Process selection

PROCESS SELECTIONPROCESS SELECTION

Chapter 4Chapter 4

INTRODUCTION to Operation Management 4e, Schroeder

Copyright © 2008 by The McGraw-Hill Companies, Inc., All Rights Reserved.

McGraw-Hill/Irwin

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Product-Flow CharacteristicsProduct-Flow Characteristics

Types of Product FlowTypes of Product Flow– Continuous processContinuous process– Job shopJob shop– Assembly LineAssembly Line– BatchBatch– ProjectProject

Continuous Process Continuous Process

Its name derives from how materials move Its name derives from how materials move through the process. Usually one primary through the process. Usually one primary material, such as a liquid, gas, wood fibers, or material, such as a liquid, gas, wood fibers, or powder, moves without stopping through the powder, moves without stopping through the facility.facility.

Example: Oil refineryExample: Oil refinery

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Product-Flow CharacteristicsProduct-Flow CharacteristicsContinuous ProcessContinuous Process

Process industries (beer, paper, oil, Process industries (beer, paper, oil, etcetc.).)

Highly standardized and automatedHighly standardized and automated

High volumes of productionHigh volumes of production

Flexibility limitedFlexibility limited

Assembly Line FlowAssembly Line Flow

Materials move linearly from one operation to Materials move linearly from one operation to the next according to a fixed sequence, with the next according to a fixed sequence, with little inventory held between operations. little inventory held between operations.

Each operation performs the same process over Each operation performs the same process over and over with little variability in the products or and over with little variability in the products or services provided. Production orders aren't services provided. Production orders aren't directly linked to customer orders, as is the case directly linked to customer orders, as is the case with project and job processes.with project and job processes.

Example: Automobile production lineExample: Automobile production line

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Assembly Line FlowAssembly Line Flow

Manufacturers with line flow processes often Manufacturers with line flow processes often follow a make-to-stock strategy, with standard follow a make-to-stock strategy, with standard products held in inventory so that they are products held in inventory so that they are ready when a customer places an order. This ready when a customer places an order. This use of a line flow process is sometimes called use of a line flow process is sometimes called mass production.mass production.

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Product-Flow CharacteristicsProduct-Flow CharacteristicsAssembly Line FlowAssembly Line Flow

Linear sequence of operationsLinear sequence of operations

Discrete products (autos, appliances, Discrete products (autos, appliances, etcetc.).)

High-volume, standardized productsHigh-volume, standardized products

Inflexibility in product and volumeInflexibility in product and volume

Very efficientVery efficient

Large capital investmentLarge capital investment

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Assembly Line FlowAssembly Line Flow(metal bracket, see fig. 4.1)(metal bracket, see fig. 4.1)

paintdrill bend

Task or work station

Product flow

cut

Batch ProcessBatch Process

A A batch processbatch process is similar to a job shop, is similar to a job shop, except that the sequence of activities tends to except that the sequence of activities tends to be in a line and is less flexible.be in a line and is less flexible.

Products are produced in batches, for example, Products are produced in batches, for example, to fill specific customer orders.to fill specific customer orders.

Example: BakeryExample: Bakery

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Batch ProcessBatch Process

A batch of one product or customer group is A batch of one product or customer group is processed, and then production is switched to processed, and then production is switched to the next one. the next one.

Eventually, the first product or service is Eventually, the first product or service is produced again.produced again.

A A batch processbatch process is similar to a job shop, is similar to a job shop, except that the sequence of activities tends to except that the sequence of activities tends to be in a line and is less flexible. The activities, be in a line and is less flexible. The activities, while in-line, are disconnected from one while in-line, are disconnected from one another.another. 4-4-1010

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Product-Flow CharacteristicsProduct-Flow CharacteristicsBatch FlowBatch Flow

Production of batches or lotsProduction of batches or lots

Batches flow from one work center to anotherBatches flow from one work center to another

Low volume productsLow volume products

Many different types of productsMany different types of products

Flow is jumbled and intermittentFlow is jumbled and intermittent

Flexible labor and equipmentFlexible labor and equipment

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Batch FlowBatch Flow (three metal brackets, see fig. 4.2)(three metal brackets, see fig. 4.2)

Cut Paint

Task or work station Product flows

Bend

Drill

Batch ABatch BBatch C

Job ShopJob Shop

A A job shopjob shop is a flexible operation that has is a flexible operation that has several activities through which work can several activities through which work can pass. In a job shop, it is not necessary for all pass. In a job shop, it is not necessary for all activities to be performed on all products, and activities to be performed on all products, and their sequence may be different for different their sequence may be different for different products.products.

Example: Printing and Machine shopExample: Printing and Machine shop

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Job Shop, continuedJob Shop, continued

To illustrate the concept of a job shop, To illustrate the concept of a job shop, consider the case of a machine shop. In a consider the case of a machine shop. In a machine shop, a variety of equipment such as machine shop, a variety of equipment such as drill presses, lathes, and milling machines is drill presses, lathes, and milling machines is arranged in stations. Work is passed only to arranged in stations. Work is passed only to those machines required by it, and in the those machines required by it, and in the sequence required by it. This is a very flexible sequence required by it. This is a very flexible arrangement that can be used for wide variety arrangement that can be used for wide variety of products.of products.

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Job Shop, continuedJob Shop, continued

Companies choosing a job process often bid Companies choosing a job process often bid for work. Typically, they make products to for work. Typically, they make products to order and don't produce them ahead of time. order and don't produce them ahead of time. The specific needs of the next customer are The specific needs of the next customer are unknown, and the timing of repeat orders from unknown, and the timing of repeat orders from the same customer is unpredictable. Each new the same customer is unpredictable. Each new order is handled as a single unit--as a job.order is handled as a single unit--as a job.

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ProjectProject

In a In a projectproject, the inputs are brought to the project , the inputs are brought to the project location as they are needed; there is no flow in location as they are needed; there is no flow in the process.the process.

The firm brings together the resources as The firm brings together the resources as needed, coordinating them using project needed, coordinating them using project management techniques.management techniques.

Since there is no flow of product - the quantity Since there is no flow of product - the quantity produced usually is equal to one.produced usually is equal to one.

Example: building constructionExample: building construction4-4-1616

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Factors Affecting Process ChoiceFactors Affecting Process Choice

Market conditions and competitionMarket conditions and competition

Capital requirementsCapital requirements

Labor supply and costLabor supply and cost

State of technologyState of technology

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PRODUCT-PROCESS MATRIX (Figure 4.5)

Low volume, low standardization

Printing

HeavyEquipment

Autoassembly

SugarRefinery

Low volume,Multiple products

Higher volumefew major products

High volume, highstandardization,commodity

Job Shop

Batch

Assemblyline

Continuous NONE

NONE

Unique, one ofa kind product

ProjectBuilding