Stop Watch Time Study:
Stop
Watch Time Study is one of the equipment used for Time Study. It is employed
for measuring the time taken by an operator to complete the work. Stop watch
used for time study purpose should be very accurate and preferably be graduated
in decimals so that it can recover even up to 0.01 minute.
The
stop watch procedures for collecting Time Study Data are listed below:
a)
Analyse the job to establish the quality to be achieved in the job.
b)
Identify key operations to be timed in the job.
c)
Get improved procedure from the method study department.
d)
Organise resources and explain the objectives of time study to the worker and
supervisor.
e)
Explain details to worker about improved working procedure.
f)
Break operation into elements to separate the constant elements from variable
elements.
g)
Observe and record the time taken by an operator.
h)
Determine for number cycles to be timed and then the average time or
representative time can be found out.
i)
Rate of performance of the worker during observation.
j)
Calculate normal time from observed time by using performance rating factor.
k)
Add process allowance rest and personal allowance and special allowances to the
normal time in order to obtain standard time or allowed time.
l)
Standard time determination by adding normal time and allowances.
Stop Watch procedure for collecting time study data
The eight basic procedures for stop watch time
study are as follows:
1. Receive the request-for time study:
The persons who may request for the time
study are: The foreman, plant manager, chief industrial engineer, production
control supervisor, cost accountant etc. the operation should be in progress in
accordance with some standard method before the receipt of the request.
2. Obtain the Cooperation of the
Departmental Foreman or Supervisor:
It the request for time study has not
been received from the departmental foreman, the time study observer should go
to the floor and explain him its necessity, uses and benefits to be derived
from its results and convince them about it. A method engineer cannot perform
the time study work successfully if he is not cooperated or he cannot have the
cooperation from the foreman or the supervision in selecting the operator.
3. Select an operator and obtain his
cooperation:
The worker to be selected for time study
purpose should be very near to the normal, if the choice is there. The operator
to be selected should have been trained before so that the standard set are
very near to the normal. Other desirable qualities of the operator (a)
cooperativeness, (b) working at normal pace, (c) have been time studied before.
However, ideal conditions seldom exist.
The observer should be introduced to the
worker to be time studied by the foreman or the supervisor. The observer should
very clearly and in plain words, explain the idea behind his motives of
observation and the benefits to be derived from his study. It is also desirable
that the observer should show the time study equipment to the worker.
The motives could be to introduce
incentives to the workers, to check the standard set whether loose or tight, to
check the performance of the worker either good or bad. The position of the
observer should be a well-balanced man having pleasing personality and fully
matured.
The analyst should treat the worker as
one sharing in investigation and should try to win his cooperation and watch
his interest. The operator should be put at ease and instructed to work at his
normal rate. The observer should avoid standing in front of or directly behind
the operator and should select a position away at one side. It is reassuring to
the operator if he can look around at the observer occasionally and furthermore
the observer may need to ask question now and then.
4. Determine whether the job or operation
is ready for time study:
In this phase the observer will check
whether the operation to be studied conform to the standard method suggested by
him or not. He will see whether some of the motions can be combined or
eliminated. If so, he will again suggest a better method. Other things which
are questionable are speeds and feeds; tools-their design and type, equipment,
quality of the product being produced, product design, safety of the operator
and equipment etc.
If the above analysis of the operation
reveals only minor desirable changes, they should be installed promptly and
after limited practice by the operator, the time observer can proceed with his
work. If the changes resulting in method improvement are major, then more time
should be devoted to install it. Proper training should be given to the
operator before the time study proceeds.
5. Obtain and record all necessary
information:
During the analysis of the operation, the
observer should collect and record all the necessary information pertinent to
the job on a time study sheet. These information are a must and are very useful
for records, setting standard and the validity, the time study made. This data
in no case should be omitted.
6. Divide the Operation into Elements and
Record Complete Description of the Method:
The general rules governing the division of
the operation into elements are:
(1) the elements should be of as short a
duration as can be accurately timed
(2) The elements should be so established
that no element will contain both a work element that is variable in time
requirement and another work element that is constant in time requirements
(3) Machine and/or process time should
always be separated and the observer must identify the starting and stopping
time of the machine on the sheet.
(4) Elements should consist of
homogeneous groups of therbligs. The elements should consist of natural
subdivisions of work, such as a series of motion with a single part,
inspections or use of tool.
(5) Irregular elements should be noted.
There are elements which do not occur regularly with each cycle of output but
are nevertheless productive elements and must be included in the observed data
and prorated over the regular time.
(6) The choice of elements may be
influenced by the ease with which break points, separating the successive
elements, can be observed or identified. This the sound or some other factors
affecting the observer’s senses can be employed to designate the end of one
element and the start of the next element with accuracy. This is important when
elements are of short duration.
Division of the operation elements is
necessary because of the following reasons:
(1) Worker’s speed of work is not
constant always even for a small duration of time. Thus, rating can be applied
to each element timed to find out the normal time.
(2) Certain elements take more time which
can only be found if the operation is divided into elements. A thorough
analysis of this element will reveal the reasons for higher times and the
necessity of its elimination and/or improvements.
(3) Finding time for each element will
help us in setting standard data. The use of this standard data in future will
save time, money, botheration etc.
(4) Division of the operation into
elements will help in future to train the new workers, new time study personnel
and various other purposes.
The description of each element should be
complete enough so that the other person picking up the time study sheet could
easily identify each element, and any other pertinent information that might be
needed to establish in future whether or not changes had occurred.
(7) Observe and Record Element Times:
Elements of an operation should be
written first in order of their occurrence on the time study sheet before the
start of the observation. When specific order of occurrence of elements is not
possible, operation should be subjected to a thorough analysis and other
symbols may be used in place of the description of the element. The description
of the element may be written at the bottom of the sheet. Break points must
clearly be written in such cases and borne in mind throughout the study.
The position of the observer as explained
earlier, should be such that he should be able to see the watch, time study
sheet and operator, his hands and the actual operation he is performing. The
observer should be instructed to be in standing position rather than sitting in
a chair. However, there may be exceptions to this like observing an office
operation, where the operator works while sitting.
The following are the commonly used methods of
reading a stopwatch:
(i) Overall Timing or Cycle Timing
(ii) Continuous Timing
(iii) Snap-back Timing or Repetitive
Timing
(iv) Accumulative Timing
(8) Present the Data:
Soon after the computation of the standard time and other necessary information’s, the time study observer should submit this report of work study either to his boss or someone else from whom he has received the request. He should not endeavor to keep it in his own drawer, wait for the order or request to submit it. This will help in pursuing the purpose fast for which time study has been made.
No comments:
Post a Comment