3.ii Method Study

3. ii Method Study

Source: Introduction to Work Study, By International Labour Office, Geneva, Chp. No. , From Pg No.

3.ii Method Study  Man, Machines, Materials, Money, Technology and Time are the main resources required to produce goods and are to be deployed in the most effective manner  We have to select the best available combination of these resources at any point of time. Method Study helps in analysing the existing methods and develop a more efficient method for future.

3.2.A Definition And Objective of Method Study Method Study is the systematic recording and critical examination of existing and proposed ways of doing work, as a means of developing and applying easier and more effective methods and reducing costs. The objectives of Method Study are : – Improvement of processes and procedures – Improvement in the design of plant and equipment – Improvement of plant layout. – Improvement in the use of men, materials and

Definition And Objective of Method Study

– Improvement in the flow of production and process. – Economy in human effort and the reduction of unnecessary fatigue. – Method Standardization – Improvement in safety standards. – Development of a better physical working environment

Working Conditions And Influence Good working conditions contribute to improvement in productivity. The following are a few – Occupational safety and health conditions – Fire prevention and protection – Layout and house keeping (5S) – Lighting and Ventilation – Noise and Vibration – Ergonomics – Arrangement of working Time

Procedure The solution of any problem follows the following sequence of phases in that order : Define: The problem. Record: All the facts relevant to the problem. Examine: The facts critically but impartially. Consider: The courses of actions (possible solutions) and decide which to follow. Implement: The solution. Follow Up: The development. The basic procedure for the whole of work study, which embraces the procedures of both method study and work measurement. Contd…

Procedure… Steps and Procedure to conduct Method Study : Select: the work to be studied. Record: all the relevant facts about the present method by direct observation. Examine: those facts critically and in an orderly sequence, using the techniques best suited to the purpose. Develop: the most practical, economic and effective method, having due regard to all contingent circumstances.

Procedure… Define: the new method so that it can always be identified. Install: that methods as standard practice. Maintain: that standard practice by regular routine checks. These are the seven essential stages in the application of method study ; none can be excluded. Strict adherence to the sequence, as well as to their content, is essential for the success of an investigation. They are shown diagrammatically on the chart.

Method Study to improve methods of production

At Work Place By means of Charts

Other Means

Select Work which can be studied With economic advantage

Method Study

Define Scope of Study

At Work Place By means of

Record Outline Process ; Two handed ; Simo ; Multiple Flow Process – Man type , Material Activity type ; Multiple Activity ; Travel Cycle Graphs ; Chronocycle Graphs Flow Diagrams ; String Diagrams ; ; Models Film Analysis ; Memotion Examine the facts Photography critically Challeng e PURPOSE – PLACE – SEQUENCE – PERSON - MEANS

Planning and Control Materials Handling General Environment and Working Conditions Plant Layout

Seek Alternatives Find Pointers Eliminat Combine or Simplify e Change Develo A record p of an improved method Re that record to Examine establish The Best Method under Prevailing Circumstances Defin e Install The Improved method Plan - Arrange Implement Maintai n Verify at regular intervals that The important method as defined is in fact in use To achieve improved factory and work space layout Improved design of equipment Better working conditions Reduction of fatigue Resulting in improved use of material Plant and equipment

Charts

Other Means

Mechanical Aids ; Manual Controls and Visual instruments Equipment design ; Jigs and fixtures Local Working Conditions

Higher Productivity

Selection Of Job Factors o be considered in selecting a job for method study: Economic Consideration. Technical Consideration. Human Reactions. Economic Consideration. The cost of the study should be estimated and examined: short-term & Long-term. The loss of time due to the investigation. For any job, if accumulated estimated benefits from the recommended method outweighs the estimated total cost then we should take-up the job under study – Discounted Cash Flow Technique (DCF) or

Selection Of Job…

Under Preliminary Considerations, the early job choices are: Bottlenecks: which are holding up other production operations. Movements of material over long distances: between shops or operations involving a great deal of manpower or where there is repeated handling of material. Operations involving repetitive work: using a great deal of labour

Selection Of Job… Technical Considerations: Make sure that adequate technical knowledge is available with which to carry out the study. Human Reactions: These are the most important factors to be taken into consideration since mental and emotional reactions to investigation, and change of method have to be anticipated.

The Field Of Choice Types of Jobs Complete Sequence of manufacture

Examples Manufacture of an electric motor from raw material to dispatch Transformation of thread into cloth from preparation to inspection Receipt, packing and dispatch of fruit

Factory layout : Movements of a diesel engine movement of cylinder head through all machining materials operations. Movements of grain between milling operations

Recording Technique Outline process chart Flow process chart Flow diagram

Outline process chart Flow process chart– material type Flow diagram Travel chart Models

The Field Of Choice… Types of Jobs

Examples

Recording Technique

Factory layout Labourers servicing spinning : movement of machine with bobbins workers Cooks preparing meals in a restaurant kitchen

Flow process chart-man type string diagram String diagram

Handling of materials

Putting materials into and taking them out of stores Loading lorries with finished products.

Flow process chart – material type Flow diagram String diagram

Workplace layout

Light assembly work on a bench Typesetting by hand

Flow process chart-man type. Two-handed process chart. Multiple activity chart. Simo chart. Cyclegraph. Chronocyclegraph.

The Field Of Choice… Types of Jobs

Examples

Recording Technique

Gang work or automatic machine operation

Assembly line Operator looking after semiautomatic lathe

Multiple activity chart Flow process chartequipment type

Movements of operatives at work

Female operatives on short – cycle repetition work Operations demanding great manual dexterity

Multiple activity chart Flow process chart – equipment type Films Film analysis Simo chart Memotion photography Micromotion analysis

The Field Of Choice… When selecting a job for method study it will be found helpful to have a standerdised list of points to be covered as shown below :-

1. 2. 3. 4. 5.

Product and operation Person who proposes investigation Reason for proposal Suggested limits of investigation Particulars of the job a) How much is produced or handled per week?

The Field Of Choice…

a) What percentage (roughly) is this of the total produced or handled in the shop or plant? b) How long will the job continue? c) Will more or less be required in future? d) How many operatives are employed on the job i. Directly? ii. Indirectly? e) How many operatives are there in each grade and on each rate of pay?

The Field Of Choice… a) How is payment made? (team-work, piece-work, premium bonus time rate, etc) b) What is the daily output – i. Of the best operative? ii. Of the worst operative? c) When were production standards set? d) Has the job any especially unpleasant or injurious features? Is it unpopular i. With workers ? ii. With supervisors ?

The Field Of Choice… 1. Equipment.

a) What is the approximate cost of plant and equipment? b) What is the present machine utilisation index? 2. Layout a) Is the existing space allowed for the job enough? b) Is extra space available ? 3. Product. a) Are the frequent design changes causing modifications ? b) Can the product be altered for easier manufacture ?

The Field Of Choice…

1. What savings or increase in productivity may be expected from a method improvement ? a) Through reduction in the work content of the product or process. b) Through better machine utilisation. c) Through better use of labour Contd…

The Field Of Choice… It is important to set clearly defined limits to the scope of the investigation Method study investigations so often reveal scope for even greater savings that there is a strong temptation to go beyond the immediate objective  This should be resisted, and any jobs shown up as offering scope for big improvements through method study should be noted and tackled separately. “Do not use a spoon when a steam shovel is needed”

Record, Examine, Develop After selecting the work to be studied Systematic recording of all the existing method and critical examination of these are carried out to eliminate every unnecessary element or operation and to develop the quickest and best method by having an improved sequence of doing the work, omitting the redundant elements, selecting more appropriate person and more suitable place for doing the work. Is to record all the facts relating to the existing method. The success of the whole procedure

Record, Examine, Develop… because they will provide the basis of both the critical examination and the development of the improved method. It is therefore essential that the record be clear and concise. The usual way of recording facts is to write them down. Unfortunately, this method is not suited to the recording of the complicated processes which are so common in modern industry.

To overcome this difficulty other techniques or `tools’ of recording have

Record, Examine, Develop… precisely and at the same time in a standard form, in order that it may be readily understood by all method study men, in whatever factory or country they may be working. The most commonly used of these recording techniques are charts and diagrams. There are several different types of standard charts available, each with its own special purposes.

Record, Examine, Develop… Two groups of charts :

Those which are used to record a process sequence, i.e., a series of events or happenings in the order in which they occur, but which do not depict the events to scale; and Those which record events, also in sequence, but on a time scale, so that the interaction of related events may be more easily studied.

Record, Examine, Develop… The most commonly used method study charts and diagrams A. Charts

Indicating process SEQUENCE Outline Process Chart Flow Process Chart – Man Type Flow Process Chart – Material Type Flow Process Chart – Equipment Type Two – Handed Process Chart

B. Charts

Using a TIME SCALE Multiple Activity Chart Simo Chart

C. Diagrams

Indicating movement Flow Diagram String Diagram Cyclegraph Chromocyclegraph Travel Chart

3.ii.B Symbols used in Method Study The recording of the facts about a job or operation on a process chart is made much easier by the use of a set of standard symbols, which together serve to represent all the different types of activity or event likely to be encountered in any factory or office. The two principal activities in a process are operation and inspection.

Process Chart Symbols… Operation Indicates the main steps in a process, method or procedure. Usually the part, material or product concerned is modified or changed during the operation.

Inspection Indicates an inspection for quality and / or check for quantity

Transport Indicates the movement of workers, materials or equipment from place to place

Process Chart Symbols… Temporary Storage or Delay

Indicates a delay in the sequence of events : for example, work waiting between consecutive operations, or any object laid aside temporarily without record until required.

Permanent Storage

Indicates a controlled storage in which material is received into or issued from a store under some form of authorization; or an item is retained for reference purposes.

Combined Activities

Indicates a controlled storage in which material is received into or issued from a store under some form of authorization; or an item is retained for reference purposes.

3.ii.C

The Outline Process Chart

The Outline Process Chart An outline process chart is a process chart giving an overall picture by recording in sequence only the main operations and inspections.

In an outline process chart, only the principal operations and the inspections carried out are recorded to ensure effectiveness While preparing the outline process chart we use Symbols of Operation and Inspection A brief note of the nature of each operation is made beside the symbol

Example Assembling a switch rotor

Switch Rotor Assembly The operations and inspections carried out on the spindle made from 10mm Ø steel rod are as follows O 1 Face, turn, undercut and part off on capstan lathe (0.025 hrs) O 2 Face opposite end on the same machine(0.010 hrs). Transport to inspn dept I 1Inspect for dimensions and finish (no time fixed). Transport to milling section O 3 Straddle mill four flats on end on a horizontal miller (0.020 hrs). Transport to work bench O 4 Remove burrs at the burring bench(0.020 hrs). Transport to inspn dept I2 Final inspn of machine (no time)

O5 Degreasing(0.0015 hrs) O6 Cadmium plating(.008 hrs) I3 Final check (no time) O7 Face on both sides, bore the cored hole and ream to size on a capstan lathe(0.080 hrs) O8 Drill cross-hole and burr on two-spindle drill press(0.022 hrs) I4 Final check dimensions and finish (no time) Transport to finished parts stores and await withdrawl for assembly. Note the numbering of operations and inspections

Outline process chart

Outline process chart In making an outline process chart we start with a vertical line down the right hand side of the page to show the operations and inspections undergone. The time allowed per piece is also shown on the left hand side.

3.ii.D

FLOW PROCESS CHART Process activity symbols – Operation – Inspection – Transport – Temporary storage or Delay – Permanent storage

Process chart symbols Used to represent different types of activities or events. Very convenient, widely understood type of short hand, saves a lot of writing and helps in making the sequence of activities clear.

3.ii.D Flow process chart

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A FLOW PROCESS CHART records what the worker does. It is a chart setting out the frequency of flow of a product or procedure by recording all events under review using process chart symbols. there are different types of flow process charts. Purpose: To set out the sequence of the flow of a

Activities recorded in the flow chart Those where some thing is happening to the work piece. Those where the work piece is not touched – (stored or standstill)

Three types of flow process charts Man type – Flow chart which records what the worker does

Material type – Flow chart which records how material is handled or treated

Equipment type – Flow chart which records how the equipment is used

FLOW PROCESS CHART FOR ENGINE Stripping – Cleaning - Greasing

Critical Examination The questioning technique is the critical means by which the critical examination is conducted – each activity being subjected in turn to a systematic and progressive series of questions

OPERATIONS Make Ready Do Put Away Make ready and put away operations can be represented by transport and inspection symbols DO operations can be shown by “O”

CRITICAL EXAMINATION - Primary questions The Purpose The Place The sequence The person The means

for which… at which… in which… by which… by which…

…the activities are undertaken

CRITICAL EXAMINATION - Primary questions With a view to Eliminating Combining Rearranging Simplifying …those Activities

PRIMARY QUESTIONS PURPOSE PLACE SEQUENCE PERSON MEANS

ELIMINATE COMBINE REARRANGE REARRANGE SIMPLIFY

THE SECONDARY QUESTIONS Definition The secondary questions cover the second stage of the questioning technique, during which the answers to the primary questions are subjected to further query to determine whether possible alternatives to place, sequence, persons and/or means are practicable or preferable as the means of improvement up on the existing method

SECONDARY QUESTIONS… During the second stage of questioning, we should address – What else might be done? – What should be done?

Purpose Place Sequence Person Means

These questions are the basis for a systematic method study.

EXAMPLE: ENGINE Stripping – Cleaning - Degreasing

DEVELOP IMPROVED METHOD After critically examining and sequential questioning we develop the improved method and record the improved method in a flow process chart as shown

TOOLS USED FOR PREPARING PLANT LAYOUTS 

String diagram



Flow Process chart



Travel Chart



Flow diagram



Multiple activity chart



Template Models

3.ii.D.1 String diagram

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String diagram is a useful tool to record the distance traveled by a worker in the working area. The string diagram is a scale plan or model on which a thread is used to trace and measure the distance traversed which has to be minimum by •Workers •Material or •Equipment

during a specified sequence of events

Observe the clusters of points, pins, turning points. Also observe the grid lines which represent a measure of the distance between the points.

Construction of a String diagram Step-1 – Preparing a study chart

Step-2 – Drawing a scale plan of the working area

Step-3 – Combining steps 1,2 to construct the final diagram

Step-1: Preparing a study chart Worker being studied is followed and all the points along the working areas are noted in a study sheet until a representative picture of the workers is obtained. Thus the movements are noted down for enough number of cycles so as to capture the actual work in terms of the journey made by the worker with their respective frequencies.

Step-2: Drawing a scale plan of the working area Machines, benches, stores and all other points at which calls are made are drawn to scale together with doorways, pillars etc that effect the path movements. Then attachments like soft wood, composition board and pins are driven firmly at every point. Pins are driven also at turning points on the route. This ensures a shop floor environment which helps to do the study accurately.

Step-3: Combining the steps 1 and 2 A measured length of thread is wound from the starting point of the movement of the worker and leading through all the points on the path of the worker in the same order noted in the step1 This results in a String diagram.

Example of a String diagram Movement, Transport of tiles from Inspection to Storage

IMPROVED METHOD

Serving dinners in a hospital ward

FPC - Dinners in a hospital ward

Original Flow Diagram Inspn and Marking

Improved FD of Inspection and Marking

3.ii.D.iii Travel chart

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A travel chart is a tabular record for presenting quantitative data about the movements of workers, materials or equipment between any number of places over any given period of time.

Why Travel chart ?  Although the string diagram is a neat and

effective way of record the movement of worker or material for critical examination, o o

they take long time to construct look increasingly like a complex maze with increasing complexity of movement paths

When the movement patterns are complex, the travel chart is quicker and more manageable to record.

More about Travel chart Always a square A column at (m,n) is checked only when there is a direct movement from station at m to station at n directly. The number of times a column at (m,n) is checked over a period of time gives the frequency of movement of a worker or material. The matrix is always a symmetrical matrix.

Travel chart

3.ii.D.4 FLOW DIAGRAM While the flow process chart describes the flow of a product or process, it is generally supplemented with a flow diagram. While the flow process chart records travel distances and time taken for various operations, the flow diagram is a plan , drawn to scale of the work area, correctly indicating the position of machines and working positions. The symbols are also indicated in the flow diagram. The example shown indicates the flow diagram of receiving, inspection, marking and storing materials. After recording examining and developing a new method, the improved flow diagram shows the transport operations reduced from a 11 to 6. delays from 7 to 2. and the distance travelled reduced from 56.2 to 32.2

Original Flow Diagram Inspection and Marking

Improved FD of Inspection and Marking

3.ii.E.

MULTIPLE ACTIVITY CHART Multiple activity chart is a useful recording tool for situations where the work involves the interaction of different persons. Such as the operator working on different machines. In Mac a time scale is used. Mac can be used effectively even if there is no movement of workers involved in the work under consideration. Focus on Mac in situations where the operator are moving and to identify the idle time of the worker or the machine

Multiple activity chart A MULTIPLE ACTIVIITY chart is a chart in which the activities of more than one subject (worker, machine or item of equipment) are each recorded on a common time scale to show their inter relationship. By using separate vertical columns or bars, to represent the activities of different operatives or machines against a common time scale, the chart shows very clearly periods of idleness on the part of any of the subjects during the process.

Inspection of catalyst in a converter The following slides show the present method of inspecting catalyst in a convertor where teams of electrician and mate, fitter and mate, rigger and process man are working together. In the original method it took 6 mins for the inspn. After recording, critically examining and developing a new method, the inspection time is reduced to four minute,ie a 32% saving.

MAC-Inspn of catalyst in a converteroriginal method

MAC-Inspn of catalyst in a converterImproved method

3.ii.F TEMPLATE MODELS Template models are used to study the layout and the positioning of various machines by pasting templates on the plant layout diagram. This can be extended by using the string diagram technique to visualize the flow of the material.