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Work Study & WorkMeasurement
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WORK STUDY
Objectives of work & method study :
1.To analyze the present method of doing the job inorder to develop a new and better method.
2.To measure the work content of the job by measuring
the time required to do the job by a qualified worker
and hence to establish a standard time.
3.To increase the productivity by ensuring the best
possible use of human, machine and materials
resources and to achieve best quality product at
minimum possible cost.
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Work study
4.To reduce excessive material handling or movement
and thereby reduce the fatigue to workmen.
5.To improve utilization of resources
6.To eliminate wasteful and inefficient motions
7.To standardize work methods or processes, working
conditions, machinery, equipment and tools.
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WORK STUDY
BENEFITS OF WORK & METHOD STUDY
1.Work simplification
2.Improved working method3.Improved workplace layout
4.Improved equipment design
5.Better working condition
6.Better material handling
7.Improved work flow
8.Less fatigue to workmen
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WORK STUDYBENEFITS OF WORK & METHOD STUDY
9.Optimum utilization of resources
10.Higher safety to workmen
11.Shorter production cycle time
12.Higher job satisfaction for workmen
13.Reduced wastages
14.Reduced manufacturing cost and higher productivity
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Work Measurement
Work Measurement helps to determine how
long it should take to do a job
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Standard Time
Standard Time - The length of time a qualified worker
takes to complete a specific job, using appropriate
processes and tools and allowing time for personal
fatigue, and unavoidable delays
Standard time is used in:
Costing the labor component of products
Tracking employee performance
Scheduling & planning required resources
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Normal Time
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Other Time Factors Used in
Calculating Standard Time
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Computation of Standard Time
OT PRF PA RA CA SA POA
NT
ST
AT
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Computation of Standard Time
OT=Observed time
PRF=Performance rating factor
PA=Process allowance
RA=Relaxation allowance
CA=Contingency allowance
SA=Special allowance
POA=Policy allowanceST=Standard time
AT=Allowed time
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Computation of Standard Time
Normal Time = Observed Time x Rating Factor
= Observed Time x (Observed Rating Standard Rating)
Relaxation allowance Allowance given to overcome the fatigue
due to physical exertion, working condition, and personal needs such
as for drinking water, for going to wash room, for attending telephone
calls etc.
Contingency allowance This allowance is given for infrequent
activities such as obtaining special materials from store, sharpening of
tools, getting a special tool from store etc.
Process allowance Allowance given to the worker to
compensate him forenforced idleness due to nature of a process or
operation such as working on Automatic Machine during which worker
is forced to be idle.
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Computation of Standard Time
Special allowance :
(i) Inference allowance is given to a worker when he/she is looking
after2 / 3 machines. One machine may be idle when the workerworks on another machine for a short period and allowance has to be
given to the worker for this loss of production.
(ii)Periodic activity allowance - for activities carried out periodically
during a work cycle e.g. setting up a tool on the machine.
Standard Time = Normal Time + All relevant allowances
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Setting Standard Times
Step 1: Choose the specific job to be studied
Step 2: Tell the worker whose job you will be studying
Step 3: Break the job into easily recognizable units
Step 4:Estimate the sample size based on level of accuracy and
confidence level
Step 5: Time each element, record data & rate the workers
performance
Step 6: Compute the normal time
Step 7: Compute the standard time
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Doing a Time Study Need to determine how many observations are required
Involves determining the level of accuracy required and confidence
level desired
n : number of observations of an element that are needed
Z : the number of normal standard deviations needed for desired
confidence
S : the standard deviation of the sample
a : desired accuracy or precision
x-bar : the mean of the sample observations
2
x
s
a
z
n
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Pats Pizza Place: Pat hires an analyst to determine a standard time to preparea large pepperoni and cheese pizza. He takes 10 observations of the 7elements and calculates the mean time and the standard deviation perelement. He must then calculate the # of observations to be within 5% of the
true mean 95% of the time.
The analyst must calculate the observations for each element to determine how
many additional observations must be taken. The maximum number of 25 (in this
case) for element #7 means that an additional 15 observations must be made and
then the observed times are revised.
nsobservatio25
0.24
0.03
0.05
1.96
x
s
a
zn
22
7
1
2
3
4
5
6
7
8
9
10
A B C D E
Example 11.3 Pat's Pizza Place
Standard Deviation Mean Observed Revised Observed
Work Element (minutes) Time (minutes) Time (minutes) # Observations
1. Get ball of dough 0.010 0.12 0.15 11
2. Flatten dough 0.030 0.25 0.25 23
3. Spin and toss dough 0.040 0.50 0.60 10
4. Place dough on counter 0.005 0.12 0.15 3
5. Pour sauce on formed dough 0.035 0.30 0.30 21
6. Place grated cheese on top 0.025 0.25 0.28 16
7. Place pepperoni on sauce 0.030 0.24 0.28 25
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Work Measurement Problem 1
For a certain element of work, the Normal Time is
established to be 20 seconds. If for three observations, a
time study observer records rating of 100,125 and 80
respectively, on a 100-normal scale, what are the
observed timings?
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Work Measurement
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Problem 2
An 8-hours work measurement study in a plant
reveals the following :Units produced = 320 Nos.
Idle Time=15%.
Performance Rating=120%
Allowance=12% of Normal Time
Determine the Standard Time per unit produced.
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Work Measurement
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Problem 3
Compute the production cost per piece from following data :
(i)Direct materials cost per piece = Rs.2.00
(ii)Wage rate Rs.2000.00 per month pertaining to 25 working
days and 8 hours per day.
(iii)Overheads expressed as a percentage of Direct Labour
Cost 200%
(iv)The time for manufacture of 4 pieces of the item wasobserved during time study. The manufacture of the item
consists of 4 elements
A, B, C, and D. The data collected during the time study are as
under. Time observed (in minutes) during the various cycles are
as below :
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Work Measurement
The personal, fatigue and delay allowance may be taken as 25%
Element Cycle-1 Cycle-2 Cycle-3 Cycle-4 Element
Rating on
Scale
0-100
A 1.2 1.3 1.3 1.4 85
B 0.7 0.6 0.65 0.75 120
C 1.4 1.3 1.3 1.2 90
D 0.5 0.5 0.6 0.4 70
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Elements Average Observed
Time
NT=(OT x Observed
Rating) Standard
Rating
A (1.2+1.3+1.3+1.4)/4=1.3 (1.3x85)/100=1.105
B (0.7+0.6+0.65+0.75)/4=0.675 (0.675x120)/100=0.81
C (1.4+1.3+1.3+1.2)/4=1.3 (1.3x90)/100=1.17
D (0.5+0.5+0.6+0.4)/4=0.5 (0.5x70)/100=0.35Normal Time for the Job = 3.435
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Work Measurement
Standard Time for the Job = Normal Time + Allowances
= 3.435 + 3.435 x 0.25 = 3.435+0.858
= 4.3 minutes
As this time is the time taken for producing 4 pieces,
so, Standard Time per piece = 4.3 4 = 1.075 minutes =1.075/60 hr
=0.0179 hr
Calculation for the costLabor Rate per hour = (2000) (25x8) = Rs.10
Direct Labor Cost = (Standard Time per piece in hour) x
(Labor Rate per hour)
= 0.0179 x 10 = Re.0.18
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Work Measurement
Overhead cost = 200% of Direct Labor Cost
= 2 x 0.18 = 0.36
Total production cost per piece = Direct labor cost +
Materials cost + Overhead cost
=0.18 + 0.36 + 2.0
=Rs.2.54
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THANK YOU
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