production management- types of process

CHAPTER

Process Selection and Process Selection and Methods

TYPES OF PROCESS

Conversion processes : converts input into value added outputs outputs

E.g. : iron ore is converted into steel

•Fabrication Processes : change input into a specific form e.g. sheet metal is turned into the car door etc

Assembly processes : putting things together . E.g. fixing a pilfer cap on a liquid medicine bottle or fixing door to body of car .

EFFICIENCY

Any production method relies on efficiency – this can be viewed in different ways:

Productivity – a measurement of output per unit of the factor used (labour, capital or land)

Total OutputTotal Output

Productivity = -------------------

Units of Factor

Technical Efficiency – output produced using the fewest possible inputs

Productive Efficiency – output produced at the lowest possible cost

PRODUCTION METHODS

Agriculture tends to be very land intensive –efficiency could efficiency could be measured in terms of output per acre/hectare

PRODUCTION METHODS

As technology and analysis of production methodology has improved, methods have changed have changed dramatically –what used to be labour intensive production methods are now capital intensive

PRODUCTION METHODS

The choice of production method and the factor inputs depends on such things as:

• the nature of the product

• factor costs

• the scale of production

PRODUCTION DECISIONS

Market size and Segment

Which method? Type of ProductComplexity of design

Factor Costs –Land, Labour and

Capital

TYPES OF OPERATIONS

INCREASED VOLUME

Project/Job Shop

Unit or Batch Mass/

Assembly

Continuous

PROCESS DESIGN

� Project Processes (Fixed Position)

� Intermittent Flow Processes (Batch Shops)

� Continuous Flow Processes (Flow Shops)

� Processing Industries (Continuous)

JOB SHOP (FIXED POSITION)

� People and material move

� Have limited duration

� Small scale

� Examples

� Housing� Housing

� Ship building

� Dam

� Appliance Repair

INTERMITTENT FLOW PROCESSES

(BATCH SHOPS)

�No pattern exists between process of different products

�Appropriate to service organizations

�Moderate volume

Example:�Example:� Machine Shops

� Auto Repair Shops

� Commercial Bakery

� Classroom Lecture

CONTINUOUS FLOW PROCESSES

(FLOW SHOPS)

� Sequences are the same (Standard Routes)

� High volumes of standardized goods or services

� Examples:

� Assembly Lines

� Car Wash� Car Wash

PROCESSING INDUSTRIES

(CONTINUOUS FLOW)

� One primary input (gas, wheat, etc) is converted to multiple outputs

� Very high volumes of non-discrete goods

� Example:

� Petroleum� Petroleum

� Chemicals

� Food Industries

PROCESS CHARACTERISTICS

Characteristics Project Intermittent Continuous

PRODUCTPRODUCT

Order Type Single Unit BatchContinuous or large batch

Flow of Product None Jumbled Sequence

Product Variety Very High High Low

Market type Unique Custom Mass

Volume Single Unit Medium High

PROCESS CHARACTERISTICS

Characteristics Project Intermittent Continuous

CAPITAL

Inventory Medium High LowInventory Medium High Low

EquipmentGeneral

Purpose

General

Purpose

Special

Purpose

LABOR

Skills High High Low

Task Type Non-routine Non-routine Repetitive

PROCESS CHARACTERISTICS

Characteristics Project Intermittent Continuous

CONTROLCONTROL

Production Difficult Difficult Easy

Quality Difficult Difficult Easy

Inventory Difficult Difficult Easy

EQUIPMENTGeneral

Purpose

General

Purpose

Special

Purpose

AUTOMATION

� Automation: Machinery that has sensing and control

devices that enables it to operate

� Fixed automation

� Programmable automation

• Computer-aided design and manufacturing systems (CAD/CAM)

• Numerically controlled (NC) machines

AUTOMATION

• Numerically controlled (NC) machines

• Robot

• Manufacturing cell

• Flexible manufacturing systems(FMS)

• Computer-integrated manufacturing (CIM)

FUNCTIONAL AREAS BEING

LINKED TO MANAGE THE FLOW OF

INFORMATION

� Design

� Handling of Materials

Storage and Retrieval of Information� Storage and Retrieval of Information

� Control of Machine Tools

DESIGN

�CAD� No longer limited to the top, side and front views

� Can observe the rotation of the part about any axis on the

screen

� Generally, improves productivity in the drafting room by a

factor of 3 or morefactor of 3 or more

� At GM, the redesign of a single auto model requires 14 months

instead of 24 months

� The time needed to design custom values reduced from six

months to one

HANDLING OF MATERIALS

� Data processing technology can be applied to the

control of 3 general kids of machines in the

factory:

� Machines that store, retrieve, or transport materials

� Machines that process the materials� Machines that process the materials

� Robots

HANDLING OF MATERIALS

� Automatic storage and retrieval systems transfer

pallets of material into or out of storage rack up

to 100 feet high

� Mini Loaders

� Hold drawers of small parts� Hold drawers of small parts

� Automatic Warehouse

� Automatic shuttle takes the place of the fork-lift truck and

its human operations

STORAGE AND RETRIEVAL

OF INFORMATION

�GT

� The formation of part families based on design

or manufacturing similarities (or both)

� Classification of parts speed up the design of

similar parts in the companysimilar parts in the company

� Only 20% of the parts actually need new

design. 40% could be built from an existing

design and the other 40% could be created by

modifying an existing design.

� Automatic guided vehicle

CONTROL OF MACHINE TOOLS

� NC

� Machine tools run by programs

� DNC

� Direct numerically controlled machine tools

� Several computerized, NC machine tools are linked � Several computerized, NC machine tools are linked

by a hierarchy of computers

CONTROL OF MACHINE TOOLS

�FMS

�Flexible Manufacturing System

� It consists of an integrated collection of:

� Automated Production Processes� Automated Production Processes

�NC

�Robots

� A material transport system

�An automated transfer line

�Robots