Various Types & Importance of Production Systems

7/28/2019 Various Types & Importance of Production Systems

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PROJECT REPORT

ON

IMPORTANCE OF

PRODUCTION SYSTEMS

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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

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INTRODUCTION

Production is a conversion function by which goods and services areproduced. 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.

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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 externalenvironment. 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.

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FACTORS INFLUENCING CHOICE OFMANUFACTURING 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 specificationsand 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.

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Relationship between degree of repetitiveness & transformation Process

High product variety require highly skilled labour, general purposemachines, 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 reallysmall. 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

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(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 forcontinuous 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 customersrequirements. 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.

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(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.

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CLASSIFICATION OFMANUFACTURING 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 flexible enough to handle a wide variety of products and sizes.

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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.

(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.

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(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 regulatethe 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 estimatedexpenditure.

(b) Job production

Jobbing production where one or few units of a product are produced to

customers 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 ofprocesses can be adopted. Due to this routing and scheduling for the whole

process can be standardized.

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

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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 routesheets 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. Continuoussystem can be divided into two types of production, namely

(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

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sequence of operations and several number of a product are manufactured at

a time and stocked in warehouse awaiting sales.

INTERMITTENT PRODUCTIONSYSTEM

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 Production : -

(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

can be observed in production of ships, locomotive, aircraft, construction of

roads/ buildings, etc.

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(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 moretime 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 Production: -

(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 agenciesA project generally involves many tasks, each having its own specialization

to be performed by different agencies. The tasks generally have strict

precedence (i.e. certain tasks must be completed before the next begins)

amid as such co-ordination between agencies is of utmost importance.

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(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

customers specifications, within, the given period and wit/tin the price

fixed prior to tile contract. Some typical examples of industries engaged injobbing 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.

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(B) Large work-in-progress

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 andmachines 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 batchor 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 production: -

(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 materialsThe 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

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Plant and equipment is designed or procured and arranged to obtain

maximum flexibility. General purpose machines and handling equipments

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 operators 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 labourThe 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 asupervisor - 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.

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(G) Decentralized Process

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 theindividual 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)

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ADVANTAGES

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 aunique 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 themanufacture 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.

Batchproduction 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 willfit 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.

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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

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 canpredict 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 ofgear 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

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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

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.

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Expediting is generally necessary since quite often jobs, due to imbalances

in work content, tend to lag behind.


(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 thoseinvolving 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 SYSTEM

As 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.

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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

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

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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

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

damage to stock.

CONTINUOUS PRODUCTIONSYSTEM

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

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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

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 formass 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 migr engineer Marc Brunel, while working for the

British Admiralty in the Portsmouth Dockyard, devised a process forproducing 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

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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 tracedto 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

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 massproduction transformed the organization of work in three important ways.

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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.

In the 1970s and '80s some countries, particularly in Asia and South

America, that had hitherto been largely agricultural and that had importedmanufactured 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 isdecreased. 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.

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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

Mass production systems are usually organized into assembly lines. The

assemblies pass by on a conveyor, or if they are heavy, hung from anoverhead 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.


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(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

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 similaritems. Some of the big brand names that have consistently high demand are

most suitable for this type of production:

Heinz baked beans

Kelloggs corn flakes

Mars Bars

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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

The main disadvantage is that with so much machinery it is very difficult to

alter the production process. This makes production inflexible and meansthat 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 insuch 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.

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(B) Highly mechanized materials handling

Materials handling is highly mechanized. Conveyor system and automatic

transfer machines move materials from one stage to another.

JUST-IN-TIME PRODUCTION SYSTEM

(JIT)

Introduction: Just in Time manufacturing is a systems approach todeveloping 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 ofthe 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

Partnerships

Commitments

Contracts Supporting Partnerships

Developing JIT Suppliers

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Partnerships - A Mutually Beneficial System

Customer-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

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 canconsist 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 JITmanufacturing by optimizing production to meet both manufacturer and

customer requirements. In IPC, two concepts control the process of

continual improvement.

Goals

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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.

Objectives

Improve 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

Regard suppliers as an extension of the internal manufacturing process andcultivate 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 JIT

Quality is an integral part of a JIT program. Quality control concentrates onquality 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.

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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 acompany. The use of control charts is one of the best ways to show the

collected performance measures.

Conclusion

Hence 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 tocontinuously reduced wastage and improve quality. In general, it can be said

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.

Documents

Various Types & Importance of Production Systems