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Work study

5W

1H on work studyWhat is work-study?A productivity

improvement tool of Industrial Engg., a function

whose responsibility is to make

processes efficient

manufacturing easy

quality better

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It deals with various aspects of productivity

improvement like :

Workplace layout

Standards

Ergonomics etc

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Where is this done?At any place of workwhere value adding activity is carried out

When is work-study done?Q C D parametersare poor

Who does work-study? Trained work study

expert

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Why is this done?The objectives

1. Productivity improvement : Better utilization

of resources

2. Achievement of QCD objectives

3. To expose weak areas in management

4. To identify training needs

5. To establish industrial engineering standards

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6. Planning

7. Formulation of Incentive Schemes

How is this done?

Work study is made up of method study andwork measurement

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Method study

Method study deals with studying method ofdoing the work for identifying and eliminating non

value activities

Work that is carried out comprises of variousactivities which add only cost and no value

Method study removes the NVAs [non valueactivities] by design which makes the productivity

go up

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Work measurement

Work measurement leads toProductivity Improvement

Industrial Engineering standards

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20%

of

TotalTime

A

B

C

D

Basic Work Content of Product

and or Operation

Work Content added by defects

in design or specification of

product

Work Content added by

inefficient methods ofManufacture or Operation

Ineffective Time due to

shortcomings of Management

Ineffective Time within the

control of worker

1.Total

work

content

2.Total

ineffective

time

1+2 = Total Time of Operation

under existing conditions

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Basic work content

Only 20% of total time

Irreducible work content

Any reduction compromises quality

Determined by technology

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Work content added by management

A: Bad design of the product

Door handle on refrigerator

Bad specifications

Glass wool as insulator

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B: Inefficient process of manufacture

Using blunt tool for cutting

Excessive material handling

Using non standard inputs

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Ineffective time added by management

Bad working conditions

Muri in work, bad ergonomics, bad layout

Accidents due to lack of training

Lack of training

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Ineffective time added by workers

Rework of defects due to poor skill

Accidents due to

Carelessness

Lack of awareness

Fatigue

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Work measurementActivity sampling

Time study

PMTS

MOST

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Following are eight steps of work study in which

method study and work measurement activitiescomplement each other

1. Select [M/S & W/M]

Human angle Technological angle Economical angle Management needs

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3. Examine [M/S] - ask primary & secondary

questions4. Develop [M/S]Alternatives to current method

using principles of ergonomics &

motion economy

Use of human body

Arrangement of the work place Design of tools and equipment

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Compatibility between man & his work

environment

Reducing fatigue, mental & physical

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TIME STUDY

ACTIVITY

SAMPLING

ANALYTICAL

ESTIMATION

PREDETERMINED

TIME STANDARDS

[PMTS]

SYNTHESIS

5. Measure [W/M]

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6. Define [M/S & W/M]

Define the new method and time standards7. Install [M/S] Implementation of new method

8. Maintain [M/S]

Critical Phase as habits die hard Principals usedin developing new method are shown in the next

slide in dotted lines

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Work measurement

Time Study Activity Sampling [snap reading] Analytical Estimation

Predetermined Time Standards [PMTS] Synthesis

MOST [Maynard Operating SequenceTechnique]

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Concepts in Time Study

Element: An element is a distinctpart of a

specified job selected for convenience of

measurement and analysisWork cycle: A work cycle is a sequence of

elements which are required to perform a job or

yield a unit of production

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Qualified worker: Qualified worker is one who

has the necessary physical attributes, intelligence

and education, skills and knowledge to carryout the

work in hand to satisfactory standards of safety,quantity and quality

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Standard Performance: is the rate of output

qualified workers would naturally achieve

without over exertion as an average over the

working day or shift, provided they adhere tothe specified method and they are motivated to

apply themselves to work

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Rating: Relative assessment of a worker whose

performance is under observation by comparing

to the performance of a qualified worker

Standard Time: Time needed by a qualified

worker to completely perform a job under

normal working conditions

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Allowances: Additional time added to the

normal time to enable employees to

Attend to their personal needs (Relaxation

Allowance)Run more than one machine (Interference

Allowance)

Overcome unexpected and unavoidable delays

Increase their earnings (Policy Allowance)

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Observations: Observing the worker

performing an element of the job with his or her

full knowledge with the intention of recording the

time required for performance (when observations

are made as a part of time study)

Observed time: time recorded for performance

of an element by a worker under observation

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Basic time or Normalized time: The time

required by a qualified worker to perform the

element which is performed by the worker under

observation. When observed time is multiplied by

rating we get basic time or normalized time.

Suitability of Time Study

Time study is a statistical method

Time study is suitable for repetitive activities

which are found in a mass production system

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Deciding allowances

Compile standard time

Example ??

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Element

No

Observed

time in

mins.

Performa--

nce

Rating

Allowance

1 5 120% 15%

2 6 110% 15%

3 4 120% 15%

4 5.5 80% 15%

5 5 80% 15%

Calculate Standard Time & Standard Output

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Eleme-

nt No

Obser-

ved time

in mins

Perf.

Ratin-g

Norm-

alized

time in

mins

Allow-

ance

Stand-

ard time

in mins

1 4 130% ? 15% ?

2 ? 80% 4.8 15% ?

3 4.5 ? 5.4 15% ?

4 ? 120% ? 15% 8

Fill in the blanks

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Activity Sampling [snap reading]

Also known as work sampling or snap readingUsed for determining resource utilization

A set ofobservations of the phenomenon are

made to find the presence or absence of the

desired parameter

Observations are analyzed to determine resource

utilization

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It is a technique in which a large number of

instantaneous observations are made over a period

of time of a group of machines, processes or

workers. Each observation records what is

happening at that instant and the percentage of

observations recorded for a particular activity or

delay is a measure of the percentage of time

during which that activity or delay occurs

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How do we calculate number of observations?

E =K X p(1-p)/NE- tolerated inaccuracy of sample results (level of

inaccuracy), which is (1- confidence level indecimal)

p-extent of the phenomenon being observed

(idleness)

N-number of observations

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K=1, when S=68.27%, K=2, when S=95.45%

K=3, when S=99.73%In a work sampling study, a mechanic was found

to idle for 20% of the time. Find out the number of

observations needed to confirm the above figureswith a confidence level of 95% and a relative error

level by 5%

(Ref Ashwathappa for more numerical examples)

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Determining time standards by work sampling

Standard time for piece

= [(Total time in minuets X Working time

in %(from N observations) X performance index

in %)/(total number of pieces produced)] +

allowances

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Analytical Estimation

Work measurement is based on experience and

judgment

The job is split into bunch of elements and time

required is estimated applying ones experience

and judgment

Suitable for non repetitive activities carried out

infrequently like maintenance job or projects

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Analytical estimation is a work measurementtechnique whereby the time required to carry out

elements of a job at defined level of performance

is estimated from knowledge and practical

experience of performing the elements concerned

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Predetermined Time Standards [PMTS]

Standards are developed and fixed for all basic

human activities by ILO after extensive research

in this area

These standards are used to develop standard

time for a job after splitting the job into a series of

human activities

PMTS is applied when micro-motion study of

job is done

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When micro-motion study is done?

Predetermined Time Standards [PMTS] is awork measurement technique whereby time

estimated for basic human motions (classified

according to the nature of the motion and the

conditions under which it is made) are used to

build up the time for a job at a defined level of

performance

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Synthesis

Standards developed for other jobs are studied

From such jobs elements are located which are

common in the current job under study

Time standards of such elements are picked up

and used for developing time standard for current

job

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Synthesis is a work measurement technique for

building up the time for a job at a defined level of

performance by totaling element times obtained

previously from time studies on other jobscontaining the elements concerned, or from

synthetic data