PROJECT REPORTON

IMPORTANCE OF PRODUCTION SYSTEMS

1

INDEX

1) Introduction

2) Factors Influencing Manufacturing System

3) Classification Of Manufacturing System

4) Intermittent Production System Project

Job

Batch

5) Continuous Production System Mass

Flow

Process

6) Just In Time Production System

2

INTRODUCTION

Production is a conversion function by which goods and services are produced. A typical production system comprises of three main components: Inputs, Transformation process and Output.

(i) Inputs are men, materials, machines, instructions, drawings, and paper work and instructions.

(ii)The Transformation Process involves operations, mechanical or chemical, to Change/convert inputs into outputs. It also includes activities that assist conversion,

Typical examples are —

• Planning and control of factors of production.

• Procurement of materials.

• Receipt, storage and issue of materials.

• Material handling (to move materials to the point of use.)

• Inspection of ill-process and parts.

• Assembly and testing of products.

• Storage of finished goods.

• Instructions, authorizations, inspections, information storage/retrieval etc.

(iii) Output is goods and services (e.g. products, parts, paper work, served customers etc.

3

The combination of operations and activities stated above employed to create goods and services are known as manufacturing system. A manufacturing system therefore may be looked upon as an independent group of sub-systems, each sub-system performing a distinct function. Different sub-systems may perform different functions, yet they are inter-related and require to be unified to achieve overall objectives of the organization.

Manufacturing system needs to interact with both internal and external environment. The internal environment is the combination of engineering, marketing, personnel and accounts activities whereas external environment comprises of customers, competitors, suppliers, labor unions etc.

The selection of the manufacturing system is a strategic decision for most organizations since changes at a later date arc very expensive to make. The systems selected should be such that it can give the desired output, required quality and is cost-effective.

4

FACTORS INFLUENCING CHOICE OF MANUFACTURING SYSTEM

There is no best manufacturing system for any product. The choice of the system depends on various circumstances but it must meet two basic objectives, namely -

(i) It must be able to meet the specifications of the final product, and

(ii) It must be cost effective

The product specifications can be met by choosing the right technology but that is not always an easy task. Since stricter specifications add to the cost of the product, there is always a trade off between the desired specifications and the cost to achieve such specifications. For example, sophisticated injection moulding machines and high quality plastics can produce excellent dolls cheaply provided they are produced in volume. However, if their demand is limited, they may not be able to compete with “home made” dolls produced in small quantities and sold at a fraction of the price of the moulded version.

Various factors which determine the choice of the manufacturing process are as follows:

(a) Effect of volume/variety

One of the major considerations in the process selection is the volume/variety of the products.

5

Relationship between degree of repetitiveness & transformation Process

High product variety require highly skilled labour, general purpose machines, detailed production planning and control system.

On the other hand low product variety (i.e. one or few products produced in large volumes) enables the use of low skilled labor, highly automated mass production processes using special purpose machines and simple production planning and control systems.

Fig. exhibits the relationship between output and the transformation process. The horizontal axis shows the degree of repetitiveness represented in terms of batch size, one end showing the products produced in batches of one and other end representing products produced in very large batch sizes.

The vertical axis represents the transformation process, the top representing the project form where each project is followed by another (no two projects being alike) and the bottom representing the process form where the single product with highly continuous material flow (e.g. as in refinery, sugar mill) is produced.

Shaded area in each bar suggests the manufacturing system desirable for the indicated volume. Unshaded area in the lower portion of the column implies that it is inadvisable to use the continuous form when the batch is really small. Similarly, when the batch is really large, it is not at all advisable to use the project form.

For these reasons, decisions involving process selection must be taken while formulating the corporate strategy of the firm

6

(b) Capacity of the plant

The projected sales volume is a major influencing factor in determining whether the firm should go in for intermittent or continuous process. Fixed costs are high for continuous process and low for intermittent process while variable costs are more for the intermittent process and less for continuous process. Intermittent process therefore will be cheaper to install and operate at low volumes and continuous process will be economical to use at high volume.

Effect of volume on manufacturing process selection

(c)Flexibility

Flexibility implies the ability of the company to satisfy varied customers requirements. Flexibility and product variety are inter-related. If more variety is to be manufactured, the manufacturing facilities will have to be commonised and depending upon the volume, the extent of commonalities will require to be justified. Greater commonalities demands intermittent manufacturing which is associated with higher inventories, large manufacturing lead times and elaborate planning and control.

7

(d) Lead time

Lead times more appropriately called delivery lead times expected by the customers (i.e. how soon the demand has to be met without losing on sales) is another major influencing factor in a competitive market. As a general rule, faster deliveries are expected in a competitive market. The product, therefore, may require to be produced to stock using principles of batch production/mass product

(e)Efficiency

Efficiency measures the speed and the cost of the transformation process. Efficiency is the greatest when the product is mass producted. But to mass produce a product, greater sales volumes are required. Therefore, depending upon the sales volume, product variety will have to be considered and the process which will give the best efficiency in terms of machine and manpower utilization will have to be selected.

(f)Environment

Environment brings in new technologies and forces the adoption of new process of manufacturing. For example, wooden furniture is gradually being replaced by metals and plastic. A furniture manufacturing unit will have to change its technology (i.e. change from one off production to batch production) to fall in line with changing times. Similarly, as market preferences change due fashions or other reasons, the manufacturing process has to be changed accordingly.

8

CLASSIFICATION OF MANUFACTURING SYSTEMS

Classification of manufacturing system

INTERMITTENT 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

9

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.

Chief characteristics of intermittent system are: -(i) Most products are produced in small quantities

(ii) Machines and equipment are laid out by process.

(iii) Workloads are generally unbalanced.

(iv) Highly skilled operators are required for efficient use of machines and equipment.

(v) In-process inventory is large.

(vi) Flexible to suit production varieties.

Planning and Control Mechanism for Intermittent System : -

Organization of production planning and control operations in intermittent systems needs estimation of jobs, routing, scheduling, preparation of manufacturing orders, dispatching and production control.

Here customer provides the blue print and other specification regarding the product to be manufactured. Then the organization formulates their production strategy to suit the needs of the customer.

(i) This type of manufacturing system covers specialties of every type and sub assemblies or parts which are required to manufacture the product. Due to this there is continuous planning at each fresh order.

10

(ii) Due to variety of orders and different lot sizes, the system needs wise and careful sequencing of operations which makes routing and scheduling operations elaborate and complex.

(iii) Proper regulation and close inspection is required at different stages of production.

(iv) Storage facilities are to be provided at each operational stage.

So the job of stock control of raw materials, semi-finished goods and finished goods should be entrusted to competent personnel, who can regulate the operations and flow of material smoothly.

Intermittent systems can be further classified into two categories, namely

(a) Project production

Project production where a single assignment of complex nature is undertaken for completion within the given period and within the estimated expenditure.

(b) Job production

Jobbing production where one or few units of a product are produced to customer’s requirement within the given date amid within the price fixed prior to the contract.

(c) Batch production

Batch production where limited quantity of each type of product is authorized for manufacture at a time.

CONTINUOUS SYSTEMIn 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.

11

After setting of master production schedule, a detailed planning is carried on. Basic manufacturing information and bills of material are recorded. Information for machine load charts, equipment, personnel and material needs is tabulated. In continuous manufacturing systems each production run manufactures in large lot sizes and the production process is carried on in a definite sequence of operations in a pre-determined order. In process storage is not necessary which in turn reduces material handling and transportation facilities. First in first out priority rules are followed in the system. In short, here the input-output characteristics are standardized allowing for standardization of operations and their sequence.

Production Control Mechanism for Continuous manufacturing system: -In this system the control mechanism is not as elaborate and complex as for intermittent system. In continuous system large quantities of standardized products are produced using standardized production process.

Following points of control mechanism are worth noting for such a system

(i) This system does not involve diverse work, due to which routing standardized route and schedule sheets are prepared.

(ii) In case of standard products meant for mass production, master route sheets are prepared for more effective co- ordination of various departments.

(iii) Scheduling is required to rate the output of various standard products in their order of priority, operations and correct sequence to meet sales, requirements.

(iv) Work relating to dispatching and follow-up is usually simple. Dispatch schedules can be prepared well in advance in such systems. Continuous system can be divided into two types of production, namely

12

(A) Mass & (B) Process production.

Mass and flow production where a production run is conducted either on a single machine or on a number of machines, arranged according to the sequence of operations and several number of a product are manufactured at a time and stocked in warehouse awaiting sales.

INTERMITTENT PRODUCTION SYSTEM

PROJECT PRODUCTION

Project production is characterized by complex sets of activities that must be performed in a particular order within the given period and within the estimated expenditure. Where output of a project is a product, such products are generally characterized by immobility during transformation. Operations of such products are carried out in “fixed position assembly type of layout” which can be observed in production of ships, locomotive and aircraft, construction of roads, buildings, etc.

Characteristics of Project Productio n : -

(A) Definite beginning and definite end

Each project has a definite beginning and a definite end.

(B) “Fixed position” layout

Where the output of a project is a product, such products are generally characterized by immobility during transformation. Operations on such products are carried out in “fixed position assembly type of layout” which

13

can be observed in production of ships, locomotive, aircraft, construction of roads/ buildings, etc.

(C) High cost overruns

Often delays take place in the completion of the projects. Such delays are generally very expensive due to escalation in the cost of factors of production and incident of penalties.

(D) Personnel problems

Project production has many personnel related problems namely:

• When there is a fast build up, staff is either borrowed from other departments or hired for short duration. Therefore, personnel involved in the project have limited (or short lived) interest in the project.

• Since each project has a limited duration, the staff starts spending more time forgetting prepared for the next project.

•Site for the project may be in the underdeveloped region and it may change from project to project which causes dislocation of the normal life.

Importance of Project Productio n: -

(A) Non -uniform requirement of resources

Requirement of resources for project production is not uniform. At the end of the project, resources from the project are redeployed elsewhere in other projects. Even during the life of the project, requirement of resources is not uniform. Generally resource requirement (men, materials, money, etc.) in the beginning of the project is low which builds up fast with the progress of the project as more and more resources are absorbed, and then it levels off until there is gradual cutback as the project approaches completion.

(B) Involvement of different agencies

A project generally involves many tasks, each having its own specialization to be performed by different agencies. The tasks generally have strict

14

precedence (i.e. certain tasks must be completed before the next begins) amid as such co-ordination between agencies is of utmost importance.

(C) Scheduling and control

Because of large number of activities, involvement of different agencies and strict precedence requirements, scheduling and control assumes great importance. Some network planning techniques like PERT and CPM have been found to be very useful to overcome the problems mentioned above.

JOB PRODUCTION

Jobbing production is characterized by the manufacture of one or few numbers of a single product designed and manufactured strictly to customer’s specifications, within, the given period and wit/tin the price fixed prior to tile contract. Some typical examples of industries engaged in jobbing production are: general repair shops; special purpose machine tool manufacturers; workshops to manufacture jigs and fixtures for other units; building contractors; tailoring shops manufacturing made-to-measure suite of clothes; manufacturers of ships, cranes, furnaces, turbo-generators, pressure vessels; and others manufacturing articles made to customers orders.

Characteristics of Job production

(A) Disproportionate manufacturing cycle time

A considerable amount of pre-planning and organization is necessary in such a venture. Relatively long delays occur at the assembly as well as at the materials processing stages due to lack of materials or components, imbalanced work flow, design changes, design errors detected during manufacture, inaccurate work measurements, etc. which tend to lengthen the manufacturing cycle time. At times, tile time needed to design the product exceeds its manufacturing time.

(B) Large work-in-progress

15

The work-in-progress inventory in a jobbing production is generally very large as detailed scheduling and progress control in this type of production is economically infeasible. For various reasons, jobs get delayed causing temporary work shortages. To overcome work shortages and keep men and machines busy, more work is released to the shops which in turn increases work-in-progress.

(C) Limited functions of production planning and control

The success of jobbing production mainly depends on the ability of the engineer incharge of the contract.

(D) Materials are indented and purchased on receipt of orders unlike in batch or mass production where material requirements are planned well in advance.

(E) Process planning activity is almost absent. Drawings and specifications are directly given to the supervisor who is expected to decide work methods, select optimum process, fix up machine tools to be used and estimate time required completing an operation.

Importance of Job productio n: -

(A) Small production runs

Jobbing production is characterized by the manufacture of one or few pieces of a product at a time under a separate contract, the production is made strictly to customers’ specifications.

(B) Discontinuous flow of materials

The flow of materials and components between different stages of manufacture is highly discontinuous due to imbalance in operation wise work content.

(C) General purpose machines and process layout

Plant and equipment is designed or procured and arranged to obtain maximum flexibility. General purpose machines and handling equipments

16

capable of performing variety of operations with minimum set-tip times are installed in lie of variety in products. Tile machines are arranged to give process layout - layout by function. Similar machines, capable of doing similar type of operations, are grouped together. Presses, for example are kept at one place; milling machines are placed at another place; drilling machines are kept at third place; and so on and so forth. Each group of machines is usually designated as a work centre or a section or a shop.

The grouping of machines gives a lot of flexibility in loading and scheduling. Temporary machine breakdowns and operator’s absenteeism can be taken care of by shifting jobs to another machine or shifting operators from less important jobs to important jobs.

(D) Highly skilled labour

The labor force is usually highly skilled-highly qualified trade apprentices who are expected to work from minimum instructions. Instructions regarding “what to make” are issued in the form of specifications while instructions as to “how to manufacture” are usually oral. The workmen being highly skilled are expected to work independently and display a great deal of initiative and judgment. They are required to set up their own machines and prepare their OW special tools or production aids in order to further the manufacture of a part or a assembly.

(E) Highly competent knowledgeable supervision

Highly competent general engineers are engaged as foreman in the base workshop and a group of site engineers, practical men, with thorough training, capable of taking independent charge of each contract are employed to work at site. Therefore, these engineers (supervisors) in a jobbing production are the reservoir of job knowledge. The supervisor besides being able administrator is expected to improvise and determine best work methods, determine tool requirements, select the best process and provide management with reliable estimates of labor and materials for specific orders. The span of control - the number of workmen to be supervised by a supervisor - is kept low because of technical nature of the job.

(F) Simple Mechanism

Tools control function is simple. Standard tools are stocked while special tools are either made on the shop floor by the operators or purchased on request from supervisor.

(G) Decentralized Process

17

The scheduling activity is more or less decentralized. A schedule is prepared to show the start and completion date of each major component of the product. Job tickets giving completion date of each component are raised and given to the shop. The activity of day to day scheduling is left to the individual shop supervisor.

EXAMPLE OF JOB PRODUCTION SYSTEM

Job production involves firms producing items that meet the specific requirements of the customer. Often these are one-off, unique items such as those made by an architect or wedding dressmaker. For an architect, each building or structure that he designs will be different and tailored to the needs of each individual client.

With job production, a single worker or group of workers handles the complete task. Jobs can be on a small-scale involving little or no technology. However, jobs can also be complex requiring lots of technology.

With low technology jobs, production is simple and it is relatively easy to get hold of the skills and equipment required. Good examples of the job method include:

Hairdressers

Tailoring

Painting and decorating

Plumbing and heating repairs in the home

High technology jobs are much more complex and difficult. These jobs need to be very well project-managed and require highly qualified and skilled workers. Examples of high technology / complex jobs include:

Film production

Large construction projects (e.g. the Millennium Dome)

Installing new transport systems (e.g. trams in Sheffield and Manchester)

ADVANTAGES

18

The advantage of job production is that each item can be altered for the specific customer and this provides genuine marketing benefits. A business is likely to be able to ‘add value’ to the products and possibly create a unique selling point (USP), both of which should enable it to sell at high prices.

DISADVANTAGES

Whether it is based on low or high technology, Job production is an expensive process as it is labour intensive (uses more workers compared to machines). This raises costs to firms as the payment of wages and salaries is more expensive than the costs of running machines.

BATCH PRODUCTION

Batch production is characterized by the manufacture of a limited number of product (but many such, quantities of different products) produced at regular intervals and stocked in warehouses as finished goods (or finished parts,) awaiting sales (or withdrawal for assembly). Typical examples of batch production are : Process industries such as pharmaceuticals, paints, chemicals; medium and heavy engineering industry engaged in the manufacture of electric motors, switch gears, heavy motor vehicles, internal combustion engines; manufacturers of ready made garments; manufacturing and assembly shops such as machine tools; sub-contractors which take on machining of batches of components to the drawings of a large manufacturer.

Batch production is used to produce or process any product in groups that are called batches, as opposed to a continuous production process, or a one-time production. An example of batch production can be found in a bakery. The products, for example bread, are made in batches of however many will fit in the baker's oven at a time. When that batch is made, the baker will start the process again with a new batch. Batch production techniques are used in the manufacture of specialty chemicals such as active pharmaceutical ingredients, inks, paints and adhesives.

In the manufacture of inks and paints, a technique called a color-run is used. A color-run is where one manufactures the lightest color first, such as light yellow followed by the next increasingly darker color such as orange, then

19

red and so on until reaching black and then they start over again. This minimizes the cleanup and reconfiguring of the machinery between each batch. White (by which is meant opaque paint, not transparent ink) is the only color that cannot be used in a color run due to the fact that a small amount of white pigment can adversely affect the medium colors.

There are inefficiencies associated with batch production. The production equipment must be stopped, re-configured, and its output tested before the next batch can be produced.

Time between batches is known as 'Down Time' where the factory would make seasonal items or consumables such as toasters where no one can predict the quantity needed.

There are several advantages of batch production; it can reduce initial capital outlay because a single production line can be used to produce several products. As shown in the example, batch production can be useful for small businesses who cannot afford to run continuous production lines. Also, companies can use batch production as a trial run. If a retailer buys a batch of a product and people do not buy them then the producer can cease production without having to sustain huge losses. Other types of production include: assembly line, job production, continuous, cell, and project.

Characteristics of batch production: -(A) Supervisor to possess knowledge of a specific process

The supervisors have considerable knowledge of a specific process. Supervisor in the grinding section for example, may not know about turning and drilling work but is expected to P055C55 a fund of knowledge of different types of grinding operations. Similarly, a supervisor in the gear shop is expected to have sound knowledge in working of different types of gear cutting machines.

(B) General purpose machines and process type of layout

Plant and equipment is procured and arranged to obtain maximum flexibility. General purpose machines and handling equipments capable of performing variety of operations with minimum set-lip tunes are installed in lieu of variety of products. The machines are arranged to give process layout- layout by function. Similar machines capable of doing similar types of operations are grouped together and kept at one place. Presses, for

20

example, are put together and kept at one place, milling machines are placed together at another place, drilling machines are kept at the third place, and gear cutting machines are located at the fourth place and so on. Each group of machines is usually designated as a work centre or a section or a shop.

(C) Manual materials handling:

Materials handling in batch production as compared to jobbing production are small. Individual components and parts arc placed in trolleys or in bins and are transported as unit loads. Materials handling may be mechanized by deploying power driven trucks.

(D) Manufacturing cycle time affected due to queues

The manufacturing cycle time is comparatively smaller than jobbing production but is much more than mass and flow production. The batches of work tend to queue up at different machines due to differing cycle times, batch sizes and sequence of operations.

(E) Large work-in-progress

Work in progress is comparatively large due to varying work content of different components, imbalances in manufacturing times, formation of queues between the machines.

(F) Need to have production planning and control

Functions of production planning and control in a batch production unit are more complex than those in jobbing production or mass and flow production.

• Materials control and tools control functions are important. Scientific stock-control system needs to be used to ensure routine replenishment.

• Detailed operational layouts and route sheets are prepared for each part of the product.

• Lo and scheduling needs to be more detailed and more sophisticated since

every machine requires to be individually scheduled.

• Progressing function is very important to collect information on progress of work.

A separate progress card needs to be maintained to record progress of each component.

• Expediting is generally necessary since quite often jobs, due to imbalances in work content, tend to lag behind.

21

Importance of Job production: -(A) Short runs

Batch production is also characterized by short production runs and frequent changes of set up. The equipment and the assembly set up is used for a limited number of parts or assemblies and is then changed to make. a different product. The production is generally made to stock.

(B) Skilled labor in specific trades

The labor force is expected to possess skill in one specific manufacturing process turning, milling, drilling, welding, grinding, hobbing, filling etc. Simpler machine set-ups may be performed by the operator but those involving complex operations arc set by the separate machine setter.

(C) Limited span of control

The amount of supervision required in batch production is lower than that of jobbing production and is dependent of the batch size. The ratio of direct workmen to supervisors is more or less a function of batch size. The smaller the batches, the lower are the ratio of direct workers to supervisors, and vice-versa. This is because smaller lots require each supervisor to spend a great deal of their time in allocating new work, giving instructions, follow up n the shop floor for proper movement of materials from and to the machines, identifying delays and interruptions, and arranging, in consultation with planning, work load in his section to keep his men busy.

(D) Flexibility of production schedules

Disruptions due to machine breakdowns or absenteeism do not seriously affect production as another machine can be used or another operator from another machine can be shifted.

EXAMPLE OF BATCH PRODUCTION SYSTEMAs businesses grow and production volumes increase, the production process is often changed to a “batch method”. Batch methods require that a group of items move through the production process together, a stage at a time.

For example when a bakery bakes loaves of wholemeal bread, a large ball of wholemeal dough will be split into several loaves which will be spread out

22

together on a large baking tray. The loaves on the tray will then together be cooked, wrapped and dispatched to shelves, before the bakery starts on a separate batch of, for example, crusty white bread. Note that each loaf is identical within a batch but that loaves can vary from batch to batch.

Batch production is a very common method of organising manufacture. Good examples include:

Production of electronic instruments

Fish and chip shops

Paint and wallpaper manufacturers

Cereal farming

ADVANTAGES

The batch method can be an advantage for businesses that produce a range of products. It is cheaper to produce a number of each item in one go because machines can be used more effectively, the materials can be bought in bulk and the workers can specialize in that task. There are two particular advantages of workers being able to concentrate their skills.

They should become more expert at their tasks, which will in turn increase productivity (output per worker). This will lower costs, as fewer workers are needed to produce a set amount.

Better quality products should be produced as workers are more familiar with the task and so can find ways of improving it.

DISADVANTAGES

Batch production requires very careful planning to decide what batch will be produced when. Once a batch is in production it is difficult to change, as switching to another batch takes time and will mean a loss of output. Batch methods can also result in the build up of significant “work in progress” or stocks (i.e. completed batches waiting for their turn to be worked on in the next

23

operation). This increases costs as it takes up space and raises the chance of damage to stock.

CONTINUOUS PRODUCTION SYSTEM

MASS PRODUCTIONStandardization is the fundamental characteristic of this system. Here items are produced in large quantities and much emphasis is not given to consumers orders. In fact the production is to stock and not to order. Standardization is there w.r.t. materials and machines. Uniform and uninterrupted flow of material is maintained through pre determined sequence of operations required to produce the product. The system can produce only one type of product at one time.

These days, mass production system is generally used to manufacture sub-assemblies or particular parts/components of an item. These parts are assembled together by the enterprise to get the final product. One distinct advantage of this approach is that different combinations of sub-assemblies or parts can be used to manufacture different kinds of products. Specialization and standardization in manufacturing single component also leads to economies in production and product diversification to meet specific demands of consumers.

Mass production is the name given to the method of producing goods in large quantities at low cost per unit. But mass production, although allowing lower prices, does not have to mean low-quality production. Instead, mass-produced goods are standardized by means of precision-manufactured, interchangeable parts. The mass production process itself is characterized by mechanization to achieve high volume, elaborate organization of materials flow through various stages of manufacturing, careful supervision of quality standards, and minute division of labour. To make it worthwhile, mass production requires mass consumption. Until relatively recent times the only large-scale demand for standardized, uniform products came from military

24

organizations. The major experiments that eventually led to mass production were first performed under the aegis of the military.

Machine tools and interchangeable parts The material basis for mass production was laid by the development of the machine-tool industry--that is, the making of machines to make machines. Though some basic devices such as the woodworking lathe had existed for centuries, their translation into industrial machine tools capable of cutting and shaping hard metals to precise tolerances was brought about by a series of 19th-century innovators, first in Britain and later in the United States. With precision equipment, large numbers of identical parts could be produced at low cost and with a small work force.

The system of manufacture involving production of many identical parts and their assembly into finished products came to be called the American System, because it achieved its fullest maturity in the United States. Although Eli Whitney has been given credit for this development, his ideas had appeared earlier in Sweden, France, and Britain and were being practiced in arms factories in the United States. During the years 1802-08, for example, the French émigré engineer Marc Brunel, while working for the British Admiralty in the Portsmouth Dockyard, devised a process for producing wooden pulley blocks by sequential machine operations. Ten men, in place of 110 needed previously, were able to make 160,000 pulley blocks per year. British manufacturers, however, ignored Brunel's ideas, and it was not until London's Crystal Palace exhibition of 1851 that British engineers, viewing exhibits of machines used in the United States to produce interchangeable parts, began to apply the system. By the third quarter of the 19th century, the American System was employed in making small arms, clocks, textile machinery, sewing machines, and a host of other industrial products.

The assembly line. Though prototypes of the assembly line can be traced to antiquity, the true ancestor of this industrial technique was the 19th-century meat-packing industry in Cincinnati, Ohio, and in Chicago, where overhead trolleys were employed to convey carcasses from worker to worker. When these trolleys were connected with chains and power was used to move the carcasses past the workers at a steady pace, they formed a true assembly line (or in effect a "disassembly" line in the case of meat cutters). Stationary workers concentrated on one task, performing it at a pace

25

dictated by the machine, minimizing unnecessary movement, and dramatically increasing productivity.

Drawing upon observations of the meat-packing industry, the American automobile manufacturer Henry Ford designed an assembly line that began operation in 1913. The result was a remarkable reduction of manufacturing time for magneto flywheels from 20 minutes to five minutes. This success stimulated Ford to apply the technique to chassis assembly. Under the old system, by which parts were carried to a stationary assembly point, 12 1/2 man-hours were required for each chassis. Using a rope to pull the chassis past stockpiles of components, Ford cut labour time to six man-hours. With improvements--a chain drive to power assembly-line movement, stationary locations for the workmen, and work stations designed for convenience and comfort--assembly time fell to 93 man-minutes by the end of April 1914. Ford's methods drastically reduced the price of a private automobile, bringing it within the reach of the common man. (see also Index: automotive industry ) Ford's spectacular feats forced both his competitors and his parts suppliers to initiate his technique, and the assembly line spread through a large part of U.S. industry, bringing dramatic gains in productivity and causing skilled workers to be replaced with low-cost unskilled labour. Because the pace of the assembly line was dictated by machines, the temptation arose to accelerate the machines, forcing the workers to keep up. Such speedups became a serious point of contention between labour and management, while the dull, repetitive nature of many assembly-line jobs bored employees, reducing their output.

Effects on the organization of work. The development of mass production transformed the organization of work in three important ways. First, tasks were minutely subdivided and performed by unskilled workers, or at least semiskilled workers, since much of the skill was built into the machine. Second, manufacturing concerns grew to such size that a large hierarchy of supervisors and managers became necessary. Third, the increasing complexity of operations required employment of a large management staff of accountants, engineers, chemists, and, later, social psychologists, in addition to a large distribution and sales force. Mass production also heightened the trend toward an international division of labour. The huge new factories often needed raw materials from abroad, while saturation of national markets led to a search for customers overseas. Thus, some countries became exporters of raw materials and importers of finished goods, while others did the reverse.

26

In the 1970s and '80s some countries, particularly in Asia and South America, that had hitherto been largely agricultural and that had imported manufactured goods began industrializing. The skills needed by workers on assembly-line tasks were easily acquired, and standards of living in these developing countries were so low that wages could be kept below those of the already industrialized nations. Many large manufacturers in the United States and elsewhere therefore began "outsourcing"--that is, having parts made or whole products assembled in developing nations. Consequently, those countries are rapidly becoming integrated into the world economic community.

Mass production (also called flow production or repetitive flow production) is the production of large amounts of standardized products on production lines. It was popularised by Henry Ford in the early 20th Century, notably in his Ford Model T. Mass production is notable because it permits very high rates of production per worker and therefore provides very inexpensive products. Mass production is capital intensive, as it uses a high proportion of machinery in relation to workers. With fewer labour costs and a faster rate of production, capital is increased while expenditure is decreased. However the machinery that is needed to set up a mass production line is so expensive that there must be some assurance that the product is to be successful so the company can get a return on its investment. Machinery for mass production such as robots and machine presses have high installation costs.

One of the descriptions of mass production is that the craftsmanship is in the workbench itself, not the training of the worker; rather than having a skilled worker measure every dimension of each part of the product against the plans or the other parts as it is being formed, there are jigs and gauge blocks that are ready at hand to ensure that the part is made to fit this set-up. It has already been checked that the finished part will be to specifications to fit all the other finished parts - and it will be made quicker, with no time spent on finishing the parts to fit one another. This is the specialized capital required for mass production; each workbench is different and each set of tools at each workbench limited to those necessary to make one part.

Use of assembly lines in mass production

27

Mass production systems are usually organized into assembly lines. The assemblies pass by on a conveyor, or if they are heavy, hung from an overhead monorail.

In a factory for a complex product, rather than one assembly line, there may be many auxiliary assembly lines feeding sub-assemblies (i.e. car engines or seats) to a backbone "main" assembly line. A diagram of a typical mass-production factory looks more like the skeleton of a fish than a single line.

This is also used in food manufacturer to produce foods continuously.

Characteristics of mass & flow production

(A) Special purpose machines and product type layout:

Special purpose machines are used and the plant assembly stages are laid out on the basis of product layout, the layout-by-sequence.

(B) Lesser flexibility in production schedules

Interruptions due to breakdowns and absenteeism seriously affect production as stoppage of one machine usually disturbs the working of other machines. Systematic maintenance and “provisioning of stand-by operators” are, therefore, two major management functions.

Importance of Job production: -

(A) Continuous flow of material

The flow of materials is continuous and there is little or no queuing at any stage of processing.

(B) Mechanized materials handling

Materials handling is comparatively less firstly because materials move through a short distance between stages and secondly the materials handling activity is mostly mechanized by conveyors and transfer machines.

(C) Low skilled labor

Relatively low skilled labor is employed.

(D) Short manufacturing cycle time

28

The manufacturing cycle time is very short. The machine capacities are balanced by duplicating machines wherever necessary.

(E) Easy supervision

Supervision is relatively easier as only few instructions are necessary and that too at the start of the job.

(F) Limited work- in- progress

Work-in-progress is comparatively less since the manufacturing line is balanced.

EXAMPLE OF MASS PRODUCTION SYSTEM

Flow production involves a continuous movement of items through the production process. This means that when one task is finished the next task must start immediately. Therefore, the time taken on each task must be the same.

Flow production (often known as mass production) involves the use of production lines such as in a car manufacturer where doors, engines, bonnets and wheels are added to a chassis as it moves along the assembly line. It is appropriate when firms are looking to produce a high volume of similar items. Some of the big brand names that have consistently high demand are most suitable for this type of production:

Heinz baked beans

Kellogg’s corn flakes

Mars Bars

Ford cars

ADVANTAGES

Flow production is capital intensive. This means it uses a high proportion of machinery in relation to workers, as is the case on an assembly line. The advantage of this is that a high number of products can roll off assembly lines at very low cost. This is because production can continue at night and over weekends and also firms can benefit from economies of scale, which should lower the cost per unit of production.

DISADVANTAGES

29

The main disadvantage is that with so much machinery it is very difficult to alter the production process. This makes production inflexible and means that all products have to be very similar or standardized and cannot be tailored to individual tastes. However some “variety” can be achieved by applying different finishes decorations etc at the end of the production line.

PROCESS 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. Typical examples of such plants are sugar, steel, cement, paper, coke, refineries, etc.

Characteristics of process production: -

(A) Special purpose machines with built-in controls

The layout of plant, shape and size of its buildings, location of services and storage yards, position of cranes and conveyors is such that material flow is unidirectional and at the steady rate. Special purpose machinery and equipment with built-in controls to measure output and regulate input are employed to suit the needs.

(B) Highly mechanized materials handling

Materials handling is highly mechanized. Conveyor system and automatic transfer machines move materials from one stage to another.

30

JUST-IN-TIME PRODUCTION SYSTEM

(JIT)

Introduction: Just in Time manufacturing is a systems approach to developing and operating a manufacturing system. It is based on the total elimination of waste. JIT is not a new concept. It has been part and parcel of the Japanese manufacturing industry adopted approach for quite some time. It requires that equipment, resources and labor are made available only in the amount required and at the time required to do the job. It is based on producing only the necessary units in the necessary quantities at the necessary time by bringing production rates exactly in line with market demand. In short, JIT means making what the market wants, when it wants it. JIT has been found to be so effective that it increases productivity, work performance and product quality, while saving costs.

Critical Elements in JIT manufacturing

PartnershipsCommitmentsContracts Supporting PartnershipsDeveloping JIT SuppliersPartnerships - A Mutually Beneficial SystemCustomer-Supplier proximity

Partnerships

In the past companies were capable of remaining independent and competitive when they had the capability and resources necessary to produce a product. This is no longer possible. As technology increases in complexity, companies overcome capital limitations or labor intensive requirements by becoming dependent on suppliers to provide services. Many services and Original Equipment Manufacturing (OEM) suppliers have evolved as the result. Companies now appreciate that long-term success relies on the quality of the customer-supplier relationship established so that they will

31

develop successful partnerships. Hence, successful partnerships require the development of mutually beneficial programs.

Contracts Supporting Partnerships

By ensuring fair and equitable contracts, many of the problems in developing customer-supplier relationships are overcome by JIT manufacturers. The goal of JIT is to make long-term contracts with suppliers. Long-term contracts usually extend for one or more years and can consist of one or more part requirements

Integrated Process Control (IPC)In most cases, the typical goals of manufacturing consist of meeting production schedules, cost projections, and product specifications. However, two key points are usually overlooked: optimizing the production process and meeting customer requirements concurrently. The company must be aware of changes in requirements and continually improve the production process. Integrated Process Control (IPC) achieves the goals of JIT manufacturing by optimizing production to meet both manufacturer and customer requirements. In IPC, two concepts control the process of continual improvement.

Goals

Secure a steady flow of quality parts.Reduce the lead time required for ordering product.Reduce the amount of inventory in the supply and production pipe lines.Reduce the cost of purchased material.

ObjectivesImprove purchasing efficiency.Improve quality and delivery performance of suppliers.Isolate factors that influence the cost of material.Remove unnecessary cost factors in the materials supply system.

Tactics

32

Regard suppliers as an extension of the internal manufacturing process and cultivate them as long term business partners.Establish long term purchasing and supply commitments.Improve communication with suppliers.Involve suppliers in early stages of new product planning.Use supplier expertise to improve design manufacturability and reduce product cost.

Quality for JITQuality is an integral part of a JIT program. Quality control concentrates on quality at every stage of manufacture including the purchase of raw material. To increase the supplier quality two methods are used in a JIT system; supplier quality engineering (SQE) and receiving inspection (RI).Supplier quality engineering is used to evaluate supplier capability, help suppliers develop process control, resolve quality issues with suppliers, and certify that suppliers qualify for JIT production. Receiving inspection provides an inspection service for purchasing.

Planning the production process

A valuable tool in planning the production process is to isolate and define the elements that make up a production system as building blocks.

Performance measures

To achieve continued improvement, a company must measure the performance levels of its smallest processes against its optimum values. This is accomplished by having performance measures visible to all levels in a company. The use of control charts is one of the best ways to show the collected performance measures.

ConclusionHence we can see that to have a Total JIT manufacturing system, a company-wide commitment, proper materials, quality, people and equipments must always be made available when needed. In addition; the policies and procedures developed for an internal JIT structure should also be extended into the company's supplier and customer base to establish the identification of duplication of effort and performance feedback review to continuously reduced wastage and improve quality. In general, it can be said

33

that there is no such thing as a KEY in achieving a JIT success; only a LADDER; where a series of continuous steps of dedication in doing the job right every time is all it takes.

34