INSTITUTE NAME – GOVT. POLYTECHNIC, HISAR

BRANCH – MECHANICAL ENGG.

SEMESTER – 6 TH

SUBJECT – INDUSTRIAL ENGG.

SUBJECT CODE – 120361

TEACHER NAME – SH. PAWAN KUMAR BALODA

Industrial Engineering

1. Productivity

1.1 Productivity

It is a measure of the efficiency of a person, machine, factory, system, etc., in converting inputs into useful outputs. Productivity is computed by dividing average output per period by the total costs incurred or resources (capital, energy, material, personnel) consumed in that period.

Productivity = Output / Input

1.2 Factors Affecting Productivity

The various factors which affect productivity are mentioned below:

1. Man Power:- Selection i.e. selection of right man for a specific job Applying well known saying division of labour. Training i.e. consideration of training requirements whether to be imparted training in the plant itself or to be sent for training outside the unit to other plants within the country or abroad or training institutes. Number of personnel required i.e. man power requirement planning in each of the departments of required skill.

2. Equipment and Machines:- The number of machine tools, their capacity and accessories required, replacement policy of the organization and maintenance schedules etc.

3. Input Materials:-

i. Appropriate quality of materials

ii. Material requirement planning (M.R.P.)

iii. Substitute of materials being used

iv. Inspection of input materials at various points

v. Cost of materials procurement and handling up to stores.

4. Time:-

Time is significant for the following reasons:

i. Inspection of input materials i.e. raw material and semi finished or finished items required for assembly.

ii. Time for inspection of finished products.

iii. Production time (total time of manufacturing).

iv. Time for repair and maintenance of machines and equipment.

5. Floor Area or Space:-

i. Total area covered by the administrative block, production shop and inspection & quality control departments etc.

ii. Location of different departments and shops etc.

iii. Other space covered by plant layout.

6. Power or Energy:-

i. Maintenance of equipment for saving energy

ii. Use of renewable energy devices

iii. Use of biogas, photovoltaic cells, solar energy and other non conventional techniq

7. Finance:-

Finance is required to maintain all the above requirements. The management should be for minimum rather optimum finance.

8. Movement of Man and Materials:-

i. The required motion of manpower within the plant

ii. The motion of raw material semi finished and finished products/items within the plant.

1.3 Importance of Productivity

Is there anyone in the world who does not believe production is important? That is the whole point of a firm, to produce things for profit. However, there is always more to the story. Productivity, if it is just reflected in profits and losses, forgets the whole picture. Productivity is about people, about work, about the shop floor, not just numbers in a ledger. Productivity is about labor, and labor is necessary, intelligent and hopefully rewarding work. Productivity increases output. High productivity results in lower cost per unit of output resulting in higher levels of profit for a business. For example, a factory worker can produce 10 items in an hour and he subsequently produces 20 units in the same hour after some training. His productivity has doubled and the business will benefit from a fall in unit cost as more units are being produces at the same costs of production.

Higher profits for the firm will mean more funds available for its expansion, new business ventures and community support. It may also wish to pass on the benefits of lower costs to consumers in the form of lower prices.

1.4 Measurement Of Productivity

Measure of Productivity Kendrick and Creamer19 the authors consider that a company's productivity can be measured and analysed in basically three types of productivity indices:-

a) Total productivity index = Total Output / All input factors

b) Total factor productivity index = Net output / Total factor input

Where, Net output = output - intermediate goods and services Total factor input = Manpower input + capital input

c) Partial productivity index = Output / one factor of input

In put factors are considered as labour, capital and materials and the partial productivity index, so obtained are referred to as partial productivity of labour, partial productivity of capital and partial productivity of materials.

1.5 Causes Of Low Productivity

Following are the causes of low productivity causes of low productivity:-

1. Lack of skill:-  If employees are not skilled they can’t produce more.

2. Lack of cooperation among employees:- If one employee cooperates with other, productivity may be increased. On the other hand, if one doesn’t cooperate others, productivity decreased.

3. Lack of technology:-  If technology is not modern productivity may be affected.

4. Lack of employee training:-  Training helps an employee to increase his productivity. Lack of training is one of the causes of poor productivity

5. Relationship between employee & employer:-  If relationships between employee and employer are good productivity of the employee may be increased.

6. Lack of commitment:-  If employ are not committed to their organization and his work then productivity may not be up to the mark.

7. Physical condition of the employee:-   Generally employees’ physical condition has an positive relation with productivity. Otherwise it may be hampered.

8. Lack of concentration:-

 If the concentration of the employee is not good to his work then productivity decreases.

9. Lack of cooperation between employee & employer:-  If employer cooperates with employee they are willing to do better. On the other hand if employer doesn’t cooperate with the employees productivity decreases.

10. Lack of favorable environmental condition:-  If the environmental condition of the organization is not good, then productivity level may be less.

1.6 Methods To Improve Productivity

Before you can adopt any method for productivity improvement, you'll need to measure your existing output levels, create a baseline and implement solutions for measuring change. Shane Strowski, president of Precision Waterjet & Laser lists the following eight steps to help you design a more productive and successful manufacturing floor for your business.

1. Examine the Existing Workflow:- The first step is all about identifying pain points in your current workflow. Analyze the people, technology and processes required for production–as well as the procedures, communication tools and resources available across the company. Consider using value mapping as an effective solution for identifying and monitoring projects for process improvement; this strategy enables managers to pinpoint issues and record how changes impact the overall system.

2. Update Business Processes :-  Share current workflow problems with project managers to develop improvement plans for the manufacturing process. This could mean re-assigning resources to different areas of the manufacturing floors, managing budgets or becoming ISO certified. Be sure to systematically evaluate performance and interpret any appropriate changes.

3. Invest in Continued Employee Education :- The manufacturing, machining and cutting industries are constantly changing–there’s always a new technology promising to make manufacturing floors more efficient than ever. Technological advancements often change the skills required for certain tasks, and workers will require access to regular training to keep up with more advanced specialist skills.

4. Have Realistic Expectations :-

 Client expectations, pressures regarding production and strict deadlines can contribute to unrealistic goals. When workload benchmarks on the manufacturing floor are unattainable without some compromise to safety or quality, employees become dissatisfied, preventing the company from reaching labor goals. To boost worker efficiency, it's important to set realistic, clearly defined objectives that ensure a combination of punctuality, high-quality output and safe procedures.

5. Get Smarter Machining Tools :-  Manufacturing is an industry in which an employee can only be as productive as his or her tools. While innovative machines, such as waterjet machines or CNC mills, can be costly in terms of initial setup and training, advanced equipment can have a positive long-term effect. Manufacturing companies often find that a machinery upgrade helps them stay competitive in a new and innovative market.

6. Invest in Maintenance :-  There's a link between the costs associated with downtime and the time and budget invested into preventive measures. While new equipment can boost productivity, it also requires maintenance to ensure that it continues working at an optimum level. It is important that employees know how to troubleshoot instances of system downtime, to quickly find root causes of errors. Don't be too quick to blame the tool for problems–remember to think about the process, the blueprint, the material and more.

7. Stay Organized:-   The number of lost dollars and wasted man-hours that result from a lack of organization can be surprising. One surefire way to enhance productivity in any environment is to ensure there’s a well-organized place for everything–from materials, to machine tools and documents. When organizing your work area, think about the layout of your machining equipment and tools and whether they currently maximize efficiency. If not, consider rearranging your manufacturing floor to create a smoother workflow.

8. Encourage Collaboration :- The manufacturing floor is most productive when everyone works together towards the same goal with as little waste and conflict as possible. While focusing on work is important, it's also crucial to ensure that each staff member feels comfortable as part of a team. The better the members of your team can work together, the more they will encourage a productive workplace culture.

1.7 Difference Between Production And Productivity

Production is the process of combining units of inputs (natural, man-made and human resources) to create output (goods and services) capable of satisfying human needs and wants.

Productivity is the increase of output from each unit in the production process.  There are several ways of achieving productivity. These include the training of workers and the introduction of

machinery and equipment into the production process.

2. Work Study

2.1 Work Study Work study is a generic term for those techniques, particularly method study and work measurement, which are used in all its context and which lead systematically to the investigation of all the factors, which effect the efficiency and economy of the situation being reviewed in order to effect improvement.

2.2 Techniques Of Work Study And Their Inter-Relationship

There are two techniques of work study:-

1. Method Study :- Method study is the process of subjecting work to systematic, critical scrutiny to make it more effective and/or more efficient. It is one of the keys to achieving productivity improvement.

2. Work Measurement :- Work measurement is the application of techniques designed to establish the time for an average worker to carry out a specified manufacturing task at a defined level of performance. It is concerned with the duration of time it takes to complete a worktask assigned to a specific job .

There is a close relationship between method study and work measurement. Method study is concerned with the reduction of the work content of a job, while work measurement is mostly concerned with the investigation and reduction of any ineffective time associated with the job.

2.3Objectives Of Work Study Following are the advantages of work study:-

1. Better product quality,2. To choose the fastest method to do a job,3. To improve the working process,4. Less fatigue to operators and workers,5. Effective labour control,6. Effective utilisation of resources,7. To decide equipment requirements8. To pay fair wages.9. To aid in calculating exact delivery10. To formulate realistic labour budgeting,11. To decide the required manpower to do a job.12. Increased efficiency.

2.4Scope Of Work Study Work study has a wide scope in the following fields:-

1. Industries.2. Marketing, sales and distribution.3. Offices, stores and warehouses.4. Material handling.5. Design and development.6. Building and other constructions.7. Transport8. Hospital.9. Agriculture.10. Defence services.

2.5Advantages Of Work study The advantages of work study are the following:-

1. Work study ensures higher productivity,2. Better working conditions with less fatigue,3. Higher wages to workers,4. Uniform production flow,5. Job satisfaction and job security to workers,6. Reduction in unit cost of production,7. Quality products to consumers,8. Fast delivery schedule, 9. Harmonious employer-employee relation, and10. Better service to customers.

2.6Scope Of Work Study In Improving Production Work Study plays an important role in improving productivity which can be expressed as follows:-

1. To standardise the method of doing a work,2. To minimise the unit cost of production,3. To determine the standard time for doing a task,4. To minimise the material movement, and operators movement,5. To eliminate unnecessary human movements,6. To utilise facilities such as man, machine and materials most effectively, and7. To a systematic investigation of all factors.

3. Method Study

3.1 Method Study

Method study can be defined as the procedure for systematic recording, analysis and critical examination of existing or proposed method of doing work for the purpose of development and application of easier and more effective method.

3.2 Objectives Of Method Study

The main objectives of method study are:-

1. The improvement of processes and procedures.

2. Factory and work place layout improvement.

3. Improvement in the design of plant and equipment.

4. Reduction in unnecessary fatigue and movements.

5. Use of improved materials, machines and manpower.

6. Better Working conditions.

3.3Procedure Of Method Study

The various steps n carrying out a complete method study are as follow:

1. Selection of the Job :- The first step, once the Method Study idea is conceived, is the orientation and determination of objectives. The problem must be defined. Some common problems the Method Study investigator faces and is usually required to solve are:-

(a) Bottlenecks that disrupt smooth flow of materials or processes.(b) Products that need to be produced economically by the application of

cost-reducing techniques.(c) Economic utilization of space, including land and buildings(d) Economic utilization of labour, material and plant(e) Elimination of idle item or non-value adding time caused by problems of

flow, queues and congestion.

2. Record the Facts:-

Record all the relevant information pertaining to the existing method

(if any) in details and in the form of a chart to obtain a more clear picture about the

same.

(a) Process Charts:(i) Outline Process Chart(ii) Flow Process Chart(iii) Two Handed Process Chart(iv) Multiple Activity Chart

(b) Diagrams:(i) Flow Diagrams

(ii) String Diagrams(iii) Cycle Graph(iv) Chronocycle Graph.

(c) Metods And Film Analysis(i) Simo Charts)

(d) Models.

3. Critical Examination :Examine the recorded events critically and in sequence. Critical examination involves

answer to a number of questions. An activity can be eliminated, simplified or combined with

another.

The basic questions are:

Purpose. – What is done?

Person. – Who does it?

Place. – Where it is done?

Means. – How is it done?

Sequence. – When is it done?

4. Develop : Develop the best method as resulted from criticalexamination and record it.

The developed method should be:

(i) Practical and feasible,

(ii) Safe and effective,

(iii) Economical, and

(iv) Acceptable to design, production control, quality control and sales departments.

5. Install:

Install the (best) developed method or the improved method. Installation involves

three phases, namely-planning, arranging and implementing. During first two stages the

programme of installation (phase-wise) and a time table, are planned and the necessary

arrangements of resources, equipment, tools and instructions to workers, over-time, etc.,

are made.

The implementation or actual installation involves the introduction of developed method as

standard practice. Problems associated with the developed method should be carefully

studied and remedied, if necessary. Installation phase is complete as soon as the new

method starts working smoothly and satisfactorily and gives encouraging results (like

saving in time, scrap reduction, etc.)

6. Maintain:

Maintain the new method, i.e., ensure the proper functioning of the installed method

by periodic checks and verifications. The purpose of checks and reviews is to find if the

method being practised is the same or it has deviated from the authorised one.

Reasons for deviation if any should be explored and the necessary changes may be made in

the procedure being practised so that it reverts to the authorised one. Views of the workers,

supervisors and other persons related with the authorised method can be of much help in

exploring further improvements.

3.4Information Collecting And Recording Techniques

Record all the relevant information pertaining to the existing method (if any) in details and

in the form of a chart to obtain a more clear picture about the same.

(a) Process Charts:(i) Outline Process Chart(ii) Flow Process Chart(iii) Two Handed Process Chart(iv) Multiple Activity Chart

(b) Diagrams:(i) Flow Diagrams

(ii) String Diagrams(iii) Cycle Graph(iv) Chronocycle Graph.

(c) Metods And Film Analysis(i) Simo Charts)

(d) Models.

3.5Process Chart Symbols

The study can be carried out by preparing process chart, which is a chart to record a process in a compact manner, as a means of understanding and improving it.The process chart explains systematically the series of actions done during the work process and also gives the information graphically.The process chart is prepared based on certain number of symbols i.e. Operation. Transportation, Inspection,Delay and Storage. Sometimes few /activities may be combined also.

Operation: An operation represents the real work that is carried out, mainly the time spent on treatment to patient directly.Transportation: The staff moves certain object or moving one place to another place, except when the movement is not part of the operation and inspection.

Inspection: Inspection means a person examining the work accuracy or checking the materials required or checking and comparing with a standard as quantity or quality.

Delay: There may be some gap between activities or before performing the next action some delay due to various reasons.

Storage: Storage occurs when the activity is stopped and it is not performed.

3.6Process Charts

(i) Outline Process Chart : An Outline Process Chart surveys and records an overall picture of the process and states only main events sequence-wise. It considers only (main) operations and inspections. Actually an outline process chart is the beginning of a detailed analysis.

(ii) Flow Process Chart: A Flow Process Chart is a detailed version of outline process chart and it records all the events. (1) Sets out sequence of flow (of a procedure or product);(2) Records all the events in sequence using process chart symbols;(3) Marks distances travelled and time taken for completing an activity;(4) Mentions other important (or key) points, if any

There are three types of flow process charts, namely:(a) Flow process chart (Man) (Fig. 9.3),(b) Flow process chart (Equipment), and (c) Flow process chart (Material) (Fig. 9.2).

(a) Man Type Flow Process Chart records the activities of an operator, i.e., what an operator does.(b) Equipment Type Process Chart records the manner in which the equipment is used and(c) Material Type Process Chart records what happens to the material, i.e., the changes the

material undergoes in location or condition.

Figure 9.3 shows an example of man type flow process chart plotted otherwise:

(iii) Two Handed Process Chart: A Two Handed Process Chart records the activities of the left hand and the right hand (of an operator) as related to each other. The activities of the two hands can be synchronized by providing a time scale on the chart. Figure 9.1 shows a two-handed process chart which is also known as operator activity chart. Such a chart is generally used for repetitive works of short duration.

(iv) Multiple Activity Chart: Where a number of workers work in a group or an individual operator handles two or more machines, their activities have to be co-ordinated for achieving proper results. A multiple activity chart records simultaneously the activities of all the workers and machines on a common time scale and thus shows inter-relations between them.

Purpose of Multiple Activity Chart:

(i) To detect idle times being enforced on machines and workers,(ii) To optimise work distribution between workers and machines,(iii) To decide number of workers in a group,(iv) To balance the work teams,(v) To examine the interdependence of activities, and(vi) Ultimately, to develop an improved method of accomplishing a task and to have an effective labour cost control.

Construction of Multiple Activity Chart:

(i) A separate vertical bar or column is there to represent each subject (which may be a machine or an operator).(ii) A common time scale is provided for all the subjects.(iii) Activities of each subject in relation to those of the others are marked in the respective columns.(iv) Previously conducted time studies provide the time values for each activity.(v) A brief description of each activity is marked on the chart.(vi) Working and idle times are marked differently on the chart.Figure 9.6 shows a Man Machine Chart which is a specialized form of Multiple Activity Chart:

Analysis of Multiple Activity Chart:After constructing the chart, it is tried to:(i) Rearrange the work cycle to minimize men or machine idle times,(ii) Simplify the operations, and(iii) Combine or eliminate some of the elements etc.Applications of Multiple Activity Chart:A multiple activity chart finds applications in:(i) Plant repair and maintenance,(ii) Construction jobs, and(iii) Planning team work.

3.7Diagrams

(i) Flow Diagram: In a manufacturing shop, overhauling or a repair shop or in any other department there are movements of men and materials from one location to another. Though,

process charts indicate the sequence of events, they do not illustrate the movements of men, material, etc., while the work is being accomplished.The number of movements if minimized, result in a lot of saving both in cost as well as efforts required to do a job. The path of movement (i.e., the movement between two locations and the number of times a movement is repeated) can be better visualised by drawing a diagram; it may be a string diagram or a flow diagram. A string diagram is preferred over a flow diagram, if paths of movements are very much involved (congested) and difficult to trace on a flow diagram. A flow diagram is more suitable for simple cases.A Flow Diagram is a drawing or a diagram which is drawn to scale. It shows the relative position of production machinery, jigs, fixtures, gangway, etc., and marks the paths followed by men (workers) and materials.

Steps in drawing a flow diagram:

(1) Draw to scale the plan of the work area.(2) Mark the relative positions of machine tools, benches, store, racks, inspection booths, etc.(3) From the different observations, draw the actual (path) movements of the material or the worker on the diagram and indicate the direction of movement. Different movements can be marked in different colours (for better understanding). Process symbols may also be added on to the diagram.Figure 9.4 shows a simple flow diagram, in which, raw material from the store moves to station A where an operation is performed, the semi-finished product is sent to place B where another operation is carried out, then it moves to place C for inspection, is further sent to bench D where it halts for a short while and ultimately goes out of the factory.

(ii) String Diagram:

When the paths are many and repetitive, a flow diagram becomes congested and it is neither easy to trace it nor to understand. Under such conditions a string diagram is preferred.

String Diagram is a model or a scale plan of the shop, in which every machine or equipment is marked and a peg or pin is struck by or in the area representing a facility. A continuous coloured thread or string traces the path taken up by the materials or workers while performing a particular operation.

Construction of String Diagram:

(i) Draw the scale-layout of the shop (working) area and mark various features, such as machinery, work benches, store, etc.

(ii) Mount this scaled drawing on a soft board and strike pins or pegs at all the places which form the path of the workers and materials. More pegs may be struck in between the facilities to trace more or less, the actual path of men and materials.

(iii) A continuous coloured unstretchable string, taken from the first to the last peg, is wound to mark the path followed by workers or materials.

(iv) As many as 15 times, a thread can be taken round each peg easily and yet it will not be difficult to comprehend the various movements. The thread when measured gives approximately the total distance travelled by a worker or the material.

Figure 9.5 shows a string diagram:

Uses of String Diagram:

A string diagram picturises the movements it:

(i) Is very useful in dealing with complex movements and plant layout and design problem,

(ii) Indicates clearly, back tracking, congestion, bottlenecks, and over and under utilised paths on the shop floor,

(iii) Measures the distances involved and points out whether a work station is suitably located,

(iv) Traces existing path of movements for necessary modifications if any,

(v) Is preferred when movements are not regular as regards their frequency and distance travelled,

(vi) Shows the pattern of movements and thus helps in deciding the most economical routes to do a particular operation,

(vii) Is advantageous in studying the movements of:

(a) An individual operator handling a number of machines,

(b) A group or gang moving from one machine or work bench to another, and

(c) Workers/materials in an assembly or repair shop.

Drawbacks of String Diagram:

If the workers or materials move in some irregular or curvilinear path, it is not possible to trace exactly the same on the string diagram and thus 1.0 estimate can be made regarding the total distance travelled by the workers or the materials.

(3). Cycle Graph and Chronocycle Graph: Definition Advantage and Limitation!

These techniques were developed by Gilbreth. Both cyclegraph and chronocyclegraph records the motion path of an operator. These techniques require filming equipment. Movements which are very fast and very difficult for the human eye to trace are traced by these techniques.

In making a cycleigraph, a small electric bulb is attached to the hand, finger or any other part of body whose motion is to be analysed or recorded. Path of the light of the bulb is same as that of the body member. As bulb moves through the space for one complete cycle, path is photographed by still photograph.

The path traced by the body member is the bulb appears as white continues line in the background of the working area. However, there is no indication of the direction or speed of motion. In making a chromocycligraph, a discontinuous or intercepted power supply is given to the electric bulb. This is achieved with an interrupter of known frequency which is introduced in the electric circuit such that the light flasheds on quickly and off slowly.

The bulb is attached to the body member echoes motions are to be traced out. As a result of which, we do not achieve the continuous path. Rather, a dotted line with pear shaped dots is photographed. Usually, the frequency of interruption is 10-30 per second. More the spacing between the dots, more it is an indication of tumbling or hesitation of the body member at that point.

4. Motion Analysis

4.1 Introduction

Motion analysis is used in computer vision, image processing, high-speed photography and machine vision that studies methods and applications in which two or more consecutive images from an image sequences, e.g., produced by a video camera or high-speed camera, are processed to produce information based on the apparent motion in the images. In some applications, the camera is fixed relative to the scene and objects are moving around in the scene, in some applications the scene is more or less fixed and the camera is moving, and in some cases both the camera and the scene are moving.

4.2 Procedure Of Motion Analysis

The procedure for time study can best be described step-wise, which are self explanatory.

Step 1: Define objective of the study. This involves statement of the use of the result, the precision desired, and the required level of confidence in the estimated time standards.

Step 2: Verify that the standard method and conditions exist for the operation and the operator is properly trained. If need is felt for method study or further training of operator, the same may be completed before starting the time study.

Step 3: Select operator to be studied if there are more than one operator doing the same task.

Step 4: Record information about the standard method, operation, operator, product, equipment, and conditions on the Time Study observation sheet.

Step 5: Divide the operation into reasonably small elements, and record them on the Time Study observation sheet.

Step 6: Time the operator for each of the elements. Record the data for a few number of cycles on the Time Study observation sheet. Use the data to estimate the total number of observations to be taken.

Step 7: Collect and record the data of required number of cycles by timing and rating the operator.

Step 8: Calculate the representative watch time for each element of operation. Multiply it by the rating factor to get normal time.

Normal time = Observed time x Rating factor

Calculate the normal time for the whole operation by adding the normal time of its various elements.

Step 9: Determine allowances for fatigue and various delays.

Step 10: Determine standard time of operation.

Standard time = Normal time + allowances

4.3Principles Of Motion Economy

There are a number of principles concerning the economy of movements whichhave been developed as a result of experience and which form the basis for the development of improve methods at the workplaceThe principles are grouped into the following three categories:-

A. Use of human bodyB. Arrangement of workplace.C. Design of tools And Equipments.

A. Use of Human Body:

1. The two hands should begin and complete their motion at the same time.2. Arm movements should be symmetrical, simultaneous and in opposite directions.3. Hand and body motions should be confined to lowest classification to perform the work satisfactorily.4. The two hands should not be idle at the same time (except during rest).5. Momentum should assist the worker (otherwise reduce to minimum).6. Smooth continuous and curved movements preferable over straight-line movement with sharp changes in direction.7. Ballistic movements are (easy fast and accurate) preferred over controlled movements.8. Arrange work to provide natural rhythm where possible.9. Eye fixations should be as few and as close together as possible.

B. Arrangement of Workplace:

1. Make definite and fixed place for all tools and materials. In other words there should be a place for everything and everything at its place.

2. Locate tools materials and controls as close to the place, of use as possible.

3. Gravity feed the material to the point of use (though bins and containers).

4. Locate materials and pools to permit best sequence of operations.

5. Good illumination for satisfactory visual perception.

6. Use drop delivery where possible.

7. Arrange work place height to permit alternate sitting and standing at work.

8. Provide chair of suitable type and height to permit good posture.

C. Design of Tools and Equipment:

1. Relieve hands if the work can be economically done by jig, fixture or pedal.

2. Combine two or more tools where possible.

3. Pre-position tools/materials where possible.

4. When fingers are loaded divide work with according to the capabilities of the fingers.

5. Locate levers and handler to permit work with least change in body posture and greatest mechanical advantage.

4.4Therbligs

On analysing the result of several motion studies conducted, Gilbreths concluded that any work can be done by using a combination of some or all of 17 basic motions, called Therbligs (Gilbreth spelled backward). These can be classified as effective therbligs and ineffective therbligs. Effective therbligs take the work progress towards completion. Attempts can be made to shorten them but they cannot be eliminated. Ineffective therbligs do not advance the progress of work and therefore attempts should be made to eliminate them by applying the Principles of Motion Economy. Tablegives different therbligs along with their symbols and descriptions.

4.5SIMO CHART

It is a graphic representation of an activity and shows the sequence of the therbligs or group of therbligs performed by body members of operator. It is drawn on a common time scale. In other words, it is a two-hand process chart drawn in terms of therbligs and with a time scale, see Figure.

Making the Simo Chart. A video film or a motion picture film is shot of the operation as it is carried out by the operator. The film is analyzed frame by frame. For the left hand, the sequence of therbligs (or group of therbligs) with their time values are recorded on the column corresponding to the left hand. The symbols are added against the length of column representing the duration of the group of therbligs. The procedure is repeated for the right hand and other body members (if any) involved in carrying out the operation.

It is generally not possible to time individual therbligs. A certain number of therbligs may be grouped into an element large enough to be measured as can be seen in Figure.

4.6Ergonomics

Ergonomics is the science which deals with the relationship between man and his working environments. It takes care of factors governing the physical and mental strains. Ergonomics consists of words ‘Ergo’ (which means work), and ‘Nomos’ (which means ‘Natural Laws’). This can also be termed as ‘Human Engineering’.

Objectives of Ergonomics:

Objective of the study of ergonomics is:

1. To optimise the integration of man and machine in order to increase productivity with accuracy.2. To take care of the factors governing the physical and mental strain (i.e. fatigue) so as to get maximum satisfaction for the worker which at the same time enhances the productivity.3. Attempts to minimize the risk of injury, illness, accidents and errors without compromising productivity.4. To improve the design of machine at the initial design stage or later whenever the existing product or process is modified.

Applications of Ergonomics

Ergonomics has been applied to a number of areas as explained below:-

A. Working Environment:- Physical and psycho-social aspects of the work environment are crucial factors which affect comfort of worker and his performance. The physical factors at the workplace include lighting, ventilation, noise and temperature.Psychosocial aspects are concerned with motivational work environment, these includes working hours, rest pauses, shift systems, health and safety along-with other factors.

B. Workplace Layout:- (i) Are desks, benches and chairs suitable for the people using them and for the tasks they are performing? Poorly designed chairs which cannot be adjusted for height and to support your lower back can cause back pain. Desks which are not ergonomically designed to acomodate a range of heights can also cause discomfort and increase the risk of injuries.(ii) Are passages and exits kept clear at all times? Accidents can be caused by poor housekeeping.(iii) Is equipment with dangerous moving parts properly guarded?(iv) Are items which are manually, lifted and carried are stored and worked on at a suitable height? Well-designed storage areas and work areas can significantly reduce the amount of bending, twisting and lifting that you need to do to carry out your tasks.(v) Chemicals should be stored safely in areas located near suitable safety equipment. These should be in areas where there is adequate ventilation.

C. Other areas :- Other areas include studies related to fatigue, rest, pauses, amount of energy consumed, shift work and age consideration

4.7Design Of Workplace

Backaches, necaches, and other muscular strains due to bad seating and incorrect working posture are common in industry, where most of the jobs are performed by the operators either in sitting or standing in a fixed posture for a long duration.The interaction of the operator with the immediate workspace around him is influenced by many factors such as seat design, the working desk and adjacent machine. These factors are responsible for the position and postures of the users and, hence their efficiency.

(a) Location of Tools and Materials: All tools and materials required must be located within the normal grasp area and as far as possible in front of the worker. This will enable him to travel lesser distances to pick up and put these tools and materials frequently at desired place so as to save time and energy.For the assembly work, it is advisable to provide such arrangement so that the components can slide along the smooth surface and the worker picks them up. It will greatly reduce the time and effort.

(b) Proper Chairs: Chairs permitting proper posture for the workers must be provided. This is possible when the worker is working on the work bench (e.g. assembly, fitting and inspection etc.). Performing a job on floor in sitting position or on table in standing position requires more energy.The height of chair and the work bench must be arranged in such a way so that the worker may not feel any difficulty while working. Their height must be such that the top of bench remains at the height of the elbow of the worker. If possible the height of the bench must be such that worker can work both in sitting and standing positions. Chairs must be provided with foot rests.

(c) Working desk: All the tools and materials must be located within the normal grasp area and as close in front of the operator as possible. Experiment have shown that a semi-circular table having a radius of 20″ or 50 cm from a point at 4″ or 10 cm back (4″ or 10 cm gives approximately centre line of the operator shoulders and elbow) as shown in Fig. 53.1., allows a most comfortable position.

Working desk must be so designed so that use of both hands can be taken simultaneously.In the end, “work place layout” helps the analyst in determining the required body and eye motions of operators, safety measures and operational difficulties that may occur at working place.

Work Posture:

The posture that a workman needs to adopt to perform the task is an important consideration in the design of workplace. Incorrect posture can cause strain in back, waist, legs and hands. Ergonomic design of the seats include type of seat, seat height, back support, arm support, foot rests etc.