Work Study.ppc.Class Lecture Butex
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Transcript of Work Study.ppc.Class Lecture Butex
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WORK STUDY
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WHATISWORKSTUDY?
Work study is the investigation of the work done in an
organization by means of a consistent system, in order to
attain the best possible use of men, machines and
materials at present available conditions.In another way work study may be defined asThe
systematic, objective, critical and imaginative examination
of all factors governing the operational efficiency of any
specified activity in order to effect improvement.
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PURPOSEOFWORKSTUDY
In general work study aims to
Lower cost.
Increased productivity.
Increased profitability.
Increased job-security.
Make work easier.
Establish fair tasks for every one.
Check achievements against standards.
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Everyone in the industry gets benefit from work study
Management gets benefit through increased efficiency and thus
increased profit.
Worker is assured of a fair return for a fair days work. He is
protected unfair demands. The work is made easier and more
productive.
Trade union gets a reliable data measuring fair days work andpayment through work study. This enables trade unions to do
more objective negotiations with the management based on
factual evidence.
Productivity through work enables greater amount of
production and services to optimum quality and lower prices. Sothe consumers are benefit.
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MEANSOFINCREASINGPRODUCTIVITY
There are six possible lines of attack onproductivity problems, which can be classifiedas follows:
1. Improve basic processes by research anddevelopment.
2. Improve existing and provide better plant andequipment.
3. Simplify the product, reduce and standardizethe range.
4. Improve existing methods of plant operation.
5. Improve the planning of work and the use ofman-power.
6. Increase the effectiveness of all employees.
Long term requireCapital.
Intermediate may require
capital
Short term
wil l require li t t le
or no capi tal
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WORKSTUDYASFIELDOFAPPLICATION
The following diagram shows how work study helps in increasing
productivityWork Study
Work measurementMethod Study
To improve the methodsof production To assess humaneffectiveness
To achieve improved factory and workplace layout improved design ofequipment. Better working environment
reduction of fatigue resulting in improveduse of materials, plant equipmentmanpower.
To achieve a basis for comparison ofalternative methods correct initialmanning. Continuous economy of
manpower; effective planning ofproduction; realistic labour costing;basis for sound incentive scheme.
Higher Productivity
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METHODSTUDY
The aims of method study are-
Better design of plant equipments and buildings. Improved layout of factory and offices.
Better working conditions and environment.
Higher standards of safety and health.
Improved flow of work.
Better quality. Greater job satisfaction.
Higher earnings.
Improved utilization of resources.
Effective material handling.
Efficient process and procedure. Optimum inventory.
Optimum output.
Improved administration.
Waste reduction.
Standardization and rationalization.
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STEPSINVOLVEDINMETHODSTUDY
Select job/process to be examined & observe
current performance high process cost, bottlenecks, tortuous
route, low productivity, erratic quality
Record & document facts
activities performed
operators involved - how etc
equipment and tools used
materials processed or moved
apply critical examination - challenge job
components & necessity (purpose, place,sequence, method).
develop alternative methods & present
proposals
document as base for new work system
Install, monitor (slippage) & maintain
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METHODSTUDYACTIVITIES
There are the following 5 method activities as described below:-
1. Operation:An operation is an action performed for advancingtowards desired result.
2. Inspection:An inspection occurs when the product is
removed for a time from production.
3. Storage:A Storage occurs when the product is removed for atime from production.
4. Delay: A delay occurs when some undesirable eventprevents/hinders the next planned activity e.g. waitingfor a machine to be repaired. A traffic jam.
5. Transport:A transport occurs when there is movement fromone place to another.
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METHODSTUDYSYMBOLS
In order to make a vivid presentation of facts, and to enable themind to understand them quickly and clearly, we use somesymbols instead of words, for the method study activities.
Operation
Inspection
Storage
Delay
Transport
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RECORDINGTECHNIQUE
For recording data the following aids may be
utilized
Graphs.
Tables.
Schematic models.
Flow chart.
Templates.
Histogram.
Frequency polygons and ogives.
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The process recording methods are
1. Operation/Outline process chart.
2. Flow process chart.
3. Two handed process chart and left hand right hand
process chart.
4. Activity chart.
5. Multiple activity charts.
6. Flow diagram.
7. String diagram.
8. Templates.9. Models and Materials.
10.Cycle Graph and Chronocycle graph.
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CRITICALEXAMINATIONQUESTIONS
Purpose
What, Why, What else might & Should
be done ? Place
Where, Why, Where else & Whereshould it be done ?
Sequence
When, Why then, When else could &
When should ? Person
Who, Why, Who else might & shoulddo it?
Means
How, Why, How else could, How else
should
a sound reason for everyactivity
no assumptions so doublecheck
quality, safety and healthmust not compromised
The objectives of critical examination of recorded facts of an existing orproposed method is to determine the true reasons underlying each event
and to make a systematic list of all possible improvements for later
development in a new and improved method.
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WORKMEASUREMENT
Work measurement is the application of techniquesdesigned to establish the time for a qualified workerto carry out specified jobs at a defined level ofperformance.
We have seen how total time to manufacture aproduct is increased by:
adding undesirable features to product,
bad operation of the processes, and
ineffective time added because of worker and
management.
All this leads to decreased productivity.
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INTRODUCTION
Work measurement (WM) is concerned withinvestigating, reducing and eliminating ineffectivetime, whatever may be the cause.
WM is the means of measuring the time taken in theperformance of an operation or series of operations insuch a way that the ineffective time is shown up andcan be separated out.
In practice, proving existence of the ineffective time isthe most difficult task.
After existence is proved, nature and extent is easy tosee!
WM is also used to set standard times to carry out thework, so that any ineffective time is not includedlater.
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PURPOSEOF WM
To reveal the nature and extent of ineffective
time, from whatever cause,
So that action can be taken to eliminate it; and
then,
To set standards of performance that are
attainable only if all avoidable ineffective time is
eliminated and work is performed by the best
method available.
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USESOF WM
To compare the efficiency of alternative methods.Other conditions being equal, the method whichtakes the least time will be the best method.
To balance the work of members of teams, in
association with the multiple activity charts, sothat, as far as possible, each member has taskstaking an equal time.
To determine, in association with man andmachine multiple activity charts, the number of
machines an worker can run.
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TIMESTUDY
A WM technique for
1. Recording the times and rates of working for
the elements of a specified job carried out
under specified conditions,
2. Analyzing the data so as to obtain the time
necessary for carrying out the job at a defined
level of performance.
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STEPSINMAKINGATIMESTUDY
Obtaining and recording all the information
about the job, the operator and the surrounding
conditions, which is likely to affect the carrying
out of the work.
Recording a complete description of the method,
breaking down the operation into elements.
Examining the detailed breakdown to ensure
that the most effective method and motions are
being used.
Measuring and recording the time taken by the
operator to perform each element of the
operation.
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STEPSINMAKINGATIMESTUDY
At the same time assessing the effective speed ofthe working of the operative in relation to theobservers concept of the rate corresponding to
standard rating. Extending the observed times to basic times.
Determining the allowances to be made over andabove the basic time for operation.
Determining the standard time for theoperation.
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BREAKINGTHEJOBINTOELEMENTS
An element is an distinct part of a specified job
selected for convenience of observation,
measurement and analysis.
A work cycle is the sequence of elements which
are required to perform a job or yield a unit of
production. The sequence may sometimes include
occasional elements.
For each job, a detailed breakdown of the
complete job into elements is necessary.Because.
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REASONSFORBREAKDOWNOFJOB
To ensure that productive work (or effective time) isseparated from unproductive activity (or ineffectivetime).
To permit the rate of working to be assessed more
accurately than would be possible if the assessmentwere made over a complete cycle.
To enable different types of elements to be identifiedand distinguished, so that each may be accorded thetreatment appropriate.
To enable elements involving high fatigue to beisolated and to make the allocation of fatigueallowances more accurate.
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REASONSFORBREAKDOWNOFJOB
To facilitate checking the method and so thatsubsequent omission or insertion of elementsmay be detected quickly.
To enable a detailed work specification to beprepared.
The enable time values for frequently recurringelements, such as the operation of machinecontrol or loading and unloading work-pieces
from fixtures, to be extracted and used incompilation of the synthetic data.
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TYPESOFELEMENTS
Arepetitive element is an element which occursin every work cycle of the job.
An occasional element does not occur in eachwork cycle of the job, but which may occur at
regular or irregular intervals. e.g. machinesetting.
For a constant element, the basic time remainsconstant whenever it is performed. e.g. switch themachine on.
Avariable element is an element for which thebasic time varies in relation to somecharacteristics of the product, equipment orprocess, e.g. dimensions, weight, quality etc.
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TYPESOFELEMENTS
Amanual element is an element performed by a
worker.
Amachine element is automatically performed by
a power-driven machine (or process).
Agoverning element occupies a longer time than
any of the other elements which are being
performed concurrently. e.g. boil kettle of water,
while setting out teapot and cups.
Aforeign element is observed during a study
which, after analysis, is not found to be necessary
part of the job.
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RECORDINGTIMEFORACTIVITIES
Cumulative timing
The watch runs continuously throughout thestudy.
At the end of each element the watch reading is
recorded. The individual element times are obtained by
subsequent subtractions.
The purpose of this procedure is to ensure that
all the time during which the job is observed isrecorded in the study.
Typically, most work-study persons attain fairdegree of accuracy quickly when using thecumulative method.
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RECORDINGTIMEFORACTIVITIES
Fly back time
The hands of the stopwatch is returned to zero atthe end of each element and are allowed to startimmediately, the time for each element beingobtained directly.
In a comparative study of two methods carriedout the Purdue University, the average error inreading the watch using the cumulative method
was +0.000097 min per reading and using theflyback method was -0.00082 min per reading.
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RECORDINGTIMEFORACTIVITIES
Cumulative time recording is preferred, because:
Trainees achieve reasonable accuracy more quickly.
It does not matter if element times are occasionallymissed by observed; the over-all time of the study will
not be affected. Foreign elements and interruptions are automatically
included since the watch is never stopped.
Temptation to adjust the element time to rating isless compared to flyback time.
Workers have greater faith in the fairness as they seethat no time can have been omitted.
Flyback method can have slight delays when thestopwatch is snapped back to zero at the end of eachelement.
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TIMESTUDY: RATING
Rating is the assessment of the workers rate of
workingrelative to the observers concept of the
rate corresponding to the standard pace.
It is a comparison of rate of working observed by
the work-study person with a picture of some
standard level.
The standard level is the average rate at which
qualified workers will naturally work at a job,
when using the correct method and whenmotivated to apply themselves to their work.
This rate of working is called standard rating.
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TIMESTUDY: RATING
The purpose of rating is to determine from the
time actually taken by the operator being
observed the standard time which can be
maintained by the average qualified worker and
which can be used as a realistic basis forplanning, and incentive schemes.
Time study is concerned with speed at which
operator carries out the work, in relation to the
concept of normal speed. Speed here means the effective speed of
operation.
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FACTORSAFFECTINGRATEOFWORKING
Factors outside the control of workers include:
Variation in the quality or other characteristics
of the material used, although they be within the
prescribed tolerance limit.
Changes in the operating efficiency of tools or
equipment within their normal life.
Minor and unavoidable changes in methods or
conditions of operations.
Variation in the mental attention for the
performance of elements.
Changes in the climatic and other conditions.
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FACTORSAFFECTINGRATEOFWORKING
Factors within workers control:
Acceptable variation in the quality of theprocess/product.
Variation due to workers ability.
Variation due to ability of mind, specificallyattitude.
Optimum pace at which the worker will work
depends on The physical effort demanded by the work.
The care required on the part of the worker.
Training and experience.
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RATINGFACTOR
The figure 100 represents standard performance.
If the operator is apparently performing with less
effective speed, than the assigned factor is less
than 100.
If, on the other hand, the effective rate of
working is above standard, the operator gets a
factor above hundred.
Essential idea being:
Observed time x Rating = Constant
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RATINGFACTOR
This constant is known as the basic time:
So, depending on the rating assigned for the
operator, the basic time can either be less than or
greater than the observed time.
TimeBasicRatingStandard
RatingtimeObserved x
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WORKCONTENT
The work content of a job or operation is definedas: basic time+ relaxation allowance+ anyallowance for additional work (e.g. the part ofrelaxation allowance that is work related).
Standard time is the total time in which a jobshould be completed at standard performancei.e. work content, contingency allowance fordelay, unoccupied time and interferenceallowance.
Allowance for unoccupied time and interferencemay not be frequently included in the standardtime calculations; however, the relaxationallowance is.
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STANDARDTIMECONSTITUENTS
Acontingency allowance is a small allowance of timewhich may be included in a standard time to meetlegitimate and expected items of work or delays,precise measurement of which is uneconomicalbecause of their infrequent or irregular occurrence.
Contingency allowance for work should includefatigue allowance; whereas the allowance for delayshould be dependent on the workers.
Typically contingency allowances are very small andare generally expressed as percentage of the total
repetitive minutes of the job.
Contingency allowance should not be more than 5%,and should only be given where the contingenciescannot be eliminated and are justified.
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STANDARDTIMECONSTITUENTS
Relaxation allowance is an addition to the basictime intended to provide the worker with theopportunity to recover from the physiological andpsychological effects of carrying out specified
work under specified conditions and to allowattention to personal needs.
The amount of the allowance will depend on thenature of the job.
One of the major additions to the basic time.
Industrial fatigue allowance, in turn, forms amajor portion of the relaxation allowance.
Relaxation allowances are also given aspercentages of the basic times.
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STANDARDTIMECONSTITUENTS
Typical values of relaxation allowance are 12-
20%.
In addition to including relaxation allowances,
short rest pauses could be added over the period
of work for an operator.
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OTHERALLOWANCES
Start-up / shut-down allowance
Cleaning allowance
Tooling allowance
Set-up / change-over allowance Reject / excess production allowance
Learning / training allowance
Policy allowance is an increment, other than the
bonus increment, applied to standard time toprovide a satisfactory level of earning for certain
level of performances under exceptional
conditions.
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STANDARDTIME
Now, we can add all the constituents to arrive atthe standard time for a job.
Standard time = observed time + rating factor +relaxation allowance + work related contingency
allowance + delay related contingency allowance.