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SUBMITTED TO: PRESENTED BY:DR.A. BHARDWAJ ANIL KUMAR SHARMA (2011PMM5023) (PROFESSOR MNIT) DEEPAK KUMAR BAIRWA(2011PMM5060)

DEVESH SHARANPANDEY (2011PMM5061) (M.TECH.I SEM,MSE)

A

PRESENTATION

ON

“STRING DIAGRAMS

&

TRAVEL CHARTS”

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CONTENTS Introduction Names of charts string diagram Definition sample example When to use it How to understand it How to do it Practical variations Process Movement study sheet Analysis

Travel charts Introduction Examples Critical examination Important points Advantages

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INTRODUCTION There are many types of workers move at irregular

intervals between a numbers of points in the working area, with or without materials this situation occurs very often in industry and commerce and even in the home.

In manufacturing concerns. It occurs when.  Bulk material is being fed to removed from continuous

process and is stored around the process . An operative is looking after two or more numbers. Labours are delivering materials to or removing work

from a series of machines or workplaces.

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OUTSIDE MANUFACTURING OPERATIONS, EXAMPLES

OF ITS OCCURRENCE ARE:

In stores and shops where a variety of materials are being removed from or put away into racks or bins;

In restaurants and canteen kitchens during the preparation of meals.

In control laboratories where routine tests are carried out at frequent intervals.

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METHOD STUDY CHARTS AND DIAGRAMS

Charts indicating process sequence

- Outline process chart

- Flow process chart – Man, Material and Equipment type

- Two-handed process chart

Charts using a time scale

- Multiple activity chart

- Simo chart

• Diagrams indicating movement - Flow diagram - Chronocyclograph - String diagram - Travel chart - Cyclograph

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STRING DIAGRAM IS THUS A SPECIAL FORM OF FLOW DIAGRAM IN WHICH A STRING OR THREAD IS USED TO MEASURE DISTANCE BECAUSE OF THIS IT IS NECESSARY THAT THE STRING DIAGRAM BE DRAWN CORRECTLY TO SCALE WHEREAS THE ORDINARY FLOW DIAGRAM WILL PROBABLY BE DRAWN ONLY APPROXIMATELY TO SCALE WITH PERTINENT SCALE MARKED ON IT SO THAT SCALING OFF IS

NECESSARY .

STRING DIAGRAM

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“

Sample string diagram

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STRING DIAGRAM

Thus, it is a special form of flow diagram in which a string or thread is used for measuring the distance traveled. The string diagram is started exactly in the same way as all other

method studies : by recording all the relevant facts from direct observation. This may be achieved by using a simple “movement study sheet”. The observation and hence the recording

continues until the work study man becomes sure the obtained facts give the true picture of the situation.

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STRING DIAGRAM: WHEN TO USE IT

When analyzing a manual or physical process. Involves significant physical movement. To make movements easier and quicker. Use it when designing the layout of a work area. To identify the optimum positioning of machines and

furniture.

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STRING DIAGRAM: HOW TO UNDERSTAND IT

What positioning will make the work easier? The result is that subsequent work requires

much more moving about than is necessary. It can be difficult to 'see' what movement

will be necessary. Tool by which movement can be minimized. The basic diagram simply consists of a map

of the work area

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EXAMPLES

A metal worker became fed up with walking what seemed to be half-way around the machine room just to build a metal box. With help from the works facilitator, he measured the distance he travelled to build one box, using a pin board and scale map of his workshop area, as below. Using this, he simply moved the machines into a U-shape. the result was an easier and faster process, which also used less floor space.

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Other examples

A self-service restaurant team measures the route taken by customers around the food counters and also identifies the most popular meals that they are building. They rearrange the counters and food to enable a logical progression for the most common meals. They also include complementary and high-margin food in this line, which helps to increase the profitability of the restaurant.

A traffic planning department uses a helicopter to spot the routes taken by a sample of vehicles passing through the town, plotting the lines on a street map. Common destinations and routes are now easily identified (along with short-cuts taken through residential areas). As a result, some roads are widened, others are blocked and signs erected. The result is a much smoother traffic flow.

A maintenance team measures the route taken by engineers making routine checks on key equipment throughout the plant, plotting it on a site plan. They are then able to plot a much shorter route to each of the same machines.

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EXAMPLES

A self-service restaurant team measures & improve profit.

A traffic planning department uses a helicopter to spot the routes .

A maintenance team measures the route taken by engineers.

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HOW TO DO IT

Identify the process to be analyzed.

Produce a scale map of the work area.

Add all machines, furniture and other equipment to the diagram.

Identify the points in the process.

Tie the end of a piece of string to the pin where the process starts.

Mark the string at the start and finish points, using a pen. If more

than one worker’s movement use another color of thread .

If more than one worker’s movement use another color of thread .

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HOW TO DO IT

Rearrange the movable items on the map.

Repeat steps. Check that it is feasible to move

equipment as planned

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Strategies for deciding layouts

Mobility. Rearrange items and movements around fixed or immovable items, such as heavy machines.

Function. Put machines or people together that perform the same function. This is useful when varying loads may be shared between machines.

Product. Put machines or people together that make the same product. This works well when each machine is used for only one product.

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PRACTICAL VARIATIONS

String Diagram easier to complete in comparison to flow

diagram .

This requires less resources only map and single sheet of

paper.

It is less flexible for redesigning.

Do multiple plots on the same diagram.

Use colored pins to indicate different action.

Use colored string to show different plots.

If it is significant, add the time taken for each movement.

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PRACTICAL VARIATIONS

Annotate the diagram with pertinent notes to help

interpretation

A Topological Movement Chart represents locations

as small circles and movement as lines between

them.

Use colored string to show different plots.

If it is significant, add the time taken for each

movement.

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STRING DIAGRAM

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ANALYSIS Examination of diagram and development of new

layout. Pins and templates are moved for minimum

movement between them. This can be checked by leading the thread around

the pins in their new positions. Length of thread is measured and compared with

original thread. Difference in length of threads represent the

reduction in distance traveled as a result of improved layout.

TRAVEL CHART Also Called as Cross Chart Recording techniques in work study It is a tabular record for presenting

quantitative data about the movement of workers, materials or equipment between any number of places over any given period of time.

Quicker and more manageable techniques It is easy to study It is represented as square matrix.

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EXAMPLE: MOVEMENT OF MESSENGER IN OFFICE

we want to record the movements of a messenger delivering papers to the various work stations in an office.

There are 10 work station in office for which layout is given below:

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So we draw a chart having 10 columns and 10 raw so it will have 10x10=100 small square.

Than we draw a diagonal line from top left to bottom right. Than we assign no. 1 to 10 from left to right and top to bottom Square from left to right represent the place from where

movement takes place. Study person will indicate mark in square to show a

movement.

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After completing all the tick mark for each movement , we count all tick marks and write sum in respective square.

Than sum for both column and row is written in summary section of chart

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By studying the summary we find the heaviest traffic route .

The summary tells us that, the heaviest traffic is on the route 5-2-9.

As a result we bring these stations closer to improve method of work.

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OTHER APPLICATION

The travel chart can also be made to indicate the weight/material moved per trip.

It is also useful technique for plant layout and materials handling analysis studies.

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EXAMPLE :WEIGHTED TRAVEL CHART, MATERIAL HANDLING

There are 9 work station in the mixing department out of which 8 are mixing machines and finally work station 6 is inspection machine.

The mixtures are transported in 25-litre cans which are placed on pallets and moved by a low lift truck.

Here we will study both the movement and material moved in a mixing dept.

Now we will record all movement and no. of canes moved in study sheet

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Now we will make travel chart similarly the previous example

Here we note that 29 trips were made out which 7 were without any load.

Chart shows that station 6(inspection bench) & station 9 are busy routes

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CRITICAL EXAMINATION

5 trips were made to station 6 with total of 150 canes being delivered

8 trips were made into station 9 , to deliver 170 canes

So the largest no of trip & more quantity of canes were between 6 & 9

So by studying layout we will reduce distance between 6 &9 as per possible.

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STATİONS 2 & 6 : A POİNT İMPORTANT TO OBSERVE

It is interesting to note that, four trips were made from station 2, but only three into the station.

Similarly, only four trips were made from station 6, although five trips were made into it.

This is because the study started at station 2 and finished at station 6.

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ADVANTAGES OF CHARTS &DIAGRAMS

ADVANTAGES:- Beautiful and neatly constructed

diagrams/charts are more attractive then simple figures.

Comparison is made easy and it will save time of the user to make quick comparison of large work.

You can record comparison between two things or objects.

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REFERENCES

1. George Kanawaty, Introduction to work study , Fourth edition, International labour office ,1992,109

2. M.Mahajan, Industrial Engineering & Management, Third edition,Dhanpat Rai & co. New Delhi,2004,714

3. Harold A. Bolz, George Edward ,Materials handling handbook, Volume 1,Third edition 3, Hageman Ronald Press Co. 1958

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THANKS