Method Study

Introduction to Method Study

It is a scientific technique of observing,

recording and critically examining the present method of

performing a task or a job or an operation .

Objectives of method study

• To develop an improved method to improve productivity

and to reduce operating cost.

• To reduce excessive materials handling or movement and

thereby reduce fatigue of workmen.

• To improve utilization of resources.

• To eliminate wasteful and inefficient motions.

• To standardize work methods or processes, working

conditions, machinery, equipments and tools.

Advantage of method study:

1. Work simplification

2. Improved working method (cheaper method)

3. Better product quality

4. Improved workplace layout

5. Improved equipment design

6. Better working conditions/environment

7. Better materials handling and lesser materials handling cost

8. Improved work flow

6. Less fatigue to operator

7. Optimum utilization of all resources

8. Higher safety to workmen

9. Shorter production cycle time

10. Higher job satisfaction for workmen

11. Reduced material consumption and wastages

12. Reduced manufacturing cost and higher productivity.

Factors facilitating method study

• High operating cost

• High wastage and scrap

• Excessive movement of materials and workmen

• Excessive production bottlenecks

• Excessive rejections and rework

• Complaints about quality

• Complaints about poor working conditions

• Increasing number of accidents

• Excessive use of overtime .

Method study procedure

The various steps involved are

1.Select:

Study the job , define the objective and achieve by

method study

2.Record:

Record the relevant facts to the existing methods using

the following techniques

a. Process charts

b. Diagrams

a. Process charts

1. Outline process charts

2. Operation process charts

3. Flow process charts

4. Man-machine type

5. Two handed process chart

6. Multiple activity chart

7. Simultaneous motion chart(SIMO)

8. Motion chart

9. Film analysis chart

b. Diagrams

1. Flow diagram

2. String diagram

3. Cycle diagram

4. Chronocyclegraph3.Examine

The recorded facts critically ,challenging everything

being done and seeking alternatives ,Questioning the purpose

(what is achieved?) , the means ( how it is achieved?) ,

sequence (when is it achieved?) , the place (where is it

achieved?) ,and the person (who achieves it?).

d. Develop Develop the improved method by choosing from different alternatives .The factors to be consideredare

• Cost of implementation

• Expected savings in time and cost

• Feasibility and Producibility

• Acceptance to design , production ,planning and control,

quality control , production and sales departments

• Reaction of employees to the new method

• Short term or long term implication of the alternative

e. Install

Install the new method which consists of 3 phases

1.Planning

2.Arranging

3. Implementing phases.

f. Maintain

Maintain the new method by checking its

performance and verification at regular intervals

Worker flow study / Motion study

It is the science of eliminating wastefulness ,main aim is

to find and perpetuate the scheme of the least waste method of

labour .

Micro motion study provides a valuable technique for

making minute analysis

E.g., Sewing of garments , assembling of small parts.

Fatigue ,Find.

It is also used for,

a. To study the inter-relationship among the members of

work group .

b. To study the relation between operator and the machine

with which he operates

c. To obtain the time of operation

d. To establish a permanent record of the method of doing a

job.

The study is done in 3 steps

a. When the motion begins

b. The nature of the motion

c. When the motion ends.

E g: Search , Select , Grasp , Transport Empty, Transport

Loaded, Hold , Release Load , Position , Preposition,

Inspect, Assemble , Disassemble , Use ,Unavoidable delay ,

Avoidable delay, Plan , Rest of overcoming.

Work Measurement

This is done to achieve higher labour productivity

Definition Application of technique designed to establish the work

content of a specified task by determining the time required for carrying out the task at a defined standard of performance by a qualified worker.

Qualified Worker:One who is accepted as having the necessary physical

attributes , required intelligence , education, skill , knowledge to carry work in hand to satisfying standard of safety ,quantity and quality defined by ILO ( International Labour Organisation)

Objectives :

• Improved planning and control of activities or

operations

• More efficient way to provide labour in a plant

• Reliable ideas for labour performance

• Reliable basis for labour cost control

• Basis for sound, incentive -Schemes

Benefits of Work measurement

• To develop a basis for comparing alternate methods . • To prepare realistic work schedules by accurate assessment of human work

• To set standards of performances for labour utilization • To compare actual time taken by the worker with the allowed time (standard time) for proper control of labour.

• To assist in labour cost estimation • To provide information related to estimation of tenders, fixation of selling price and assessment of delivery schedule.

Techniques of work measurement:

1.Direct Time study

2.Synthesis method

3. Analytical estimating

4.Pre – determined motion time study (PMTS)

5. Work Sampling or Activity Sampling or

Ratio delay method.

Steps in work measurement:

1. Break the job into elements.

2. Record the observed time for each element by means -of

either time study, synthesis or analytical estimating

method.

3. Establish elemental time values by extending observed

time into normal time for each element by applying a

rating factor.

4. Assess relaxation allowance for personal needs and

physical and mental fatigue involved in carrying out

each element.

5. Add the relaxation allowance time to the normal time for

each element to arrive at the work content.

6. Determine the frequency of occurrences of each element

in the job, multiply the work content of each element by

its frequency (i.e., number of time the element occurs in

the job) and add up the times to arrive at the work

content for the job.

7. Add contingency allowance, if any, to arrive at the

standard time to do the job.

Time study:

To determine amount of time required to perform a unit of work.

Definition:

ILO – “ Time study is a work measurement technique for recording times and rate of working for the elements of a specified job carried out under specified condition and for analysing The data so as to obtain the time necessary for carrying out the job at defined level of performance.

Objectives:

a) To furnish a 'basis of comparison for determining operating effectiveness.,

b) To set labour standard for satisfactory performance.

c) To compare alternative methods in method study in order to select the best method.

d) To determine standard costs.

e) To determine equipment and labour requirements

f) To determine basic times/normal times.

g) To determine the number of machines an operator can handle.

h) To balance the work of operators in production or assembly lines

i) To provide a basis for setting piece rate or incentive wages

j) To set the completion schedules for individual operations or jobs.

k) To determine the cycle time for completion of a job.

Time study by stop watch:

The steps involved are

1. Select the job to be studied

2. Select the worker to be studied

3. Conducting the stop watch time study.

Select the job to be studied

1. New job taken for production. 2. Change in manufacturing method. 3. Design change. 4. Change in raw material or components used for a job. 5. Complaint about inadequacy of allowed time. 6. For bottle neck operations. 7. When labour cost is high. 8. To establish standard time a “a basis for incentive

scheme” .9. When new tools, jigs and fixtures are used.

Select the worker to be studied Ideal worker is “Qualified Worker”

Conducting the stop watch time study.a. Obtain & record all the information about the job,

operator & working condition

b. Record the method of doing the job & break down the job into elements

Various elements are,1. Repetitive element2. Occasional element3. Constant element4. Variable element

5. Manual element6. Machine element7. Governing element8. Foreign Element

Examine the elements to ensure that the element to ensure that the most effective motions are used in the elements of job performed. Measure the actual time taken by the operator each element of the job, using a stop-watch.

Stop watch is of 3 Types

1. Non Fly Back2. Fly Back3. Split hand

Rating factor or leveling factor is determined by comparing the actual pace or speed of working with the standard pace or speed of working ( Of a qualified worker)

Rating scales : Three types

1. 60 – 80 Scale2. 75 – 100 Scale3. 100 – 133 1/3 Scale

Asses the effective speed of working of the operator with respect to the time study observer concept of the speed of working of a qualified worker who is assumed to have a standard rating

Rating assigned in the scale Level of performance

Corresponds to walking speed60-80 75-100 100-1331/3

0 0 0 No activity Nil

40 50 67 Very slow, clumsy, no interest to do the job

2mph

60 75 100 steady, unhurried performance

3mph

80 100 1331/3 Businessmen- like, brisk, performance of a qualified worker

4mph

100 125 167 Very fast, incentive motivated

5mph

Rating Factor =Rating of the observed workerRating of the qualified worker

Determination of normal or basic time:

Normal or basic Time = Observed time X Rating factor

= Observer time X Observed Rating

Std Rating

Determine the relevant allowances1. Relaxation allowances (RA)2. Contingency allowance(CA)3. Process allowance4. Special Allowance

Determine the standard time by adding the relevance allowances to the normal or basic time

Std time = Normal time + all relevant allowances

Synthesis Method

Technique of work measurement for building up the time required to do a job at a defined level of performance by synthesizing or totalling elemental time values obtained from previous time studies or other similar job elements

Std Data

Catalogue of “Normal” or “Basic” time values for different elements of job

Advantages of Synthesis Method

1. Reliable as the built-up time values of the 'standard data' catalogue, are based on data derived from a large number of time studies.

2. Economical as less time is required when compared to 'stop-watch' time study

3. Used for estimating labour times for preparing cost estimates for new jobs for which the selling price has to be quoted to customers.

Application

1. To estimate standard time for new jobs

2. To estimate production time for determining the prices of products to be sold

3. Used as a basis for designing incentive schemes.

Analytical Estimating

Used to determine the time values for job having long and non repetitive operations

Procedure of Analytical Estimating

(a) Find out the job details such as job dimension, standard procedure to do the job, and the job conditions, such as poor illumination, high temperature, hazardous environments, . availability of jigs, fixture or tools, etc.,

(b) Break the job into its elements

(c) Select time values from the standard data catalogue for as many elements as possible. (i.e,. use synthetic data wherever available)

(d) Estimate the time values for the remaining elements (for which synthetic data is not available) from past knowledge and experience

(e) Add the time values obtained by steps (c) and (d) to get the total 'Basic‘ or 'Normal' time (for 100% rating)

(f) Add the appropriate blanket relaxation allowance (say 10% to 20% of total normal or basic time). Note that in analytical estimating, the relaxation allowance is not added to time values of individual elements. The blanket relaxation allowances-depends on the type of the job and the job condition.

(g) Add any other allowances if applicable, to arrive at the standard time for the given job.

Advantages of Analytical Estimating Technique (a) Offers the same advantages enjoyed by synthesis

method.

(b) Helps in planning and scheduling the production. (c) Provides a basis for fixing the labour rate for non-repetitive jobs. (d) Steps to improve labour control

Disadvantages

This relay upon the judgment of the estimator, the time values obtained may not be as accurate and reliable as that estimated by the stop watch time study

Applications of Analytical Estimating Technique (i) For non-repetitive jobs, jobs having long cycle times

and jobs having elements of variable nature. For such jobs the stop-watch time study proves to be uneconomical.

(ii) For repair and maintenance work, job production, one time large projects, office routines, tool room jobs and engineering construction works.

Predetermined Motion Time System (PMTS)

Defined as a work measurement technique by which normal or basic times are established for basic human motions and these time values are used to build up the time for a job at a defined level of performance

Advantage of PMTS

1. Affords fine analysis and improvement of work methods.

2. Since the time for each basic motion is predetermined. the computation of standard time for a job or an operation is faster and more economical than time study using stop watch.

3. Offers a precise means of recording time, avoiding subjective judgment or bias of the rater.

4. Involves no interference in the normal work routine and hence faces little resistance from workers

5. More effective and economical tool for work measurement for repetitive jobs of short duration.

Disadvantages

1. Such standards are not available for each and every human activity

2. Limited to only uninhabited work in its application, i.e. for the work whichdoo8 not involve motions, restricted by the process

3. Has limited application in non-repetitive and office activities.

4. Fairly long period of intensive training under expert guidance is necessary to use this technique.

Types of Predetermined Motion Time Systems

(i) Methods of Time Measurement (MTM) : In this method, predetermined time values for basic motions or therbligs such as reach, move, turn, apply pressure, grasp, etc.. are established in terms of TMU's (i.e. Time measurement Units).

1tmu = 10-5 hours = 0.00001 hour or 0.0006 minutes or 0.036 seconds

Application of MTMs Techniques 1. Developing effective methods in advance of beginning

the production.2. Improving existing methods3. Establishing standard time data4. Estimating labour time and cost. 5. Training supervisors to be method conscious. 6. Choosing between alternative methods.

ii. Work Factor

It is based on basic motions which are modified elements of difficulty, all of which tend to make movements slower. These features or work factors are weight or resistance, change of direction, need for care, stopping a motion & manual control, each of these features is known as a “Work Force”

iii. Basic Motion Times (BMT)

The times were derived from laboratory experiments & were carefully checked against a variety of factory operation before being accepted for general use. BMT data is based on basic motions

Basic motions are classified as : figure, hand and arm motions

Class A – Without use of muscular control in stopping the motionClass B – Stop using muscular controlClass C – stop by use of muscular control both to slow down the motion

5. Work Sampling or Activity Sampling or Ratio Delay method

The random samples the work of one or more employees are periodic interval to determine the proportion of total operations that is accounted for in a particular activity

Use of work sampling technique

1. To estimate the percentage of a protracted time period consumed by various activity states of a resource such as equipment, machines or operators.

2. To determine the allowances for inclusion in standard times.

3. To indicate the nature of the distribution of work activities within a gang operation.

4. To estimate the percentage of utilization of groups of similar machines or equipment.

5. To indicate how materials handling equipments are Ming used.

6. To provide a basis for indirect labour time standards.

7. To determine the productive and non-productive utilization of clerical operations.

8. To determine the standard time for a repetitive operation as an alternative to the stop

Work sampling procedure

The works study engineer takes a great number of observation of a worker / machine random times throughout the working shift or day

The technique is based upon the laws of probability

P = X

N=

No of observations of the activity

Total no of observations

Steps in work sampling1. Determine the objective of the study, including definitions

of the states of activity to be observed. 2. Plan the sampling procedure including:

a) An estimate of the percentage of time being devoted to each phase of the activity

b) The setting of accuracy limits c) An estimation of the number of observations required d) The selection of the length of the study period and the

programming of the number of readings over this period

e) The establishment of the mechanics of making the observations, the route to follow and the recording of data

3. Collect the data as planned. 4. Process the data and present the results.

Principles of work sampling

N = C2 P(1-P)

(SP)2Or

C2 P(1-P)

E2Or

C2 PQ

E2

Where

P -> Percentage or true proportion of activity or idling which is being observed based on pilot study

S -> Relative error of the true proportion “P”

C -> Constant values 1, 2 & 3 corresponding level of 68.3%, 95% and 99% respectively

Advantages of Work Sampling1. Economical to use and Usually costs considerably less

than a continuous time study 2. Can be used to measure many activities that are

impractical to measure by time study 3. Not necessary to use a trained work measurement

analyst to make the observations. 4. Work sampling measurements may be made with a pre-

assigned degree of reliability 5. Measures the utilization of people and equipment

directly 6. Eliminates the necessity of using stop-watch for

measurements. 7. Provides observation over a sufficiently long period of

time to decrease the chance of day to day variation affecting the results

Limitations of Work Sampling 1. It is of little value in helping to improve work methods

and does not offer some of the opportunities for methods analysis that accompanies time study methods.

2. Statistical work sampling may not be understood by workers

3. If random sampling is not done, the results may be biased.