Manufacturing Systems- Lesson 2

8/3/2019 Manufacturing Systems- Lesson 2

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Manufacturing Systems

Selection of Manufacturing Systems

It must be able to meet thespecifications set for the final product

It must be cost effective

Created by: Atanu Mandal


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The product specifications can be met using

the right technology, but that is always notthe case.

Since stricter specifications add to the costof the product, there is always a trade off

between the desired specifications and thecost to achieve such specifications.



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Factors affecting the choice of ManufacturingSystems

Effect of Volume/ Variety

Capacity of the plant

Flexibility

Lead time

Efficiency

Environment



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One of the major consideration in the processselection is the Volume Variety of the product(s).

i.e. number of products vs. variety



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High Product Variety needs

Highly skilled labour

General purpose machines

Detailed and sophisticated production planningand control systems



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Low Product Variety needs

Low skilled labour

Highly automated mass production systems withspecial purpose machines

Simple production planning and control systems



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Capacity of the Plant

The decision depends on

Projected Sales volume

This decides whether the production processshould be intermittent or continuous.



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Capacity of the Plant

Fixed costs are high for continuous processand low for intermittent process while variablecosts are more for the intermittent process andless for continuous process.

Intermittent process therefore will be cheaperto install and operate at low volumes andcontinuous process will be economical to useat high volume.



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Flexibility

Flexibility implies the ability of the company to satisfy

varied customers requirements. Flexibility andproduct variety are inter-related. If more variety is tobe manufactured, the manufacturing facilities willhave to be commonised (generalised) and dependingupon the volume, the extent of commonalities willrequire to be justified.

Greater commonalities demands intermittentmanufacturing which is associated with higherinventories, large manufacturing lead times andelaborate planning and control.



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Lead Time

Lead times more appropriately called delivery lead

times expected by the customers (i.e. how soon thedemand has to be met without losing on sales) isanother major influencing factor in a competitivemarket. As a general rule, faster deliveries areexpected in a competitive market.

The product, therefore, may require to be produced tostock using principles of batch production/massproduction.



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Efficiency

Efficiency measures the speed and the cost of the

transformation process. Efficiency is greatest whenthe product is mass produced.

But to mass produce a product, greater salesvolumes are required.

Therefore, depending upon the sales volume, product

variety will have to be considered and the processwhich will give the best efficiency in terms of machineand manpower utilization will have to be selected.



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Environment

Environment brings in new technologies and forces the

adoption of new process of manufacturing.

For example, wooden furniture is gradually being replacedby metals and plastic. So a furniture manufacturing unit willhave to change its technology

(i.e. change from one off production to batch production)

to fall in line with changing times. Similarly, as marketpreferences change due fashions or other reasons, themanufacturing process has to be changed accordingly.



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Types of ManufacturingSystems

Project Production Jobbing Production

Batch Production Mass & Flow Production



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Types of Manufacturing Systems

Project Production

A single assignment of complex nature isundertaken for completion in a givenperiod within the estimated expenditure.



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Jobbing Production

One or few units of a product isproduced as per the customersspecification in a given time and cost.



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Batch Production

Limited quantity of multiple productsare produced but only one product ata time.



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Mass & Flow Production

Production run is conducted on one ormultiple machines, arranged in thesequence of production operation and highvolumes of the product are produced at atime and stocked in warehouses, awaitingsale.



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Process Production

Production run is continued for anindefinite period.



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Type of Production

IntermittentProduction

ProjectProduction

JobbingProduction

BatchProduction

ContinuousProduction

Mass & FlowProduction

ProcessProduction


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Project ProductionCharacteristics

Definite beginning and definite endNon-uniform requirement of resources Involvement of different agencies Fixed Position LayoutHigh cost overruns Personnel problems Scheduling and control



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Project Production

Characteristics

Definite beginning and definite end

Each project has a fixed timeline

for execution.



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Non-uniformrequirement of resourcesRequirement for resources in a project is non-uniform.Generally at the completion of a project, the resources areredeployed elsewhere.

Even during the life of the project, the resource requirement isnot uniform.

Generally, at the beginning of a project, the resource reqs. arelow, which builds up as the project progresses and once againthe requirement goes down when the project faces completion.


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Involvement of different agencies

A project generally involves many tasks, each having aspecialty and that calls for the involvement of multipleagencies.

The tasks follow a strict precedence.

As a result of that, co-ordination between the agencies are ofutmost importance.


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Fixed Position Layout

Where the output of a project is a customized product, suchkind of operations are complex and are generallycharacterised byimmobilityduring transformation. Such types of operationsare carried out in Fixed Position assembly type layout. This

can be observed in production of Ship, locomotive, buildingsetc.


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High cost over runs

Often delays take place in the completion of the projects. Suchdelays are generally expensive due to escalation of the costfactors and also penalties.


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Personnel Problems

Project production has various personnel related problems.

When there is a fast buildup, staff is either borrowed fromother departments or hired for short duration. Therefore,personnel involved in the project have limited interest in the

project.Since each project ha limited duration, the staff starts gettingprepared for the next project before the completion of theongoing project.Site of the project may be in an underdeveloped region,thereby causing personnel related problems.


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Scheduling & Control

Due to the large number of activities, involvement of differentagencies and strict precedence requirements, scheduling andcontrol assumes acute importance.

Some network planning techniques like PERT and CPM

proves to be quite useful for the said type of production.

Manufacturing Systems- Lesson 2

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