Engineering Drawing Basics

http://en.wikipedia.org/wiki/Engineering_drawing

Engineering drawings are usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance (such as typefaces and line styles), size, etc. One such standardized convention is called GD&T.
The purpose of such a drawing is to accurately and unambiguously capture all the geometric features of a product or a component. The end goal of an engineering drawing is to convey all the required information that will allow a manufacturer to produce that component.


Geometry – the shape of the object; represented as views; how the object will look when it is viewed from various standard directions, such as front, top, side, etc.
Dimensions – the size of the object is captured in accepted units.
Tolerances – the allowable variations for each dimension.
Material – represents what the item is made of.
Finish – specifies the surface quality of the item, functional or cosmetic. For example, a mass-marketed product usually requires a much higher surface quality than, say, a component that goes inside industrial machinery.

Line styles and types

Standard engineering drawing line types:
A variety of line styles graphically represent physical objects. Types of lines include the following:
visible – are continuous lines used to depict edges directly visible from a particular angle.
hidden – are short-dashed lines that may be used to represent edges that are not directly visible.
center – are alternately long- and short-dashed lines that may be used to represent the axes of circular features.
cutting plane – are thin, medium-dashed lines, or thick alternately long- and double short-dashed that may be used to define sections for section views.
section – are thin lines in a pattern (pattern determined by the material being "cut" or "sectioned") used to indicate surfaces in section views resulting from "cutting." Section lines are commonly referred to as "cross-hatching."

Orthographic projection
The orthographic projection shows the object as it looks from the front, right, left, top, bottom, or back, and are typically positioned relative to each other according to the rules of either first-angle or third-angle projection.
First angle projection is the ISO standard and is primarily used in Europe. The 3D object is projected into 2D "paper" space as if you were looking at an X-ray of the object: the top view is under the front view, the right view is at the left of the front view.
Third angle projection is primarily used in the United States and Canada, where it is the default projection system according to BS 8888:2006, the left view is placed on the left and the top view on the top.
Not all views are necessarily used, and determination of what surface constitutes the front, back, top and bottom varies depending on the projection used.

Isometric projection
The isometric projection show the object from angles in which the scales along each axis of the object are equal. Isometric projection corresponds to rotation of the object by ± 45° about the vertical axis, followed by rotation of approximately ± 35.264° [= arcsin(tan(30°))] about the horizontal axis starting from an orthographic projection view. "Isometric" comes from the Greek for "same measure." One of the things that makes isometric drawings so attractive is the ease with which 60 degree angles can be constructed with only a compass and straightedge.
Isometric projection is a type of axonometric projection. The other two types of axonometric projection are:
Dimetric projection
Trimetric projection

[edit] Oblique projection
An oblique projection is a simple type of graphical projection used for producing pictorial, two-dimensional images of three-dimensional objects:
it projects an image by intersecting parallel rays (projectors)
from the three-dimensional source object with the drawing surface (projection plan).
In both oblique projection and orthographic projection, parallel lines of the source object produce parallel lines in the projected image.

[edit] Perspective
Perspective is an approximate representation on a flat surface, of an image as it is perceived by the eye. The two most characteristic features of perspective are that objects are drawn:
Smaller as their distance from the observer increases
Foreshortened: the size of an object's dimensions along the line of sight are relatively shorter than dimensions across the line of sight.

Trade and industrial education- Quiz 1

Quiz 1
The correct answer for each question is indicated by a .
1
Correct
The acronym CADD stands for
A)
computer-assisted drawing and design.
B)
computer-aided drafting and design.
C)
computer-aided design and drafting.
D)
computer-assisted design and drafting.
2
Correct
The acronym CAD stands for
A)
computer-aided design.
B)
computer-assisted design.
C)
computer-assisted drafting.
D)
computer-aided design and drafting.
3
Correct
Release 1.0 (Release 1) of AutoCAD LT® was developed and released in
A)
1988
B)
1991
C)
1993
D)
1996
4
Incorrect
The minimum amount of RAM recommended by Autodesk to run the most recent version of AutoCAD LT® is
A)
200 MB.
B)
256 MB.
C)
236 MB.
D)
300 MB.
5
Incorrect
The text Hands-On AutoCAD LT® is based specifically on AutoCAD LT® Version
A)
2000
B)
2000i.
C)
2002
D)
2004
6
Correct
AutoCAD Mechanical® was designed and developed for
A)
2D mechanical engineering, design, and drafting.
B)
the mechanical and electrical design of industrial machinery.
C)
the engineering design of subdivision, site, road, sewer, and drainage projects.
D)
the creation and maintenance of maps.
7
Correct
Autodesk Inventor® was designed and developed for
A)
2D mechanical engineering, design, and drafting.
B)
the mechanical and electrical design of industrial machinery.
C)
the engineering design of subdivision, site, road, sewer, and drainage projects.
D)
the creation and maintenance of maps.
8
Correct
Drafting dates back to pictorial images etched into
A)
concrete slabs.
B)
cast iron pads.
C)
stone tablets.
D)
ceramic plates.
9
Correct
Early pictorial drawings later evolved into more highly detailed images called
A)
technical drawings.
B)
blueprints.
C)
whiteprints.
D)
technical sketches.
10
Incorrect
Technical drawings are
A)
generally pictorial in nature.
B)
usually freehand sketches.
C)
used for design purposes only.
D)
drawn to an exact set of rules using specific techniques.

Roller Coaster Design Plan

Must have:
- initial drop ( 40-80 metres high )
- 1 loop
- 1 hill
- a theme
- riders must not experience more than 6 Gs at any point

( bends are optional )

Artistic Drawing and perspective

www.technologystudent.com

Single perspective drawing- Perspective drawing is a good style to use when drawing in 3D. There are different styles including single point and two point perspective. The basic example below shows how to construct a simple single point perspective drawing of a cube. Using the same skills more complex drawings/designs can be drawn, after a little practice.http://www.technologystudent.com/designpro/perspec1.htm

Two point perspective- Perspective is a realistic way of drawing objects in 3D. We have already looked at single point perspective, two point perspective using two vanishing points and when an object is drawn in this way it is even more realistic than if it were to be drawn with a single vanishing point.http://www.technologystudent.com/designpro/twopers1.htm

Applying the Metric and Imperial Systems of Measurement

Applying the Metric and Imperial Systems of Measurement

Systems of measurement are used to measure the length, volume, mass or temperature of an object.

The Metric System
Canada and most other countries of the world use the metric system of measurement.
Using the metric system, fill in the main unit of measure for each category:

Length: Millimetre Volume: Litres Mass: Kilogram Temp: Celsius

Some of the commonly used units and conversions in the metric system are as follows:
Length Volume Mass
10 mm = 1 cm 1000 mL = 1 L 1000 g = 1 kg
100 cm = 1 m 1000 kg = 1 t
1000 m = 1 km
1. If a wall is measured to be 450 cm long, what is the measurement in metres (m)?

4.5 metres


2. If a container has a volume of 2.6 L, what is the volume in millilitres (mL) ?

2600 mL


3. Consider the following examples of objects that could be measured. Match the examples with the most appropriate unit of measurement by drawing lines between them.

Column A Column B

Volume of a cooler 170 cm

Mass of an average person 22º C

Temperature inside a room 10 mm

Thickness of a magazine 75 Kg

Height of an average person 20 L

Distance around a running track 400 m




Applying the Metric and Imperial Systems of Measurement

The Imperial System
Some other countries, particularly the United States, use a different system of measurement called the imperial system. Although it is not recognized as Canada’s main system of measurement, why is it still important for us to be able to understand and work with the imperial system?





In the case of the imperial system, fill in at least one example of a unit of measure for each category:

Length: inch Volume: pint Mass: pound Temperature: Fahrenheit

Some of the commonly used units and conversions in the imperial system are as follows:
Length Volume Mass
12 inches = 1 foot 16 fluid ounces = 1 pint 16 ounces = 1 pound
3 feet = 1 yard 2 pints = 1 quart 2000 pounds = 1 ton (US)
1760 yards = 1 mile 8 pints = 1 gallon
4. If a wall is measured to be 144 inches long, what is the measurement in feet?

17.28 ft


5. If a container has a volume of 6 quarts, what is the volume in pints?

12 pints


6. Consider the following examples of objects that could be measured. Match the examples with the most appropriate unit of measurement by drawing lines between them.
Column A Column B

Volume of a cooler ½ in. (inches)

Mass of an average person 5’10” (5 feet, 10 inches)

Temperature inside a room 5 gal (gallons)

Thickness of a magazine 175 lb. (pounds)

Height of an average person 200 yd. (yards)

Distance around a running track 72º F
Converting between the Metric and Imperial Systems

The following are approximate conversions between commonly used metric and imperial measurements:
Length Volume Mass

30.48 cm = 1 foot 29.574 mL = 1 fluid ounce 28.35 g = 1 ounce
2.54 cm = 1 inch 0.473 L = 1 pint 0.454 kg = 1 pound
1.6 km = 1 mile 3.785 L = 1 gallon 0.907 t = 1 ton (US)
1m = 3.28 feet

Temperature: Farenheit to Celcius { }
Celcius to Farehneit { }

7. If a wall is measured to be 14 feet long, what is the measurement in cm?


426.72 cm



8. If a container has a volume of 4 L, what is the volume in gallons?


1.06 gallons























Conversions

1. Convert the following metric measures:

a) 2400 m = 2.4 km
b) 34 cm = 340 mm
c) 5 L = 5000 mL
d) 3200 g = 3.2 kg

2. Convert the following imperial measures:
a) 4 pounds = 64 ounces
b) 6.5 quarts = 13 pints
c) 42 inches = 3.5 feet
d) 3 miles = 5280 yards

3. Convert the following metric and imperial measures:
a) 36 inches = 91.44cm
b) 40 km = 24.9 miles
c) 10 gallon = 37.85 L
d) 140 g = 4.94 ounce
4. Estimate the following measures using an appropriate unit of measure:
a) the length of your foot: 20 cm
b) the volume of a carton of milk: 1 L
c) the height of the classroom: 10 ft
d) the width of your thumbnail: 15 mm

5. Jesse needs to order flooring for his room. He measured the dimensions of the room to be 300 cm by 375 cm. However, the flooring company needs to know these dimensions in feet. Find the dimensions of the room in feet.
10 ft by 12.5 ft

6. A square room has area 49m2. What is the area in square feet?
527.2 square ft

7. **A cube has volume 1000 cubic feet. What is the volume in cubic metres? If one cubic cm is equal to one mL, what is the volume of this cube in litres?
28.3 cubic metres

Answers:

a) 2.4 km b) 340 mm c) 5000 mL d) 3.2 kg
a) 64 ounces b) 13 pints c) 3.5 feet d) 5280 yards
a) 91.44 cm b) 24.9 miles c) 37.85 L d) 4.94 ounces
a) 20 cm (will vary) b) 1 L (will vary) c) 10 feet (will vary) d) 15 mm (will vary)
10 feet by 12.5 feet
527.2 square feet
28.3 cubic metres, 28,300 L

Co-ordinate drawing

Trimming and offsetting

Star Thing