chapter 10

Slack, Chambers and Johnston, Operations Management 5th Edition © Nigel Slack, Stuart Chambers, and Robert Johnston 2007

Chapter 9

Quick Review

Source: Bettman/Corbis


The elements of job design


Some influences on job design and work organization

Job design

Team working

EmpowermentBehavioural approaches

Flexible working

Ergonomics

Division of labour

Scientific management


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


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


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


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


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


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.


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


Flexible working – Increasingly, some people are expected to do their jobs while travelling, with only occasional visits to their ‘home’ location.


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


Chapter 10

The nature of planning and control

Source: Arup


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.


Operations strategy

Design Improvement

Planning and control

Operations management


The operation supplies ... delivered products and

services

The market requires … products and services delivered to requested

time, quantity and quality


Source: Arup


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 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



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


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


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


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


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


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


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)


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


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



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


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


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


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


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


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


Operation or process

Input Output

Compare / re-plan

Intervention

Plans

A simple model of control

Monitor


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



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.


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.


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.


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.


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.


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.


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).

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chapter 10