performed.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Team working – where staff, often with overlapping skills, collectively perform a defined task and have a high degree of discretion
over how they actually perform the task
For example, a team of nurses sharing the responsibility to care for patients
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Flexible working – Increasingly, some people are expected to do their jobs while travelling, with only occasional visits to their ‘home’ location.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Division of labour
Ergonomics
Behavioural approaches
Empowerment
Team working
Flexible workingStaff treated
as a resource
Staff treated as a cost
Emphasis on managerial control
Emphasis on commitment and engagement of staff
Scientific management
Self-managed method study
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Chapter 10
The nature of planning and control
Source: Arup
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key teaching objectives
To make clear the separate but related nature of planning and control.
To distinguish planning and control from the design activities.
To emphasize the ubiquitous nature of the planning and control activity – all operations have to do it, but those in more turbulent environments find it more difficult than those in stable environments.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Operations strategy
Design Improvement
Planning and control
Operations management
Planning and control
The operation supplies ... delivered products and
services
The market requires … products and services delivered to requested
time, quantity and quality
Planning and control
Source: Arup
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
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’.
Planning and control
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Planning is deciding
Control is
what activities should take place in the operation
when they should take place
what resources should be allocated to them
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
Planning and control
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Significance of planning and controlT
ime
ho
rizo
n
Hou
rs/d
ays
Day
s/w
eeks
/mon
ths
Mon
ths/
year
s Long-term planning and controlUses aggregated demand forecasts
Determines resources in aggregated form
Objectives set in largely financial terms
Medium-term planning and controlUses partially disaggregated demand forecasts
Determines resources and contingencies
Objectives set in both financial and operations terms
Short-term planning and controlUses totally disaggregated forecasts or actual demand
Makes interventions to resources to correct deviations from plans
Ad hoc consideration of operations objectives
PLANNING
CONTROL
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Dependent and independent demand
Dependent demande.g. input tyre store in car plant
Demand for tyres is governed by the number of cars planned to be made
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Dependent and independent demand
Demand for tyres is largely governed by random factors
ACE TYRES
Independent demande.g. tyre fitting service
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
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
P:D ratios
Obtain resources Produce product / service Deliver to customer
DP
Produce to stock
DP
Part produce to order
DP
Produce to order
DP
Resource to order
Customer orders
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Dependent demand
Independent demand
Resource to order Each product or service is large compared with total capacity of the operation
Make to stock
Make to order
Each product or service is small compared with total capacity of the operation
P:D ratios
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Scheduling Loading
Sequencing Monitoring and control
When to do things?
In what order to do
things?
How much to do?
Are activities going to plan?
The activities of planning and control
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Quality losses Slow-
running equipment
Equipment ‘idling’ ‘Breakdown’
failure
Set-up and changeovers
Not worked (unplanned)
Valuable operating time
Maximum available time
Loading –The reduction of time available for ‘valuable’ operating time
Not worked (planned)
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Finite and infinite loading of jobs on three work centres A, B and CFinite 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
12
34
56
0
Work centre Work centreA B C A B C
Finite loading Infinite loading
Wee
ks
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
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.
The hospital triage system
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Process stage
Week 12
Week 13
Week 14
Week 15
Week 16
Week 17
Week 18
Job A Job B Job C Job D Job E
Job A Job BJob Y Job X
Job A Job BJob Z Job XJob Y
Job A Job BJob X Job C
Gantt chart showing the schedule for jobs at each process stage
Initial spec.
Pre-coding
Coding
Compact. check
Final test
Job A Job BJob W Job C Job D
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
JOB Mon 5
Tue6
Wed 7
Thur 8
Fri 9
Mon 12
Tue 13
Table
Shelves
Kitchen units
Bed
Scheduled activity time
Actual progressTime now
V
V
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
JOB Mon 5
Tue6
Wed 7
Thur 8
Fri 9
Mon 12
Tue 13
Wood preparation
Assembly
Finishing
Paint
Scheduled activity time
Actual progress
T
B
B T
S K
S S S
K
KTS
B T
Non-productive timeV
V
Time now
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Pull and push philosophies of planning and control
PUSH CONTROL
Work centre
Work centre
Work centre
Work centre
Instruction on what to make and where to
send it
DEMAND
FORECAST
OR
CENTRAL OPS. PLANNING AND CONTROL SYSTEM
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
PULL CONTROL
Work centre DEMAND
Pull and push philosophies of planning and control
Work centre
Work centre
Work centre
Request Request Request Request
Delivery Delivery Delivery Delivery
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Shift allocation for the technical ‘hotline’: (a) on a daily basis; (b) on a weekly basis
(a)Shift pattern (24-hour clock)
Peter
Jo
Walter Jo
Marie Claire Jo
04:00 08:00 12:00 16:00 20:00
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 X X O
Mon Tue Wed Thu Fri Sat Sun
Number of staff required
3 5 5 5 3 2 2
(b)
X OFull day Day off
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Operation or process
Input Output
Compare / re-plan
Intervention
Plans
A simple model of control
Monitor
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
The drum, buffer, rope, concept
Stage or process B
Stage or process A
Stage or process D
Stage or process E
Buffer of inventory
Stage or process C
Bottleneck drum sets the beat
Communication rope controls prior activities
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key Terms TestPlanningThe formalization of what is intended to happen at some
time in the future.
ControlThe process of monitoring operations activity and
coping with any deviations from the plan; usually involves elements of replanning.
Dependent demandDemand that is relatively predictable because it is
derived from some other known factor.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key Terms Test
Independent demandDemand that is not obviously or directly dependent on
the demand for another product or service.
Resource-to-orderOperations that buy-in resources and produce only
when they are demanded by specific customers.
Create-to-order or make-to-orderOperations that produce products only when they are
demanded by specific customers.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key Terms Test
Make-to-stockOperations that produce products prior to their being
demanded by specific customers.
P:D ratioA ratio that contrasts the total length of time customers
have to wait between asking for a product or service and receiving it (D) and the total throughput time to produce the product or service (P).
LoadingThe amount of work that is allocated to a work centre.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key Terms Test
Valuable operating timeThe amount of time at a piece of equipment or work centre
that is available for productive working after stoppages and inefficiencies have been accounted for.
Finite loadingAn approach to planning and control that allocates work to a
work centre only up to a set limit (usually its useful capacity).
Infinite loadingAn approach to planning and control that allocates work to
work centres irrespective of any capacity or other limits.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key Terms TestSequencingThe activity within planning and control that decides on the
order in which work is to be performed.
SchedulingA term used in planning and control to indicate the detailed
timetable of what work should be done, when it should be done, and where it should be done.
Forward schedulingLoading work onto work centres as soon as it is practical to
do so, as opposed to backward scheduling.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key terms Test
Backward schedulingStarting jobs at a time when they should be finished exactly
when they are due, as opposed to forward scheduling.
RosteringA term used in planning and control, usually to indicate staff
scheduling – the allocation of working times to individuals so as to adjust the capacity of an operation.
Push controlA term used in planning and control to indicate that work is
being sent forward to workstations as soon as it is finished on the previous workstation.
Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007
Key Terms TestPull controlA term used in planning and control to indicate that a workstation
requests work from the previous station only when it is required: one of the fundamental principles of just-in-time planning and control.
Drum, buffer, ropeAn approach to operations control, derived from the theory of
constraints (TOC), that uses the bottleneck stage in a process to control materials movement.
Theory of constraints (TOC)A philosophy of operations management that focuses attention on
capacity constraints or bottleneck parts of an operation; uses software known as optimized production technology (OPT).