WORK STUDY

Eng. K.C Wickramasinghe

BSc(Hon’s), AMIESL

Dept. of Mechanical & Manufacturing

Engineering,

Faculty of Engineering,

University of Ruhuna.

Lecture Session 01

01

ME 8323 Production and Operations

Management

Work Study is the systematic examination of the methods of carrying

on activities so as to improve the effective use of resources and to set up

standards of performance for the activities being carried out

Systematic Examination: Examining the activity critically to

simplify, to modify the method of operation to reduce unnecessary or

excess work, or the wasteful resources

To Improve the Effective Use of Resources: Develop the method of

operation to make use of all resources in improve the productivity

To Set up Standards of Performance: setting up a

time standard for performing that activity

What is work study?

02 Main aim: to reduce time involve in elements

Definition

03

British Standard 3138: 1969 for Workstudy:

„Work study is a generic term for those techniques particularly

Method Study and Work Measurement, which are used in the

examination of human work in all its context, and which leads

to the systematic investigation, if all the resources and factors

which affects the efficiency and economy of the situation being

reviewed, in order to effect improvement”.

Workstudy: two independent techniques

Method Study (MS)

Work Measurement (WM)

04

Work Study

Method Study

(to improve method

of operation)

Work Measurement

(to assess human

effectiveness)

Resulting in more

effective use of

material, plant & equipment

and manpower

Making possible improved

planning and control and

as a basis for sound

Incentive scheme

Higher productivity

05

Work Study Techniques

Method Study: the systematic recording & critical examination of existing and

proposed ways of doing work as a means of developing and applying easier and

more effective methods, and thus reducing costs

Work Measurement: the application of techniques designed to establish the time

for a qualified worker to carry out a specified job at a specified level of

performance

MS & WM - closely linked (Theory: MS first, them WM)

MS for reduction of the work content of a job/ operation

WM for the investigation of any ineffective time associated with it; and subsequent

establishment of time standards for the operation developed by MS

Method Study

06

Purpose/Objective:

To find better ways of doing things to improve efficiency

To remove unnecessary work, avoidable delays, and other form of waste

MS may be requested by departmental or senior management due to:

The introduction of new products, services or equipment

The identification of problems:

Bottlenecks, causing unbalanced workflow

Idle workers or equipment – i.e. under use of resources

Poor morale indicated by trivial complaints or absenteeism

Excessive errors due to rejected work

Etc.

MS Procedure

07

SELECT

the job to be studied

RECORD

by collecting past data or

by direct observation

EXAMINE

by challenging purpose,

place, sequence and

method of work

DEVELOP

new method, drawing on

contribution of those

concerened

DEFINE

new method and present it

EVALUATE

results of different

alternative solutions

MAINTAIN

and establish control

procedures

INSTALL

new method and train

persons in applying it

Step 1: Select the Work

Three factors to be considered in selection process

– Economic, Technical and Human factors

– Significant savings is the first

– Pareto Analysis

08

20 different products generates different

level of profits

09

03 items account for

60% profit

They would be

priority of study

07 items contribute

25% of the profit

They are assumed as

second importance

Other products give

lower profit

The study may not

take place for them

Step 2: Record the existing Work Method &

All Others

10

Success depends on the accuracy of records

Two phases in Recording:

• Rough sketch or charting of the job to establish important

details

• More formal and accurate charts or diagrams for clear and

precise details

Std. Techniques and tools for recording

Std. charts and diagrams

Common Charts & Diagrams

11

Type Base Name

Chart Indicate

Process

Sequence

Outline process chart

Flow process chart

- workflow process chart

- material process chart

- equipment process chart

Two handed process chart

Procedure flowchart

Chart Use Time-

Scale

Multiple activity chart

Simo chart

Diagram Indicate

Movement

Flow diagram

String diagram

Cycle graph

Chrono-cycle graph

Travel chart

Process Charts Symbols

12

Symbol Name Description

OPERATION Indicates main steps in a process, method or

procedure

INSPECTION Indicates an inspection for quality and/or check

for quantity

TRANSPORT Indicates the movement of workers, material or

equipment from place to place

DELAY (Temporary

Storage)

Indicates a delay in the sequence of events: e.g.

waiting between consecutive operations

STORE (Permanent

Storage)

Indicates a controlled storage in which material

is received into or issued from s store

DECESION (not

much used)

Indicates the decision point for other operation

13

Process Charts Symbols

Process Charts Symbols

14

Process Charts Symbols

Flow Process Chart

String Diagrams

Use for activities in which workers move at irregular intervals between a number of points in the working area

Very common situation in industry

Examples:

– An operator is looking after more than one machine

– Labourers are delivering materials to or removing work from a series of machines or workplaces

– In stores and shops, where a variety of materials are being removed from or put away into racks and bins

– In restaurant and canteen, staff move to different location during the preparation and service of meals

String Diagrams

A to D, A to H, D to

L travelled more

Need critical

examination

Attempt to put the

stations closer

Multiple Activity Chart

Typing a letter

Able to see

individual

operations in a

specific time

Able to visualize

areas (idle time) to

be improved

(reduced)

Idle

Types the Letter

Goes to

Manager's Office

Goes back to

Office

Type the Letter

Separate Copies

Goes to

Manager's Office

Types the

EnvelopIdle

Idle

Type Envelop,

Insert Letter &

Place it Inside

Check & Sign

Letter Dictated

Idle

Idle

Idle

Typewriter ManagerTypist

05

20

15

10

25

Step 3: Examine the records

Examine the records for accuracy

Examine the records for development

If no recorded/sufficient details, improve records or choose a

different/better method

“transportation” and “delay” - generally give greatest scope for

improvement

Possible to eliminate certain operations, which will automatically

affect transportation and delays

Critical examination by two questions

Primary Questions and secondary questions

Primary questions

Purpose: What is actually achieved?, Why is the activity necessary at all?

Place: Where is it being done?, Why is it done at that particular place?

Sequence: When is it done?, Why is it dome at that particular time?

Person: Who does it?, Why is it done by that particular person?

Means: How is it done?, Why is it done at that particular way?

Secondary Questions

Purpose: What else could be done? What should be done?

Place: Where else could it be? Where should it be done?

Sequence: When else could it be? When should it be done?

Person: Who else could it be? Who should do it?

Means: How else could it be? How should it be done?

Step 4: Develop (develop improved method)

From critical examination:

– Shortcomings of the present operation

– Possibilities of a new improved method

Once a new method is accomplished:

– Record on charts

– Compare with the original method

Most important: complete elimination of unnecessary

activities

Changes to materials, product design, process design, tools or

the work place may facilitate for elimination or combination

If elimination is not possible, make attempt to combine

If all fails, try to simplify by reducing operations, delays,

transport

Simplification: to permit the worker to complete the job

more quickly and easily

Flow Diagram(Rec. Dept. of Aircraft Factory:

Existing Method)

Flow Diagram (Rec. Dept. of Aircraft

Factory: Proposed Method)

Step 5: Evaluate Alternative Method

Proposed Alternative for Development

Some for immediate introduction

Some need further actions before implementation (New

Eqip)

Detailed cost-benefit analysis for the selected option

Project report, recommended action for final review

Include implementation plan, if completely new method

Step 6: Define the Improved Method

Written standard practice, - “improved instruction sheet”

This Serves the following several purpose:

– Records for future reference

– Explain the new method to magt, supervisors, & operatives

– Advises all concerned of any new equipment & layout

– Aid to training operatives

– Forms the basis for time studies (i.e. work mesure‟t)

Step 7: Install the Improved Method

Most difficult part

Needs corporation from all levels

Personal qualities of the work study person is a gift

Stages in Installation:

– Gaining acceptance for management, supervisors and

workers

– Preparing to make the changes

– Controlling the change over

Step 8: Maintaining the New Method

Maintaining the new method:

– To make sure liability of getting benefits

Potential Issues to be Faced:

– New method - Liable to change from time to time during the operation

– Some assumptions in the improved method may be realized no longer valid

Reviewed at regular intervals to make allowances for any changes

Reason for Changes:

– Deliberate alterations to method for good reason

– Changes as a result of suggestions schemes

– Minor innovations introduced by supervisors and workers during the operations

Methods and Movements at the Work Place

Major area work-study for enhancing the productivity of man

and machines

So far, Major focus was on separate activities involved with

workers, machines and materials

Now the focus is on one worker working at a workplace,

bench or table

Focus on movement of hands, fingers and body

Major areas: assembly works in repetitive nature

Methods and Movements at the Work Place

Usually working area depends on the anthropometric data of

human body

Consider Normal working area of workbench for average

worker

– Ex: stretching forwards to pick material involves the use of

the back muscles, thereby causing fatigue

– Objective is reduce fatigue and improve productivity

– This is addressed by “principles of motion economy”

Anthropometric data of Human Body

Maximum Working Area

Principles of Motion Economy

Principles concerning the economy of manual movements

– Developed as a result of long term experience

Objective is to improve method at the workplace

03 Major Groups to improve productivity:

• Use of human body

• Arrangement of the work place

• Design of tools and equipment

Useful not only in shops, but also in offices

Principle can not always be applied

But, they form a basis for improving the efficiency and

reducing fatigue of manual work

Use of Human Body Two Hands Movement:

– Begin & complete movements at the same time

– Not idle at the same time except during the rest

Arm motion: should be made in opposite and symmetrical directions and should be made simultaneously.

Hand & body motion: maintain at lowest level

Classification of Hand-motions

– Finger motion – more fatiguing

– Wrist motions

– Forearm motions – most desirable for light & repetitive work

– Upper arm motions

– Shoulder motions (This class of motions results in disturbance of the

posture)

Use of Human Body

Employ momentum as advantage, maintain at minimum

In the tasks where the momentum must be overcome by the

worker's muscles, momentum must be reduced to a

minimum by decreasing the weight of the tools and parts

because it causes fatigue.

Maintain continuous curved movement - Avoid straight line

motions involving sudden and sharp changes

Use of Human Body

Use the Rhythm for smooth & automatic performance

Rhythm can refer to the regular repetition of a certain cycle of

motions by an individual. Rhythm which is a proper sequence of

motions, assists in making the operation practically an automatic

performance - there is no mental effort on the part of the operator.

Eye fixations should be as few and as close together as possible.

◦ Confine eye movements to a comfortable area

◦ Do not change the eye focus frequently

◦ Eg: containers been placed directly in front of the operator, the head

movements would have been eliminated entirely and her eye

movements would have been greatly reduced.

Arrangement of the Workplace

Definite & fixed stations for all tools & materials

Pre-position tools & materials to reduce searching

Gravity feed to deliver materials to closer point

Tools, materials - within maximum working area

Arrange materials & tools to permit the best sequence of motions

Use ejectors to remove finished parts wherever possible (avoid workers effort)

Provision for adequate lighting – intensity, proper colour, direction

Chair to permit good posture

Height of workplace and seat: allow alternate setting

Colour of workplace: to reduce fatigue and make contrast

Design of Tools & Equipment

Jig, fixture or foot-operated devices for hand “holding”

Combine two or more tools to reduce tool handling time

Where each finger performs some specific movement, such as in

typewriting, the load should be distributed in accordance with the inherent

capacities of the fingers.

Contact of Handles (cranks and large screwdrivers) should be designed that

as much of the hand as possible can come into contact with the handle.

(useful in large forces)

Least changes to body position to obtain higher efficiency of levers,

crossbars and hand wheels

Obtain mechanical advantages wherever possible

Layout Simplification

If similar work by each hand, a separate supply of materials/parts for each

hand

If eyes used for part/material selection, no head turn for selection

Use semi-circular in preference to circular arrangement (Refer the Figure)

Use ergonomics principles for workplace design (Refer the Figure)

Nature and shape of material for bin design (Figure)

Hand tools picked up with the body rhythm, least disturbance and without

special journey

Automatic tool return (Refer the Figure)

Drop finished work with least hand and eye movement in first time (Refer

the Figure)

Ergonomics (or human factors) is the scientific discipline concerned with the

understanding of interactions among humans and other elements of a system,

and the profession that applies theory, principles, data and methods to design

in order to optimize human well-being and overall system performance.

Which arrangement is more effective?

Think about application area?

Posture for Sitting Position

Motion-Economy Devices

Workstation Layout

Heavy duty assembly bench

Introduction to work study. 4th revised edition By George Kanawaty, International Labor Office