Work Study for management
What is work study?
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 as –“The systematic, objective, critical and imaginative examination of all factors governing the operational efficiency of any specified activity in order to effect improvement.”
Purpose of work study
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.
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 day’s work. He is protected unfair demands. The work is made easier and more productive.
* Trade union gets a reliable data measuring fair day’s work and payment 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. So the consumers are benefit.
Means of increasing productivity
There are six possible lines of attack on productivity problems, which can be classified as follows:
1. Improve basic processes by research and development.
2. Improve existing and provide better plant and equipment.
3. Simplify the product, reduce and standardize the range.
4. Improve existing methods of plant operation.
5. Improve the planning of work and the use of man-power.
6. Increase the effectiveness of all employees.
Work study as field of application
The following diagram shows how work study helps in increasing productivity –
Method study
The aims of method study are-
* Better design of plant equipment's 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.
Steps involved in method study
# 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
Method study activities
There are the following 5 method activities as described below:-
1. Operation: An operation is an action performed for advancing towards 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 a time from production.
4. Delay: A delay occurs when some undesirable event prevents/hinders the next planned activity e.g. waiting for a machine to be repaired. A traffic jam.
5. Transport: A transport occurs when there is movement from one place to another.
Method study symbols
In order to make a vivid presentation of facts, and to enable the mind to understand them quickly and clearly, we use some symbols instead of words, for the method study activities.
Recording technique
For recording data the following aids may be utilized –
Graphs.
Tables.
Schematic models.
Flow chart.
Templates.
Histogram.
Frequency polygons and ogives.
The process recording methods are –
1. Operation/Outline process chart. (What & Use-39)
2. Flow process chart. (What & Use-43 &44)
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.
Critical examination questions
The objectives of critical examination of recorded facts of an existing or proposed 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.
What, Why, What else might & Should be done ?
Place
Where, Why, Where else & Where should it be done ?
Sequence
When, Why then, When else could & When should ?
Person
Who, Why, Who else might & should do it?
Means
How, Why, How else could, How else should
Work Measurement
Work measurement is the application of techniques designed to establish the time for a qualified
worker to carry out specified jobs at a defined level of performance.
We have seen how total time to manufacture a product 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.
Introduction
Work measurement (WM) is concerned with investigating, reducing and eliminating ineffective time, whatever may be the cause.
WM is the means of measuring the time taken in the performance of an operation or series of operations in such a way that the ineffective time is shown up and can be separated out.
In practice, proving existence of the ineffective time is the most difficult task.
After existence is proved, nature and extent is easy to see!
WM is also used to set standard times to carry out the work, so that any ineffective time is not included later.
Purpose of 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.
Uses of WM
To compare the efficiency of alternative methods. Other conditions being equal, the method which takes the least time will be the best method.
To balance the work of members of teams, in association with the multiple activity charts, so that, as far as possible, each member has tasks taking an equal time.
To determine, in association with man and machine multiple activity charts, the number of machines an worker can run.
Time study
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.
Steps in making a time study
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.
At the same time assessing the effective speed of the working of the operative in relation to the observer’s concept of the rate corresponding to standard rating.
Extending the observed times to “basic times.”
Determining the allowances to be made over and above the basic time for operation.
Determining the “standard time” for the operation.
Breaking the job into elements
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….
Reasons for breakdown of job
To ensure that productive work (or effective time) is separated from unproductive activity (or ineffective time).
To permit the rate of working to be assessed more accurately than would be possible if the assessment were made over a complete cycle.
To enable different types of elements to be identified and distinguished, so that each may be accorded the treatment appropriate.
To enable elements involving high fatigue to be isolated and to make the allocation of fatigue allowances more accurate.
Reasons for breakdown of job
To facilitate checking the method and so that subsequent omission or insertion of elements may be detected quickly.
To enable a detailed work specification to be prepared.
The enable time values for frequently recurring elements, such as the operation of machine control or loading and unloading work-pieces from fixtures, to be extracted and used in compilation of the synthetic data.
Types of elements
A repetitive element is an element which occurs in every work cycle of the job.
An occasional element does not occur in each work cycle of the job, but which may occur at regular or irregular intervals. e.g. machine setting.
For a constant element, the basic time remains constant whenever it is performed. e.g. switch the machine on.
A variable element is an element for which the basic time varies in relation to some characteristics of the product, equipment or process, e.g. dimensions, weight, quality etc.
A manual element is an element performed by a worker.
A machine element is automatically performed by a power-driven machine (or process).
A governing 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.
A foreign element is observed during a study which, after analysis, is not found to be necessary part of the job.
Recording time for activities
Cumulative timing
The watch runs continuously throughout the study.
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 is recorded in the study.
Typically, most work-study persons attain fair degree of accuracy quickly when using the cumulative method.
Fly back time
The hands of the stopwatch is returned to zero at the end of each element and are allowed to start immediately, the time for each element being obtained directly.
In a comparative study of two methods carried out the Purdue University, the average error in reading the watch using the cumulative method was +0.000097 min per reading and using the flyback method was -0.00082 min per reading.
Cumulative time recording is preferred, because:
Trainees achieve reasonable accuracy more quickly.
It does not matter if element times are occasionally missed 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 is less compared to flyback time.
Workers have greater faith in the fairness as they see that no time can have been omitted.
Flyback method can have slight delays when the stopwatch is snapped back to zero at the end of each element.
Time study: Rating
Rating is the assessment of the worker’s rate of working relative to the observer’s 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 when motivated to apply themselves to their work.
This rate of working is called standard 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 for planning, 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.
Factors affecting rate of working
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.
Factors within worker’s control:
Acceptable variation in the quality of the process/product.
Variation due to worker’s ability.
Variation due to ability of mind, specifically attitude.
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.
Rating factor
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 × Rating = Constant
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.
Work content
The work content of a job or operation is defined as: basic time+ relaxation allowance+ any allowance for additional work (e.g. the part of relaxation allowance that is work related).
Standard time is the total time in which a job should be completed at standard performance – i.e. work content, contingency allowance for delay, unoccupied time and interference allowance.
Allowance for unoccupied time and interference may not be frequently included in the standard time calculations; however, the relaxation allowance is.
Standard time constituents
A contingency allowance is a small allowance of time which may be included in a standard time to meet legitimate and expected items of work or delays, precise measurement of which is uneconomical because of their infrequent or irregular occurrence.
Contingency allowance for work should include fatigue allowance; whereas the allowance for delay should be dependent on the workers.
Typically contingency allowances are very small and are 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 contingencies cannot be eliminated and are justified.
Relaxation allowance is an addition to the basic time intended to provide the worker with the opportunity to recover from the physiological and psychological effects of carrying out specified work under specified conditions and to allow attention to personal needs.
The amount of the allowance will depend on the nature of the job.
One of the major additions to the basic time.
Industrial fatigue allowance, in turn, forms a major portion of the relaxation allowance.
Relaxation allowances are also given as percentages of the basic times.
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.
Other allowances
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 to provide a satisfactory level of earning for certain level of performances under exceptional conditions.
Standard time
Now, we can add all the constituents to arrive at the standard time for a job.
Standard time = observed time + rating factor + relaxation allowance + work related contingency allowance + delay related contingency allowance.
