Industrial Engineering

1. Industrial Engineering Faculty - Er. Ruchita Joshi

2. Index Unit 1 • Productivity • Work Study Unit 2 • Plant layout and materials Handling • Replacement Analysis • Maintenance Management Unit 3 • Inventory Control • Quality Control Unit 4 • Industrial Ownership • Manpower Planning • Organization • Job Evaluation & Merit rating

3. Unit - 1 Productivity Chapter - 1

4. Productivity • Productivity is a measure of how well resources are utilized to produce output. • Productivity is a measure of output from a production process, per unit of input. • In other words Productivity may be defined as the ratio of output/input. • In engineering the ratio of output/input is termed as efficiencyhowever in production system this ratio is known as production efficiency or productivity. • Productivity can also be defined as human efforts to produce more and more with less and less inputs of resources. • According to Peter Drucker, “Productivity means a balance between all factors of production that will give the maximum output with the smallest effort”. • European productivity council defines, “Productivity is an attitude of mind. It is a mentality of progress, of the constant improvement of that which exists. It is certainty of being able to do better than yesterday and continuously.”

5. Examples of Productivity • A tailor is able to make 10 shirts from 13 meters cloth, by changing his cutting method in place of the usual 1.5 meters per shirt he used to take previously. • A farmer produces 10 more bags of wheat in a season, in the same area of land, using improved farming technique and better quality seeds. • A lathe machine tool, instead of 80 jobs being produced previously, now produces 100 jobs per day using improved material of cutting tool. • A machinist is able to produce 30 jobs per shift by attending two machines at a time, instead of 20 jobs per shift by attending only one machine at a time. • The common thing in all above is the increase of output without any change in input. Farmer produced more without change in input only by changing farming technique & using better quality seeds. Tailor is able to increase number of shirts by using only improved method of cutting, in which input (cloth) per shirt reduces and the output remains constant.

6. Production and Productivity • Production refers to absolute output while the productivity is a relative term wherein output is always expressed in terms of input. • Production is related to the activity of producing goods or service. It is a process (or system) of converting input into some useful, value added output. • The production may rise with without the corresponding rise in the productivity and vice versa. • If the input remains the same and the production of output increases there is a rise in productivity. • If the input and output are both varying & output rises in greater proportion than increase in input, there is a still rise in the level of productivity & if the output rises at a slower rate than the input there will be a fall in productivity even though there is an increase in production as a whole. • Production therefore means the output in terms of money whereas the productivity is the efficiency of production system.

7. Measurement of Productivity • Productivity is measured in following three manners: • Partial Productivity • Total Factor Productivity • Total Productivity The basic objectives behind productivity measurement is • To study performance of a system over a period of time. • To have relative comparison of different systems for a given level • To compare the actual productivity of the system with its planned productivity.

8. Partial Productivity • Partial Productivity • It may be defined on the basis of class of input being considered. • Example includes, if the labor is increased by 18% during last financial year, its effect on the increased output is represented by productivity. • It is a good diagnostic measure to identify areas where improvements may be done. Different forms of Partial Productivity

9. Total Factor Productivity • Total Factor Productivity • It is the ratio of the net output to the sum of labor and capital inputs. • This method is preferred as it is easy to compare in cross-industry context. • It involves a disadvantage as many important inputs, such as material, energy, etc. are ignored. Formula for Total Factor Productivity

10. Total Productivity • Total Productivity • It is the ratio of the total output to the sum of all inputs factors. • Since it contains all the input and output factors thus it is a more accurate representation of real economic performance of the organization. • It is easy for top management to understand the company performance. • Its study with partial productivity, reveals the focused areas of improvements. • Since it includes total factors summation hence it is difficult to generate companywide and sector wise data. • While calculating total productivity many indirect measures of input/output are ignored.

11. Productivity Index • It shows the total kinds of productivity measurements. Productivity Index

12. Ways to improve Productivity • It can be improved either by proper use of resources or by effective utilization of system or processes.

13. Ways to improve Productivity contd…

14. Production system • In order to convert the basic inputs like men, material, money, energy, information etc, into useful outputs like finished products and services a transformation process is needed. • This transformation is done through a process known as production. Thus a production system can be defined as a transformation system in which a saleable product or service is created by working upon a set of inputs given above. • Production systems are usually classified on the basis of the following: • Type of product, • Type of production line, • Rate of production, • Equipments used etc.

15. Types of Production system • The production system varies from factory to factory and from product to product. However one of the most important issues is production volume. Types of Production systems

16. Intermittent Production system In this system, the goods are manufactured specially to fulfill orders made by customers rather than for stock. • Here the flow of material is intermittent. • Intermittent production systems are those where the production facilities are flexible enough to handle a wide variety of products and sizes. • These can be used to manufacture those products where the basic nature of inputs changes with the change in the design of the product and the production process requires continuous adjustments. Considerable storage between operation is required, so that individual operations can be carried out independently for further utilization of men and machines. • Examples of intermittent system are: machine shops, hospitals, general office etc.

17. Types of Intermittent Production systemProject Production Project production where a single assignment of complex nature is undertaken for completion within the given period and within the estimated expenditure. • Generally work is carried out at the site of the work rather than in a factory. All resources such as tool, material, labor etc. reach the site itself. • Many civil engineering projects for construction or military related activities are project production. • The ship building is the example of project production

18. Types of Intermittent Production systemJob Shop Production In this system products are made to satisfy a specific order. However that order may be produced: • only once • or at irregular time intervals as and when new order arrives • or at regular time intervals to satisfy a continuous demand • Job shop production is characterized by its low production volume. • The production lot size is generally small. • Machines and methods employed should be general purpose as product changes are quite frequent. • Planning and control system should be flexible enough to deal with the frequent changes in product requirements. • Man power should be skilled enough to deal with changing work conditions. • Schedules are actually non existent in this system as no definite data is available on the product. • In process inventory will usually be high as accurate plans and schedules do not exist. • Product cost is normally high because of high material and labor costs. • Grouping of machines is done on functional basis (i.e. as lathe section, milling section etc.) • This system is very flexible as management has to manufacture varying product types. • Material handling systems are also flexible to meet changing product requirements

19. Types of Intermittent Production system Batch Production Batch methods require that the work for any task is divided into parts or operations. Each operation is completed through the whole batch before the next operation is performed. • Batch production is suited for medium volume lot of same variety. • It is commonly used to meet repeated customer orders. • Machines are grouped on functional basis similar to the job shop manufacturing. • Labor should be skilled enough to work upon different product batches. • In process inventory is usually high owing to the type of layout and material handling policies adopted. • Semi automatic material handling systems are most appropriate in conjunction with the semi automatic machines. • Normally production planning and control is difficult due to the odd size and non repetitive nature of order.

20. Continuous Production system • In this system the items are produced for the stocks and not for specific orders. • Before planning manufacturing to stock, a sales forecast is made to estimate likely demand of the product and a master schedule is prepared to adjust the sales forecast according to past orders and level of inventory. • Here the inputs are standardized and a standard set of processes and sequence of processes can be adopted. Due to this routing and scheduling for the whole process can be standardized.

21. Types of Continuous Production systemMass Production In mass production, same type of product is manufactured to meet the continuous demand of the product. Usually demand of the product is very high and market is going to sustain same demand for sufficiently long time. • As same product is manufactured for sufficiently long time, machines can be laid down in order of processing sequence. Product type layout is most appropriate for mass production system. • Standard methods and machines are used during part manufacture. • Most of the equipments are semi automatic or automatic in nature. • Material handling is also automatic (such as conveyors). • Semi skilled workers are normally employed as most of the facilities are automatic. • As product flows along a pre defined line, planning and control of the system is much easier. • Cost of production is low owing to the high rate of production. • In process inventories are low as production scheduling is simple and can be implemented with ease.

22. Types of Continuous Production systemProcess or Continuous Production Process production is characterized by tile manufacture of a single product produced and stocked in the warehouses awaiting sales. • The flexibility of such plants is almost zero as only one type of product can be produced in such plants. • Special purpose machines with built-in controls are used. • Materials handling is highly mechanized. • Typical examples of such plants are sugar, steel, cement, paper, coke, refineries, etc.

23. Unit - 1 Work Study Chapter - 2

24. Work Study • Since the beginning of human race there had always been a tendency to improve in many activities, but it has been recognized at a very later stage. • Work study is one of the most important management techniques which is employed to improve the activities in the production. • British Standard Glossary (BSG) defines, “Work study is a generic term for those techniques, particularly method study and work measurement,which are used in the examination of human work in all its contexts, and which lead systematically to the investigation of all the factors which affect the efficiency and economy of the situation being reviewed, in order to effect improvement.” • Work study is simply the study of work. It is the analysis of work into smaller parts followed by rearrangement of these parts to give the same effectiveness at a better cost. • Work study is used to associate two sets of techniques which are distinct approaches but yet interdependent. • Method Study • Work measurement

25. Work Study in a diagrammatic manner Work Measurement:

26. Method Study • British Standard Glossary (BSG) defines, “Method study is the systematic recording and critical examination of existing and proposed ways of doing work, as a mean of developing and applying easier and more effective methods and reducing costs.” • Method study is concerned with “the way in which work is done (i.e. method)”. It is used to simplify the way to accomplish a work and to improve the method of production. • Method Study aims to determine the most effective method of performing a job, the most logical layout of manufacturing facilities, the smooth flow of men and materials throughout the organization and the right placement of inspection stages to enable processing of a job through the smallest possible time and the least possible cost. • There is a continuous need for analyzing existing method even if they are developed to be most efficient and effective because best method today may not be the best method after some period.Subsequent investigations may reveal that more economical material is available, more efficient machines, tools, jigs, fixtures have been designed, better inspection methods have been evolved, more satisfactory material handling equipments can now be procured and so on.

27. Method Study - Purpose & Benefits Purpose/Benefits of method study • To evolve creatively and innovatively improvement in processes and procedures. • To determine the correct sequence of operations and avoid duplication (if any). • To improve layout, smoothen material flow, reduce backtracking and avoid obstacles. • To reduce unoccupied time of the operator and thereby obtain effective use of human efforts. • To improve utilization of the equipment and thereby reduce manufacturing cycle time per piece. • To select material of right specifications, cut down process waste, reduce defectives, and thereby reduce raw material consumption per unit of production. • TO achieve economy in human effort and reduction of unnecessary fatigue. • To develop a better physical working environment.

28. Method Study - Procedure Procedure of method study • Select - A specific job will be chosen to be examined. • Record - The current performance of the job is observed, facts are recorded and documented. The important features taken into consideration are: • Activities performed • Operators involved • Equipment and tools used • Materials processed or moved • Examine - The job is then examined and its components are challenged on their feasibility and necessity (purpose, place, sequence, method). • Develop - After this alternative methods are developed, documented and the most suitable will be selected, becoming the base for the new Work Instructions. • Install - The new method is installed as standard practice and the operators will be trained on those new Work Instructions. • Maintain - Control procedures to measure the performance, as well as preventing drifting back to previous methods of work will also be introduced.

29. Work Study - Benefits • It helps in optimum use of plant, equipment, manpower and material. • It helps in establishing the standard of performance. • It helps in developing standard work methods. • It helps in establishing the most efficient and effective utilization of human effort. • It helps in synchronizing various resources like men and machine. • It helps in the evaluation of human work. • It helps in efforts towards productivity improvement • It helps in the elimination of wasteful efforts, useless material handling, etc. • It helps in job simplification and work standardization. • It is helpful in developing plant safety schemes, equipment utilization, plant layout and conductive work environment.

30. Method Study - Procedure Selection of the Job • Selection of the jobs to be studied for methods improvement by the method study practitioner is a managerial responsibility and it (selection) may be based on economic, technical or human consideration. • Economic consideration:- It justifies selection based on economic worth (i.e. money saving potential of the job. • Technical consideration:- It identifies jobs which require studies to overcome manufacturing difficulties (excessive rejection, relaxation in prefixed performance standards, inability of the shops to stick to specified machining parameter such as speeds, feeds, depth of cut etc., inconsistent quality etc.) • Human consideration:- It is usually given weightage while introducing method study practices for the first time.

31. Method Study - ProcedureRecording of Facts • Recording by long hand (descriptive method) has its limitations, it is not recommended for use in method study. Instead, five symbols and eight charting conventions are used to record facts relating to the job under study. • Method Study Symbols • 1. Operation 3. Transport • 2. Inspection 4. Delay • 5. Storage

32. Method Study - ProcedureRecording of FactsMethod Study Symbols • Operation:- An operation occurs when there is a distinct change in physical or chemical characteristic of an object or, when there is an addition or subtraction or, when there is consumption of physical effort or, when information is given or received. An operation is represented by a circle. • Inspection:- An inspection occurs when the object is verified against predetermined standards of quality or quantity, or both. Inspection, unlike operation, does not take the object one step forward towards completion. It merely verifies whether or not the object has undergone the required operation as per specifications. Inspection is represented by square. • Transport:- An transport occurs when the object is moved from one place to another. Example- Movement of materials or trolley. Transport is represented by an arrow.

33. Method Study - ProcedureRecording of FactsMethod Study Symbols • 4. Delay:- A delay occurs when the object is held up resulting in delay in the start of next event i.e. next operation, inspection or transport. Delay is represented by a letter D. • 5. Storage:- A storage occurs when the object is kept in an authorized custody and is protected against unauthorized removal. Storage is represented by an inverted triangle.

34. Method Study - ProcedureRecording of FactsRecording Methods Information Recording Techniques: Different methods of information recording for the existing method are • Charts • Diagrams • Templates and Models • Photographic aids (Micromotion study) • Graphic Techniques (cyclegraph and choronocyclegraph)

35. Method Study - Procedure Recording of FactsRecording MethodsCharts Charts: Charts are the most popular method of recording data. The activities comprising the job are recorded by means of symbols and charting conventions. The different type of charts are. • Operation Process Chart: to give a bird’s eye view of entire process. • Flow Process Chart: • Man type (or operator process chart): Show detailed sequence of activities performed by the workman. • Material type (or product process chart): Show detailed sequence of activities performed on the materials. • Equipment type: Show detailed sequence of activities performed by the equipment. • Multiple Activity Chart: to study man machine utilization, determine number of machines to be manned by an operator and the like. • Two Handed Process Chart (Operator Chart): to study work bench layout. • Travel Chart: Study the movement of materials, men or equipment.

36. Process Chart A Process Chart is a graphic means of representing the activities that occur during a manufacturing or servicing job. There are several types of process charts. These can be divided into two groups. • Those which are used to record a process sequence (i.e. series of events in the order in which they occur) but do not depict the events to time scale. Charts falling in this group are • Operation process chart • Flow process chart – (man / material / equipment type) • Operator chart (also called Two Handed Process Chart) (ii) Those which record events in the sequence in which they occur on a time scale so that the interaction of related events can be more easily studied. Charts falling in this group are • Multiple activity chart • Simo chart

37. Operation Process Chart • Operation Process Chart: • An operation process chart provides the chronological sequence of all operations and inspections that occur in a manufacturing or business process. • An operation process chart gives the detailed step by step account of what is done to the materials from beginning of the first stage to the last (finished product stage). • Only operations and inspections performed on the material are depicted on this chart & transports, delays and storages are not included. • The operation process chart can be compared to a map of a city where one can have a fair idea of the layout of the city from its map but one cannot know from it about the lanes and by-lanes & their inhabitants.

39. Flow Process Chart • Flow Process Chart: • A flow process chart sets out the sequence of flow of work of a product, or any part of it through the section or the department or the factory by recording the events under review. • It is prepared in a manner similar to that of operation chart except that in addition to symbols for ‘operation’ and ‘inspection’, symbols for ‘transport’, ‘delay’ and storage are also shown. • Separate flow process charts are prepared for components of the assembly (usually one flow process chart is prepared for each major component of he assembly) . This implies that the operation process chart is normally in multiple lines while flow process chart is usually in a single line. • Flow process charts are of three types: product or material type (also known as product process chart) which shows the events that occur to material, the operator or man type (also known as operator process chart) that depicts the activities performed by the man, & the equipment type which exhibits the activities performed by the equipment. • An important and valuable feature of this chart is its recording of non-productive hidden costs, such as delays, temporary storages, unnecessary inspections, and unnecessary long distances traveled. When the time spent on these non productive activities is highlighted, analyst can take steps to minimize it and thus reduce costs.

42. Multiple Activity Chart • Multiple Activity Chart: • A multiple activity chart is chart on which the activities or more than one subject are recorded to indicate their inter-relationship in a given cycle. • Worker-Machine process chart and gang process chart fall in the category of multiple activity charts. • A worker-machine chart is used for recording and analyzing the working relationship between operator and machine on which he works. It is drawn to time scale. Analysis of the chart can help in better utilization of both worker and machine time. The possibility of one worker attending more than one machine is also sought from the use of this chart. • A gang process chart is similar to worker-machine chart, and is used when several workers operate one machine. The chart helps in exploring the possibility of reducing both the operator time and idle machine time.

44. Two Handed Process Chart • Two Handed Process Chart : • It is also called Left Hand – Right Hand chart or Operator Process Chart and shows the activities of hands of the operator while performing a task. • It uses four elements of hand work: Operation, Delay (Wait), Move and Hold. • Its main advantage lies in highlighting un-productive elements such as unnecessary delay and hold so that analyst can take measures to eliminate or shorten them.

46. Simo Chart • Simo Chart: • A Simo chart is another Left-Hand Right-Hand chart with the difference that it is drawn to time scale and in terms of basic motions called therbligs. It is used when the work cycle is highly repetitive and of very short duration.

48. Diagrams • Diagrams: • Every business activity requires movement of men and materials form one location to another. Every movement is not essential & some of them may be avoided by rearrangement of the facilities within the department or by changing the sequence of activities. • Operation process chart indicate the sequence of events but do not show movements while flow process charts do record movements but they do not provide a visual picture. The problems concerning movements can be better visualized by drawing a diagram which may be either a flow diagram or string diagram. • A diagram gives pictorial view of the layout of workplace or floor on which locations of different equipment, machines, etc. are indicated. The movement of subject (man or material) is then indicated on the diagram by a line or a string. The diagrams are valuable in highlighting the movement so that analyst can take steps to simplify or reduce it and thus effect saving in time or reduction in collisions / accidents. • Two types of diagrams are common: Flow diagram and string diagram.

49. Flow Diagrams • Flow diagram: • Flow diagrams are the scale plans on which the movements of an object are traced by lines. It shows the relative position of the machine tools, work benches, storage racks, inspection benches etc. on a scaled diagram on which are marked the paths followed by the workmen and materials.

50. String Diagrams • String diagrams: • String diagrams are the scale plans on which the movements of an object are traced by means of a string. Its advantage over flow diagram is that repetitive movements between work stations which are difficult to be traced on a flow diagrams can be conveniently shown on string diagram.