1.unit 1: general conditions 1)fot review 2)impacts of technology 3)problem solving 4)metrology...
TRANSCRIPT
1. Unit 1: General Conditions1) FOT Review2) Impacts of Technology3) Problem Solving4) Metrology
2. Unit 2: Communication Technology1) History of Communication Technology2) Types of Communication Technology3) Drawing and drawing types
1) Orthographics and Isometrics2) AutoCAD and Google Sketchup
3. Unit 3: Fuels and Engines
SEMESTER 1 EXAMTopics Covered
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BPI-IOT CLASSWORK 5 JAN 11 WETZEL, T. 3
REMINDER Title Blocks
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FOT Review – EngineeringWhat is ENGINEERING?
Systematic application of mathematic, scientific, and technical principles to yield a tangible end product that meets our needs or desires.
What are the key words?1. Systematic application2. Mathematic, Scientific, Technical 3. Principles4. Tangible end product5. Needs or Desires
FOT REVIEW
What is Technology?– The application of knowledge, tools, and skills
to solve problems and extend human capabilities
– Performs tasks by using an artifact that is not part of the human body
Engineering creates Technology
An object made by humans for a specific purpose
FOT REVIEW
Engineering
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Core Technologies
Core Technologies1. Structural2. Optical3. Fluid4. Thermal5. Biotechnology6. Electrical7. Electronic8. Material9. Mechanical
Technology Systems
SOFTBEEMM
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Components:– Goals
• Humans develop technology to meet needs• Each artifact meets more than one goal
– Inputs • Resources that go into a system and are used by it
– Processes• Design Process, Production Process, Mgt. Process
– Outputs• Technological systems are designed to produce specific outputs. • Manufactured products, constructed structures, communicated
messages, transported people or goods.– Feedback and Control
• Using information about the outputs to regulate the system.
Technology as a SystemFOT REVIEW
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INPUTS PROCESSES
OUTPUTS
GOALS
GOALS
FEEDBACKControl
System Components
FOT REVIEW
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INPUTS
• Resources that go into technology:– People – planners, designers, builders, testers,
administration, investors, etc.– Information – math, science, and technical principles, etc.– Capital – $ for employees, materials, marketing, etc.– Time – to plan, design, make, market, ship, etc. – Machines and tools – manufacturing facilities, etc.– Energy – to design, construct, ship, etc.– Materials – natural, synthetic, composite
FOT REVIEW
PICTMEM
1. ModelUsed to communicate design ideas and processes. May be a small, large, or full scale model.
2. PrototypeA working model used to test a design concept by making actual observations and necessary adjustments.
Make Model / Prototype
Outcome: Tangible ObjectIOT
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1. Safety – is the product safe to use/construct?2. Cost – is it affordable?3. Reliability – will it work consistently over time?4. Environmental Concerns – does it harm the natural or
human environment negatively? 5. Ergonomics – how efficiently can the human body utilize
it?6. Manufacturability – can it be made?7. Quality Control – does it meet customer requirements?8. Maintenance – how easily can it be maintained or
upheld?
Constraints on the Engineering Design Process
(A constraint is a limit or restriction)
SCREEMQuM
1. If Technology is…The ability of humans to combine ingenuity and resources to meet needs and wants of people
2. Then Technology Assessment is…The conscience that polices the possible impacts of applying technology
Assessing Technology
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The analysis of technology should be based on facts and research rather than media hype or personal opinion.
1. 2. 3. 4. 5. 6. 7. 8.
Design Process
Define the ProblemBrainstorm, Research, Generate IdeasExplore PossibilitiesDevelop a Design ProposalMake Model/PrototypeTest and Evaluate Refine the DesignCommunicate the Solution
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5 Impacts of Technology
5 Main Areas Impacted by Technology:– Social: How does it affect interdependent human
relationships?– Cultural: How does it affect the characteristic features of
everyday existence?– Economic: How does it affect the production, distribution,
and consumption of goods and services?– Political: How does it affect the government?– Environmental: How does it affect both the human and
natural environments? (aesthetics included here)
SPEEC
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Impacts of Technology
Time Ranges:– Initial Effects– Intermediate Effects– Long-term Effects– Historical Technological Impact– Recommendation
5 Main Areas Impacted by Technology:Social, Cultural, Economic, Political,
Environmental
PROBLEM SOLVING STRATEGIES
- DRAW A DIAGRAM- SOLVE ALGEBRAIC EQUATIONS- MAKE A MODEL- CREATE A FLOWCHART- RUN A SIMULATION- TRIAL AND ERROR
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PROBLEM #1 DIAGRAM SOLUTION:1. Chicken crosses the river.
2. Boat returns to the other side.3. Chicken feed crosses the river.
4. Chicken and boat returns to the other side.5. Fox crosses the river.
6. Boat returns to the other side.7. Chicken crosses the river.
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PROBLEM #2 :
A man lived one-fourth of his life as a boy in Baltimore, one-fifth of his life as a young man in Youngstown, one-third of his life as a man in Manitoba, and the last thirteen years of his life in Thurmont. How old was the man when he died? Write down your answer.
X = X/4 + X/5 + X/3 + 13
60X = 15X + 12X + 20X + 78060X = 47X + 78013X = 780
X = 60 yearsIOT
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PROBLEM #2 ALGEBRAIC SOLUTION:Define the unknowns: X = man’s total age. X/4 = years as a boy X/5 = years as a youth X/3 = years as a manWrite an equation:
Solve the equation:
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PROBLEM #3 :
Given a stack of individual blocks as shown. How many more blocks are needed to fill the empty spaces and form a large cube? Write down your answer.
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PROBLEM #3 MODEL SOLUTION:
8 blocks on level three6 blocks on level two
9 blocks on level four
23 blocks were missing
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PROBLEM #4 : HOMEWORK
Given a stack of individual blocks as shown. If all of the visible blocks were to disappear suddenly, how many blocks would remain? Write down your answer.
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DRILL A: BOWLING PINS - SOLUTION
Ten bowling pins form a triangular arrangement. Move 3 pins so that the resulting triangle points in the opposite direction.
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DRILL B: CROSSING CLOCK HANDS - SOLUTION
On a regular clock, how many times will the minute hand and hour hand cross each other between the hours of 10 a.m. and 2 p.m.?
1. Between 10:54 and 10:55 a.m.2. At 12:00 noon
3. Between 1:05 and 1:06 p.m.
The train traveled 25 mph for one hour to reach the top of the hill. Average speed is equal to total distance divided by total time. 25 miles divided by 1 hour is 25 mph. Therefore, the train traveled 25 miles to reach the top of the hill in 1 hour.
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PROBLEM #2 (AVERAGE SPEED): SOLUTION
The return trip down the hill is also 25 miles. Therefore, the total round-trip will be 50 miles. For the average speed to be 50 mph for the round-trip, the train must travel 50 miles in one hour, but the train already used up that hour on the trip up the hill. Therefore, it is impossible for the train to average 50 mph for the trip.
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DRILL A: SHADOWS – SOLUTIONDuring the day, a 25 foot tall telephone pole casts a 10 foot shadow on the ground. At that same time, a tree casts a 25 foot shadow. How tall is the tree?
This problem can be solved by setting up a ratio.
(POLE) Height / Shadow = (TREE) Height / Shadow
25 ft / 10 ft = y / 25 ft
2.5 = y / 25 ft
62.5 ft = y
10’ 25’
25’
y
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HOMEWORK PROBLEM #1 : SPIDER & FLY
Given: A spider and a fly are in a room whose dimensions are 25 feet wide by 15 feet deep by 8 feet high. The spider is on the CEILING and the fly is on the FLOOR. If one corner of the room represents the origin (0,0,0) of an x-y-z coordinate system, then the spider is located at (20,8,-11 ) and the fly is located at (5,0,-7 ). See the given diagram.
Problem: What is the MINIMUM DISTANCE that the spider must travel to reach the fly?
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HOMEWORK PROBLEM #2 : SPIDER & FLY
Given: A spider and a fly are in a room whose dimensions are 25 feet wide by 15 feet deep by 8 feet high. The spider is on the FLOOR and the fly is on the CEILING. If one corner of the room represents the origin (0,0,0) of an x-y-z coordinate system, then the spider is located at (5,0,-7) and the fly is located at (20,8,-11 ). See the given diagram.
Problem: What is the MINIMUM DISTANCE that the spider must travel to reach the fly?
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DRILL B: Orange & Blue – Diagram Solution
100 Poly students: 75 said they were wearing orange, 95 said they were wearing blue, and 50 said they were wearing both blue and orange.
2545 5095 75
45 + 50 + 25 = 120 students, not 100, so there is something wrong with the survey.
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"METROLOGY is the science and art of measurement. Measurement is extracting information from nature or from devices people have engineered. It is also about the uncertainty in the extracted data, communicating it to other people in a standard way, and making them confident in our measurements by establishing traceable measurement systems.“ Copyright © 1998-2006 Newton Metrology Ltd.
You will now receive a 4-sided concise summary of the International System of Units (SI).
Read and study this summary now, as it may help you to find some answers to the homework.
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STANDARD - An acknowledged measure of comparison for quantitative or qualitative value
ACCURACY -the degree of closeness of a measured or calculated quantity to its actual (true) value
PRECISION - the degree of mutual agreement among a series of individual measurements or values
CALIBRATION - the process of establishing the relationship between a measuring device and the units of measure
TRACEABILITY - an unbroken chain of comparisons relating an instrument's measurements to a known standard
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BASE UNIT – A unit in a system of measurement that is defined, independent of other units, by means of a physical standard. Also known as fundamental unit.
DERIVED UNIT - A unit that is defined by simple combination of base units.
ERROR - The difference between a computed or measured value and a true or theoretically correct value.
PERCENTAGE OF ERROR - the percentage ratio of the error to the correct value of the measured parameter.
UNCERTAINTY - The estimated amount or percentage by which an observed or calculated value may differ from the true value.
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THE INTERNATIONAL SI SYSTEM OF MEASUREMENT IS COMPRISED OF 7 FUNDAMENTAL (OR BASE) QUANTITIES.
THE ENGLISH SYSTEM, USED IN THE UNITED STATES, HAS SIMILARITIES AND THERE ARE CONVERSION FACTORS WHEN NECESSARY.
meter, kilogram, second, Kelvin, etc.
foot, pound, second, Fahrenheit, etc.
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SUMMARY OF THE 7 FUNDAMENTAL SI UNITS:
1. LENGTH - meter
2. MASS - kilogram
3. TIME - second
4. ELECTRIC CURRENT - ampere
5. THERMODYNAMIC TEMPERATURE - Kelvin
6. AMOUNT OF MATTER - mole
7. LUMINOUS INTENSITY - candela
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Exponential Growth – LINEAR GRAPH
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Exponential Growth Curve
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Next, use your PROTRACTOR to divide the circle into 12 equal angles of 30 degrees each.
First, you must locate the center of the circle by finding the midpoint of the given vertical line.
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First, you must locate the center of the circle by finding the midpoint of the given vertical line.
Next, use your PROTRACTOR to divide the circle into 15 equal angles of 24 degrees each.This is similar to the previous problem, except for the size of the angles.
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First, use your ruler to measure the dimensions of the rectangle.
Next, use your ruler to divide the rectangle into thirds from top to bottom, and fourths from side to side.
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212 100
This is the normal boiling temperature of water at sea level.
This is the normal freezing temperature of water at sea level.
32 0
This line represents any temperature on the thermometer.F C
F - 32 C - 0
212 - 32 100 - 0
F - 32 C - 0
212 - 32 100 - 0=
We can now solve for either F or C. Let’s do both!
We can set up a proportion:
TEMPERATURE CONVERSION DERIVATION
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F - 32
212 - 32
C - 0
100 - 0=
F - 32
180=
C
100Cross Multiply
100(F – 32) = 180CDivide by GCF (greatest common factor)
5(F – 32) = 9C
5(F – 32) = 9C 5(F – 32) = 9C
5(F – 32) = C9
This equation is used to solve for C when F is known.
F – 32 = 9C 5
F = 9C + 32 5
This equation is used to solve for F when C is known.
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POLY ENGINEERING2-1
Telephone
T.V. Remote
Alarm Clock
Thermostat
When answering this type of question…
SOURCE of communication to
DESTINATION of communication
The large orange # refers to the test review sheet
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POLY ENGINEERING2-1
INPUTS PROCESSES
OUTPUTS
GOALS
GOALS
FEEDBACKControl
Communication Technology
Transmitted Communication
Encoder Transmitter
Receiver Decoder Storage
Retrieval
Received Communication
Input Process Output
SOURCE DESTINATIONTECHNOLOGY
Inform Persuade Entertain Control Manage Educate
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Telephone CommunicationOne of the simplest devices in your house
You speak into the microphone
InputProcesses
Friend hears voice
OutputEncoderTransmitter
ReceiverDecoderStorage
Retrieval
Microphone – converts sound energy of voice into electrical energy (encodes)Wires – the electrical energy travels from your phone, via exchanges, to your friend’sReceiver – friend’s earpiece speaker converts the electrical energy back to soundAnswering Machine – friend isn’t home, and this machine stores your communicationPlay Button – friend gets home, presses play, hears your recorded voice
What part of this technology system is an example of Human to Machine communication?
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• Television (1925)– Greek: tele – far, Latin: visio – seeing – 4 main parts (cathode ray tube)– Electron gun fires 3 beams – Steering coils move electron beam across screen – Phosphorus screen has over 200,000 pixels– Glass tube holds it all together– Signals are broadcasted like radio signalsTe
leco
mm
unic
ation
sCommunication Technology
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September 30, 2008
1. A device that changes a message into a form that can be transmitted
2. A device that sends a signal (i.e., encoded message)3. A device that acquires a signal (i.e., encoded message)4. A device that changes a coded message into an
understandable form
Decoder
Encoder
Receiver
Transmitter
Data
Match the statements with the correct term below:
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Communication
Knowledge
Information
Storage
1. Unorganized facts2. Organized data3. Information applied to a task4. The sending and receiving of information
Data
Match the statements with the correct term below:
Communication Technology
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POLY ENGINEERING2-2
Last Night’s Homework - REVIEWRadio:
Pulse Modulation: turn the voltage (sine wave) on/off (Morse Code)
Amplitude Modulation: vary the amplitude (peak-to-peak) voltage
Frequency Modulation: vary the frequency (speed)
PM
AM
FM
Encoder: Devices that convert sound and information into a modulated sine wave
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– Print Graphic Communication Visual, lingual messages that include printed media
– Photographic Communication Using photographs, slides, or motion pictures to
communicate a message– Telecommunications
Communicating over a distance– Technical Graphic Communication
Specific information about a product or its partsSize and shape, how to install, adjust, operate, maintain,
or assemble a device
Classes of Communication Technology
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– Major Processes:• Relief
– A modeled work that is raised (or lowered) from a flat background.
– Cuneiform by the Sumerians ~6000 years ago. – Wood block printing ~200 C.E.– Movable type printing ~1040 C.E. (Gutenberg ~1450)– Intaglio (in-tal-yo) ~1430– Rotary printing press ~1843
• Lithography (offset printing) ~1796– The source and destination are not on raised surfaces– Grease and water do not readily mix– A chemical process– Most modern books and newspapersPr
int G
raph
ic C
omm
unic
ation Intaglio
(in-tal-yo)
1. Depressions cut into printing plate
2. The plate is covered in ink
3. Excess ink is removed from surface
4. Paper placed on plate and compressed
5. Paper is removed and ink has been transferred
By 593 A.D., the first printing press was invented in China, and the first printed newspaper was available in Beijing in 700 A.D. It was a woodblock printing. And the Diamond Sutra, the earliest known complete woodblock printed book with illustrations was printed in China in 868 A.D. And Chinese printer Bi Sheng invented movable type in 1041 A.D. in China.
Low ReliefHigh Relief
Communication Technology
Cuneiform
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• Screen Printing (~1000 C.E., China; 1907 England)– Mainly billboards, package labels, fabric designs– Uses a woven mesh (a screen) to support an ink
blocking stencil. – The stencil forms open areas of mesh that transfer ink
as a sharp-edged image onto a substrate. – A roller or squeegee is moved across the screen
stencil forcing or pumping ink past the threads of the woven mesh in the open areas.
• Electrostatic (1938 / 1960s)– Photocopier, Laser Printer– Opposite charges attract
• Ink Jet (1980s)– Use a series of nozzles to spray ink directly on paperPr
int G
raph
ic C
omm
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ation
Communication Technology
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• Telecommunication– Communicating over a distance
Tele – Greek, “far off” Communicare – Latin, “to share”– Rely on the principles of electricity and magnetism – 2 types:
• Hardwired systems (telephone, cable, fiber-optic)• Broadcast systems (radio and t.v., mobile phones)
– Point-to-point: • One transmitter and one receiver
– Broadcast:• One powerful transmitter to numerous receiversTe
leco
mm
unic
ation
sCommunication Technology
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– Smoke signals and drums– Chains of beacons (Middle Ages)
• Navigation signals• Enemy troops approaching
– Homing pigeons • Carrier pigeons used as early as 1150 in Baghdad• Olympic victors, Greece; Stock options, Europe
– Optical telegraph (semaphore, 1792, France)• Towers with pivoting shutters• Information encoded by the position of the
mechanical elementsTele
com
mun
icati
ons
Communication Technology
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– Telegraph (mid 1830s)• First instrument used to send messages by means of wires
and electric current• A device interrupts the flow of a current through a wire• Uses shorter and longer bursts of current to represent
letters• Device at receiving end converted electrical signal into
clicks• Operator/mechanical printer converted clicks into words• Telegram – wires over land• Cable – wires under water
– Telephone (1876 – Bell and Gray)• Greek: tele – far, phone – sound
Tele
com
mun
icati
ons
Communication Technology
• Orthographic Projections:– Ortho: straight or at right angles– Graphic: written down– Pro: forward– Jacere: to throw“To throw straight forward and write down”
• The method of representing the exact form of an object in 2 or more views on planes (usually at right angles to each other)
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POLY ENGINEERING2-9
MULTI-VIEWTY
PE 2
: MU
LTI-V
IEW
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POLY ENGINEERING2-9How are orthographic projections drawn?
MULTI-VIEWTY
PE 2
: MU
LTI-V
IEW
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POLY ENGINEERING2-9
• Reference Planes:–Frontal Reference Plane
»Front View–Horizontal Reference Plane
»Top View–Profile Reference Plane
»Side View
MULTI-VIEWTY
PE 2
: MU
LTI-V
IEW
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POLY ENGINEERING2-9
• Sectional Views– How an object looks if a cut were made through it
perpendicular to the direction of sight.– For example, if we cut the shape below at PRP 2 and
drew the shape (including its “insides”) we would have a sectional view:
SECTIONAL VIEWSTY
PE 2
: MU
LTI-V
IEW
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• Sectional Views– Different materials have different sectional views
SECTIONAL VIEWSTY
PE 2
: MU
LTI-V
IEW
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A
Com
mun
icati
on T
echn
olog
y
DRILLOctober 10, 2008
If point A is 2’-3” away from the FRP in the right view, point A will ALWAYS be 2’-3” away from the FRP.
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POLY ENGINEERING2-10
AUXILIARY VIEWSTY
PE 2
: MU
LTI-V
IEW
FRP
PRP
Which Reference Plane?HRP
ARPAuxiliary Reference Plane
The ARP shows true form (shape and size) for inclines
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TYPE
2: M
ULT
I-VIE
WSURFACE DEVELOPMENTS
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ISOMETRICTY
PE 3
: PIC
TORI
AL
Isometric Cube:
1) all lines equal length;
2) all faces equal area;
3) perimeter is a hexagon
• From Greek: Equal Measure– Isos: Equal– Metron: Measure
• The scale along each axis of the projection is the same• True form parallel lines are shown as parallel (note colors
below)• All isometrics: simple construction
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POLY ENGINEERING2-10
• Latin: perspicere – to see through• An approximate representation of an image as it is
perceived by the eye. • The most characteristic feature of perspectives is that
objects are drawn:
Smaller as their distance from the observer increases
PERSPECTIVETY
PE 3
: PIC
TORI
AL
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POLY ENGINEERING2-10
• A way of showing depth, like isometric• Part orthographic / part isometric:
– One face is true form– Parallel lines behind; either:
» Full scale» Half scale» Three-quarter scale
OBLIQUETY
PE 3
: PIC
TORI
AL
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POLY ENGINEERING2-10
• Take an object and separate into individual parts• Usually employed in instruction manuals• Typically drawn in parallel projection (notice there
is no perspective in the examples below)
EXPLODED ASSEMBLYTY
PE 3
: PIC
TORI
AL
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POLY ENGINEERING2-10
• Show the interior details of a product• Often employed in instruction manuals• Assists in understanding operation of product
CUT-AWAY PICTORIALTY
PE 3
: PIC
TORI
AL
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POLY ENGINEERING2-11
• Turn in your 3-view assignment (include NAME)• Match the type of Technical Graphics below with
its type:
Isometric Section Standard View Development Perspective Oblique
Cut-away Pictorial
Com
mun
icati
on T
echn
olog
y
DRILLOctober 13, 2008
A B C
D E F
G
E
B
C
F
G
D
A
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Which of the following images are parallel projections?
TECHNICAL GRAPHICSTe
chni
cal G
raph
ic C
omm
unic
ation
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1. Line Weights2. Line Types3. Dimensioning4. Scales
CLASS STANDARDSTe
chni
cal G
raph
ic C
omm
unic
ation
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POLY ENGINEERING2-11
Four Weights in this class:
Light: not noticeable from 2’ (nearly invisible)Medium: just noticeable from 2’Heavy: obvious from 2’ (final weight for most
objects)Very Heavy: only used for borders
LINE WEIGHTSTe
chni
cal G
raph
ic C
omm
unic
ation
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1. Construction/Layout Lines– LIGHT WEIGHT– ALL lines begin as these– DO NOT ERASE (unless there is a measuring error)
2. Guidelines– LIGHT WEIGHT– Used for LETTERING
LINE TYPESCL
ASS
STA
NDA
RDS
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POLY ENGINEERING2-11
3. Object Lines:– HEAVY WEIGHT– The final line type for most
objects
4. Hidden Lines:– HEAVY WEIGHT– Everything must be represented in each view, whether
or not it can be seen– Interior and exterior features are projected from view
to view in the same way– Parts not seen on the exterior of a view are drawn
with hidden lines – short DASHES
LINE TYPESCL
ASS
STA
NDA
RDS
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5. Centerlines:– MEDIUM WEIGHT– Centers of symmetrical objects, including circles– Used to locate views and dimensions
LINE TYPESCL
ASS
STA
NDA
RDS
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POLY ENGINEERING2-11
6. Extension Lines:– MEDIUM WEIGHT– Extend from objects – Used for dimensioning
7. Dimension Lines:– MEDIUM WEIGHT– Used for dimensioning– Go between extension lines
LINE TYPESCL
ASS
STA
NDA
RDS
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CLAS
S S
TAN
DARD
S
• 2 things are needed to describe an object completely:– Shape – Size
• Dimensioning: Size description– Units are required– Decimal or Fraction– Dimensions read from bottom or right side
• Include:– Extension line: begin 1/16” away from object and extend
1/16” beyond Dimension Line– Dimension line: use arrowheads, guidelines, and LETTER
DIMENSIONING
PREFERRED
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QUIZ – Slide 1Te
chni
cal G
raph
ic C
omm
unic
ation 1. Write the correct name for each drawing type next to
the correct letter on your paper.
A B C D
E F G
QUIZ – Slide 4Te
chni
cal G
raph
ic C
omm
unic
ation 4. Give an example of something a designer would
scale up for drawing.5. Give an example of something a designer would
scale down for drawing.6. If a point on an object is 14’-3” away from the
frontal reference plane in the front view and 7’-6” away from the horizontal reference plane in the front view, how far away is the point from the frontal reference plane in the right side view?
7. To draw what type of drawing would designers use more than one position for any reference plane?
1. Add width of front view to width of right view (depth).
2. Add the space we will put between: 1.5”
4.5” + 2” = 6.5”
HORIZONTAL STARTING POINT
6.5” + 1.5” = 8”
3. Subtract from the total width.10” – 8” = 2”
4. Divide by 2.Horizontal Starting Point = 1”
1. Add height of front view to height of top view (depth).
2. Add the space we will put between: 1.5”
3” + 2” = 5”
VERTICAL STARTING POINT
5” + 1.5” = 6.5”
3. Subtract from the total height.7.25” – 6.5” = .75” = 3/4”
4. Divide by 2.Vertical Starting Point = .375” = 3/8”
Vertical Starting Point is 7/8”
Horizontal Starting Point = 1”
review
Thursday’s TestYou will be given the sheet below, including the
border and title block. 1. Draw lettering guidelines 1/16” 2. Complete title block3. Calculate starting point (vertical and horizontal) – NO
CALCULATOR ALLOWED
IOT
POLY ENGINEERING
IOT
POLY ENGINEERING2-18
• Isometrics are drawn with:– All object vertical lines are vertical– All object horizontal lines are drawn 30 degrees
from the horizontal– All lines are drawn true size
DRAWING ISOMETRICSTe
chni
cal G
raph
ic C
omm
unic
ation
IOT
POLY ENGINEERING2-18
• One of the most effective ways to sketch an object pictorially is to sketch it in isometric.1. Start by sketching an enclosing box (absolute
height, width, depth) – Construction Lines2. Add in features3. Darken all final lines
Tech
nica
l Gra
phic
Com
mun
icati
onDRAWING ISOMETRICS
IOT
POLY ENGINEERING2-18
• Front view is typically drawn first• You must look at all views
Tech
nica
l Gra
phic
Com
mun
icati
onISOMETRICS from ORTHOGRAPHICS
Let each grid space = ½”
IOT
POLY ENGINEERING2-21
1. Describe an isometric view2. Prepare drawing paper3. Locate center of drawing space4. Plot starting point of drawing5. Complete isometric drawing
Tech
nica
l Gra
phic
Com
mun
icati
on
DRAFTING ISOMETRIC DRAWINGS
IOT
POLY ENGINEERING2-21
1. Describe an isometric view1. Height2. Width 3. Depth
(of the front view)
Tech
nica
l Gra
phic
Com
mun
icati
onDRAFTING ISOMETRIC DRAWINGS
2. Prepare drawing paper3. Locate center of drawing space
Tech
nica
l Gra
phic
Com
mun
icati
onDRAFTING ISOMETRIC DRAWINGS
45 degree triangle
Construction Lines
4. Plot starting point of drawing
Tech
nica
l Gra
phic
Com
mun
icati
on
DRAFTING ISOMETRIC DRAWINGS
30-60-90 triangle
1) ½ W2) ½ D3) ½ H
Starting Point
IOT
POLY ENGINEERING2-21
5. Complete isometric drawing
Tech
nica
l Gra
phic
Com
mun
icati
on
DRAFTING ISOMETRIC DRAWINGS
Starting Point
IOT
POLY ENGINEERING2-21
Tech
nica
l Gra
phic
Com
mun
icati
on
DRAFTING ISOMETRIC DRAWINGS
review
Thursday’s TestYou will be given the sheet below, including the
border, title block, and isometric guidelines. 1. Draw lettering guidelines 1/16” 2. Complete title block3. Calculate starting point
1. Draw “X” across drawing space2. Pick the nearest intersection3. Measure down to right ½ width4. Measure down to left ½ depth5. Measure straight down ½ height
4. Each grid space = ¼”
IOT
POLY ENGINEERING
IOT
POLY ENGINEERING2-3
Absolute coordinates are based on the origin (0,0), expressed as an ordered pair x,y. All other points are also expressed in the form x,y and the values of x and y are based on the distance from the origin.
If we desire to draw a line, we must give the location of both endpoints, expressed as an ordered pair x,y where the origin is used as a reference point.
Absolute Coordinates
IOT
POLY ENGINEERING2-24
Communication TechnologyIntroduction to AutoCAD
Relative coordinates are not based on the origin (0,0). Instead, we use the @ symbol followed by an ordered pair x,y. This means “starting where we are AT, go over (or back) x and up (or down) y.
If we desire to draw a line using relative coordinates, we must give the location of the first endpoint (usually using Absolute coordinates), followed by @x,y for the second endpoint.
IOT
POLY ENGINEERING2-3
Polar Coordinates
Polar coordinates are used to draw lines at specific angles.
When using Polar coordinates, angles are measured according to the following tradition:
0
90
180
270
30
90
150
210
270 = -90
330 = -30
ISOMETRIC ANGLES
IOT
POLY ENGINEERING2-26
Polar Coordinates
Polar coordinates are used to draw lines at specific angles.
When using Polar coordinates, angles are measured according to the following tradition:
0
90
180
270
45 degrees
135 degrees
225 degrees = -135 degrees
315 degrees = -45 degrees360 degrees = 0 degrees