cad & cag revision

8/7/2019 CAD & CAG revision

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Graphic CommunicationGraphic Communication

CAD/CAG Revision


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ComputerComputer HardwareHardware

Processor

Input Devices

Output Devices Storage Devices


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CPUCPU

Central Processing UnitCentral Processing Unit

The computers Brain

A large micro chip

that controls thecomputerand carries

out all the instructions

and datahandling


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Computer HardwareComputer Hardware

Input Devices


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Keyboard

Keyboard

Used to input text and

numbers into the

computer

Esc F1 F2 F 3 F4 F5 F6 F7 F8 F9 F10 F11 F12

~

`

!1

@2

$4

%5

^6

&7

*8

(9

)0

+=

#3

Q W E R T Y

A S D F G H

Z X C V B

U I O P

J K L

N M

{[

}]

:;

"'

.

?/

Tab

Shift

Ctrl Alt

CapsLock

Alt Ctrl

Shift

Enter

Backspace I n se rt Hom e Pa geUp

De le te En d PageDown

|\

7 8 9

4 5 6

1 2 3

0 .

NumLock

Home PgUp

End PgDn

Ins Del

Enter

/ *

+

PrintScreen

ScrollLock

PauseScrollLock

CapsLock

NumLock


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Mouse

Mouse

Used to guide a

pointerorcursor

around the screen. Functions are selected

with the aid of the

control buttons

Some mice have a

wheel which is used

forzoom and scrolling


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Tracker BallT

racker Ball This device is very

similarto a mouse.

It is used where thereis little desk space

available fora mouse

The large ball is on the

top of the device and

is rotated using the

palm of the hand

The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.


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JoystickJoystick

Used commonly for

games

Used in manysimulation situations.

E.g. Flight and tank

simulators


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GraphicsT

abletGraphicsT

ablet Used forsketching or

tracing drawings into a

computer Uses a puck ora pen

to detect the exact

position of the cursor

on a drawing etc.


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Digital Stills Camera

Digital Stills Camera

This camera stores the

pictures it takes in

digital form. Thesecan the be downloaded

to a computerfor

inclusion in a DTP

document etc.


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ScannerScanner Used to electronically

convert paperimages

to to computerfiles. Text can be scanned in

usingOCR (Optical

CharacterRecognition)

software

The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.

Flat bed Scanner

Hand held Scanner


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Computer HardwareComputer Hardware

Output Devices


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Flatbed PlotterF

latbed Plotter Only used by CAD

programs

Produces linedrawings

Page size is limited by

size of plotterbed

Not suitable for

printing pictures


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Drum Plotter

Drum Plotter

Drum plotterare

usually used in

industry to producelarge drawings (up to

A0)

Papermoves backand

forwards while penmoves from side to

side


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Fax/

Modem

Fax/

Modem A modem is bothan

input and output

device Data can be exchanged

with drawing offices

across the world

electronically


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StorageD

evicesStorageD

evices

A PC usuallyhas several methods of storing data on it.

These may include a mixture of fixed and removablestorage systems


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Floppy

Disc

Floppy

Disc

Portable removable

storage

Onlyholds 1.44 MBof data

Can be used in most

computersystems

Easily damaged


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HardD

riveHardD

rive Large capacity storage

Not portable build

into base unit ofcomputer

Fast savingand

retrieval of data


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ZipD

iscZ

ipD

isc Similarto floppy disc

but greaterstorage

capacity (100 250MB)

Portable

Not all computers

have Zip drives


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CD

RomCD

Rom High capacity portable

storage

Needs a CD writertostore data


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CAD

CommandsCAD

Commands You must know foryourexam the following

common CAD commands


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CAD Commands 1CAD Commands 1

An on screen grid which

can be set to any size.

Can make it easierto do

orthographic drawings

An on screen grid which

is set at 30 deg. Can

make it easierto do

Isometric drawings


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This restricts the start

and end points of lines

to a predefined grid

This allows different

types of information to

be keep separate on a

drawing


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Allows a userto

increase ordecrease the

screen view so that they

can see more detail

Allows the drawing of

rectangularshapes on

screen


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Allows the userto draw

arcs and circles on

screen

Allows the userto copy

and position objects or

parts ofa drawing without

having to redraw them


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This allows the userto draw

circularorrectangular

arrangements from a single

object

Fillet puts aradius on a

corner(rounded)

Chamfer puts a 45 deg

angle on a corner


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Trim/Breakremoves an

unwanted section of line,etc.

Extend makes a line, etc.

longer(usually to meet

anoth

erobject)

This allows the userto

turn an object at anyangle about a point


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This allows the usertochange the size ofan

object

This flips an object about thehorizontal orvertical axis


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Storage and retrieval

A completed drawing or series of drawings can be stored on hard drive, floppy disc, Zip discor CD-R. These formats require less storage space than paper drawings. The drawings canthen be printed as many times as required with no deterioration in quality.

Ease of modification

Companies who use CAG systems have advantages over competitors who rely on moretraditional methods of modifying drawings. The ease and speed with which modificationscan be made reduce time and costs, which in turn increases productivity.

Repetitive elements (library)

Drawings can contain a number of repetitive elements such as doors, windows, kitchenfittings and appliances. It is useful to have these items stored in a CAD library file. CADlibrary files are available for mechanical engineering, architecture and electronics. Items thatyou design need only be drawn once, saved to a library file, then retrieved and positionedeach time they are required on a drawing. This saves time and effort, which increasesproductivity.

ADVANTAGES OF A CAG SYSTEMOVER A DRAWING BOARD 1


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ADVANTAGES OF A CAG SYSTEMOVER A DRAWING BOARD 2

Drawing speed

It does take a considerable amount of time and financial investment by companies to train their

CAG operators. In relative terms, however, drawing production is much faster using CAG thanusing traditional methods, so the company will save time and money in the long run.

Standardisation of drawings

Standardisation of drawings is often determined by drawing standards such as 851.

Standardisation of drawing layouts and styles can easily be created in the 'in-house' orcorporate style adopted by the operator or the company.

Drawing size and flexibility

Drawings can be enlarged or reduced with no loss of detail. Extremely fine, detailed work can

be produced using commands such as ZOOM. Positive location tools such as GRID, GRID

SNAP and ATTACH enable accuracy to be maintained even in the smallest details.

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