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GET130: Intro to Engineering Technology Fall 2016 Design Representation 1 GET130 Intro to Engineering Technology Fall 2016 Once a design is conceptualized, it must be represented and communicated to others in a complete and technically accurate fashion. Communication methods: oral presentations written documents technical drawings demonstration of model / prototype Different engineering fields use different types of representations and symbology. and tools (software packages) to work with them symbology, def: a system of symbols † www.merriam-webster.com 2 sketch: generally refers to a freehand drawing including artistic implications subjective/ambiguous impressions like you did in the problem solving lab drawing: result of using drawing instruments or technology ruler/compass drafting board computer with CADD software CADD: Computer Aided Design and Drafting 3 civil grading, landscaping, etc. topological & relief maps architectural plan, section, elevation, perspective http://blog.visual.ly/visualization-in-architecture-drawing-types/ construction electrical, mechanical (HVAC), plumbing patent http://www.uspto.gov/patents/ General Info Drawing Standards engineering clearly defines requirements for engineered items… 4 block diagram computer/software engineering: flowchart electrical engineering: schematic mechanical: layout part/detail assembly / exploded view arrangement bill of materials (BOM) 5 high-level presentation of a system to show overall concepts without implementation details aka system diagram used in all engineering fields symbology: blocks – denote principle parts or functions of the system lines – show relationships between the blocks 6
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Page 1: GET130: Engineering Technology Fall 2016jsumey/CET490/N08-DesignRepresentation.pdfGET130: Intro to Engineering Technology Fall 2016 Design Representation 1 GET130 Intro to Engineering

GET130: Intro to Engineering Technology Fall 2016

Design Representation 1

GET130 Intro to Engineering TechnologyFall 2016

Once a design is conceptualized, it must be representedand communicated to others in a complete and technically accurate fashion.

Communication methods:• oral presentations• written documents• technical drawings• demonstration of model / prototype

Different engineering fields use different types of representations and symbology.• and tools (software packages) to work with them

symbology, def: a system of symbols†

† www.merriam-webster.com2

sketch: generally refers to a freehand drawing• including artistic implications

• subjective/ambiguous impressions• like you did in the problem solving lab

drawing: result of using drawing instruments or technology• ruler/compass• drafting board• computer with CADD software

CADD: Computer Aided Design and Drafting

3

civil• grading, landscaping, etc.• topological & relief maps

architectural• plan, section, elevation, perspective• http://blog.visual.ly/visualization-in-architecture-drawing-types/

construction• electrical, mechanical (HVAC), plumbing

patent• http://www.uspto.gov/patents/ General Info Drawing Standards

engineering• clearly defines requirements for engineered items…

4

block diagram computer/software engineering:

• flowchart electrical engineering:

• schematic mechanical:

• layout• part/detail• assembly / exploded view• arrangement

bill of materials (BOM)

5

high-level presentation of a system to show overall concepts without implementation details• aka system diagram• used in all engineering fields

symbology:• blocks – denote principle parts or functions of the system• lines – show relationships between the blocks

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 2

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a visual diagram tool that shows the sequencing of a process or algorithm to solve a specified problem

typically used to design/document/analyze computer programs, program flowchart

symbology:• blocks – describe the steps to be performed• lines – show the order of the process

how it works…

9 10

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Alternate process(entry)

Process

Predefined process(subroutine)

On-page connector

Off-page connector

Decision

Data input/output

Terminator

• a good (free) diagramming tool: Diagram Designer

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 3

Scenario:

You jump in your car, hit the key, but your car won’t start.

What to do?

13 14

car won't start

willkey turn

?

put car in park

doesengine crank

?check battery

batterygood

?

NN

N

N

Y

Y

replace battery

gotgas?

get gas!N

is carin park

?

Y

Y

Y

callservice

technician

carstart now

?

done,be happy

Y

N

done,pay da man

A

A

from the flowchart given, determine the output of x, y, and i

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START

i=0x=10y=1

x > y?

x=x/y

y=y+i

i=i+1

Outputi,x,y STOP

N

Y

x y ix y i10 1 0x y i

10 1 010 1 1

x y i10 1 010 1 110 2 2

x y i10 1 010 1 110 2 25 4 3

x y i10 1 010 1 110 2 25 4 3

1.25 7 4

an abstract representation of a system using an appropriate symbology

heavily used in electronics (but not only!)• aka circuit diagram

Electronic Design Automation (EDA) computer tools provide for schematic capture and editing◦ ex: National Insruments’ Multisim

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audio power meter:

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7-segment display†:

† this schematic done in Multisim

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 4

a really nice table of electrical and electronic symbols may be found at RapidTables.com• http://www.rapidtables.com/electric/electrical_symbols.htm

they also have another table of some electronic components with photos!• http://www.rapidtables.com/electric/Electronic_components.htm

another library of 800+ electronic symbols & photos:• http://www.electronic-symbols.com/

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include:

are drawn in conformance to industry standards• ex: ASME Y14.24 drawing standards Table of Contents

• required by Department of Defense (DoD) policies

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• layout • modify• detail • control• assembly • interface• installation • mechanical schematic• arrangement • electrical schematic

shows design requirements of major system components via pictorial, notational, and dimensional data

used during development to prepare other engineering drawings

not typically used for fabrication

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click drawing to open PDF

provides complete definition of the part or parts shown including dimensioning and tolerances, also identifies the parts

includes materials and fabrication info

may be either for a single part (monodetaildrawing) or multiple parts (multidetail)

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 5

Notice: dimensioning tolerances title block identification

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shows how individual parts fit together to form an assembly

may be in the form of an exploded view

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depicts the physical relationship of significant components using appropriate projections or perspective views

may include reference dimensions, but not item identification info

used to convey general description of the configuration and location of significant items, i.e. ancillary info

not normally used to control design

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 6

sank 11/01/1995 off Palungitak Island in northern Newfoundland due to “loss of situational awareness”

3 crew members lost

1 survivor paddled 2 hours to shore

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in technical drawings, various views are used to describe an object or item

these views basically fall into two categories:• Isometric (pictorial)• Orthographic (plan)

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shows 3 surfaces of an object in a 2D fashion

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• perspective view – attempts to replicate what is seen by human eye or camera

• lines of depth converge to one or two vanishing points on an imaginary horizon

• most complex but most accurate

• isometric view – uses only vertical and 30º lines to “simulate” perspective

• easy to create and widely used

• supported by CAD tools

illustrates a 3D object via 2D views of two or more of the object surfaces

“a collection of views of an object formed by projectors onto and perpendicular to the desired plane of projection”• in English please???

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projection onto the frontal plane

projection onto the horizontal plane

projection onto the profile plane

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envision the object contained in a glass box wrapped with paper

each of the 6 sides shows its unique projection

cut & unfold paper into its 2D form

all planes are hinged to the front plane, except for back which is hinged to left side

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 7

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note that rarely do we need all 6 views• 3 views is typical, some objects need only 2• or even 1 as in the previous metal handle

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a system of standard symbology and conventions used on the detail drawing to convey maximal design details while keeping it neat and uncluttered

is a language of communication between designer and fabricator

based on ASME Y14.5 Dimensioning and Tolerancing standard

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essential components needed on every drawing to ensure correct interpretation• standard symbols for particular items• clear lettering (UPPERCASE only)• standard drawing views• clear consistent lines, dimensions & units• appropriate clarification notes• title block: drawing title designer/drawer’s initials & date material & finish specifications allowable tolerances (variations)

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metric dimensions include 0 before decimal point (0.5 mm); inch do not (.25 in)

line types:• extension lines – emanate from object with visible

separation gap• dimension lines – have break for the numbers, 10mm

from the object; 6mm for subsequent lines; shortest closest to object and longer lines further away

• leader lines – indicate surfaces & hole diameters; angled & pointing towards hole center

• hidden (dashed) lines – indicate a feature better seen in another view

• center lines (di-dashed) – indicate a cylinder object

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dimension lines

leader line

hidden line

cylinder line

extension lines

stacked dimensions

tolerance specifications

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GET130: Intro to Engineering Technology Fall 2016

Design Representation 8

refers to allowable variation of a dimension• to accommodate imperfect manufacturing

processes• indicated with ± notation

specify only as tightly as needed• because tighter tolerances result in increased

manufacturing costs• and possibly use of more expensive equipment

tolerances are specified:• with a dimension line,• in a drawing note, or• in the title block as a drawing default

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from the ASME standard grouped by types

• form, profile, orientation, location, runout

ex: a piece thickness spec’d at .500±.003 in• it could vary between .497 - .503

in look for these in CADD

software!

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A bill of materials (BOM) is a list of the raw materials, sub-assemblies, intermediate assemblies, sub-components, parts and the quantities of each needed to manufacture an end product†.

used for communication between manufacturing partners (external BOM), or confined to a single manufacturing plant (internal BOM)

can be used in various contexts:• engineering BOM – design• electronics BOM – circuit board components• sales BOM – ordering/procurement/inventory• service BOM – maintenance

45† http://en.wikipedia.org/wiki/Bill_of_materials

BOMs can be created/maintained with• spreadsheet program (Excel)• purpose-built applications

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Diagram Designer• flowcharts, illustrations• http://logicnet.dk/DiagramDesigner

Autodesk Inventor Dassault Systems SolidWorks National Instruments Multisim◦ circuit schematics and PCB layout

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American Society of Mechanical Engineers (ASME)• https://www.asme.org/

“Engineering drawing”• http://en.wikipedia.org/wiki/Engineering_drawing

Engineering Drawing and Sketching [tutorial]• http://www.me.umn.edu/courses/me2011/handouts/drawing/blanco-tutorial.html

“Engineering Drawing Practices”◦ http://www.dtic.mil/ndia/2008technical/GastonEngineeringDrawingsY14_24a.pdf

“Flowchart”• http://en.wikipedia.org/wiki/Flowchart

GD&T Reference Guide• http://www.jus-rite.com/gdtguide.html

The United States Patent and Trademark Office (USPTO)• http://www.uspto.gov/patents/

Technical Drawing• http://machineshop.olin.edu/resources/documents/Technical%20Drawing%20-

%20Class%20Handout.pdf

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