1. MECHANICAL DRAWING

2. Why do we draw? To communicate!!! Picture is worth a 1000 words!!!
words are pretty effective for some situations, often in Engineering and design, pictures are much more effective
Importance of communication
- what’s your idea worth if you cant share it with others
In the real world you have to collaborate, so you need to know how to communicate your ideas or they are not very useful to you

3. Why does it matter?
What’s the use of a great idea if you cant convey it to any one else.
No one is an expert at everything, so we must collaborate to reach a common goal.
Picture is worth a 1000 words!!!
words are pretty effective for some situations, often in Engineering and design, pictures are much more effective
Importance of communication
- what’s your idea worth if you cant share it with others
In the real world you have to collaborate, so you need to know how to communicate your ideas or they are not very useful to you

4. Communication with Drawing (things to consider)
Subject – what you are trying to convey (Process, structure, function, material, etc….) Audience – who you are communicating with (designer, client, manager, public, other engineers)
Two important things to think about when drawing

5. Types of Mechanical Drawing
Drawing types we will explore today
Sketches
Isometric Drawings
Orthographic Projections

6. When is a sketch useful? Think about What (subject) Who (audience)
USEFULL: Idea sharing / working out low level details / idea generating
NOT SO USEFULL: PART MANUFACTURE OR ASSEMBLE

7. Sketching
– look and feel

8. Sketching
– to show process

9. Sketching – to explore form
Sketching usually associated with look and feel, try and emphasize that other models are at times effective.
EX (restaurant floor plan)

10. DRAWING TOOLS drafting dots or masking tape thick marker thin marker
ruler or scale
triangle

11. Time to Draw!!!!!!!!
Bring your markers and pencil and move to one of the large tables in Pappalardo

12. WARM UP (in marker, without erasers and rulers)
connect the matching letters and symbols without lifting your marker, draw from your shoulders, not your wrist – STAND UP 
to the side – try drawing a few circles without lifting your marker
try inscribing some circles in the squares you’ve just created
can you make the circle touch the center of each side of the square?
can you do it without lifting your pen?
try inscribing ovals in the three orientations of diamonds created by two of your neighboring triangles
can you make the oval touch the center of each side of the diamond?

13. When is a technical drawing useful?
Think about
What (subject)
Who (audience)
USEFULL: assembly, machining, fabrication,
NOT SO USEFULL: quick idea generation, or communication of rough concepts

14. Technical Drawing - Isometric

15. Technical Drawing – Orthographic

16. Technical Drawing – Assembly section

17. Technical Drawing – More Sections

18. Isometric Drawing

19. Isometric Drawing

20. Isometric Drawing front corner is centered and vertical
bottom edges slant up at a 30 degree angle from horizontal
(You should be viewing 3 of the 6 faces of a cube)
30°
30°

21. ISOMETRIC DRAWING
height (“vertical”) lines are always drawn vertically in at their true (or scaled) length
width and depth (“horizontal”) lines are drawn 30 degrees from the horizontal at their true (or scaled) length
all lines parallel to the height, width or depth are at their true (or scaled) length
lines not parallel to these axes are not drawn at their true length
height
width
depth

22. Isometric Drawing - Dimensions

23. Isometric Drawing - Dimensions
Identify line to dimension

24. Isometric Drawing - Dimensions
Draw extension lines

25. Isometric Drawing - Dimensions
Draw dimension lines

26. Isometric Drawing - Dimensions
draw as many dimensions as you would need to make the part
(no more no less)

27. DRAWING TOOLS drafting dots or masking tape thick marker thin marker
ruler or scale
triangle

28. Time to draw!!!!!!
Take all your drawing tools and move to the tables in pappalardo.

29. ISOMETRIC PRACTICE draw a 8cm cube (use pencil and a ruler at first)
1 – draw a single vertical (centered, starting at the bottom)
2 – draw the depth and width of the cube from the bottom of the vertical (30 degrees to the horizontal)
3 – draw the other two verticals
4 – draw the top of the cube
trace over your cube freehand with your thin marker
affix isometric graph paper to work space with draft dots
cover with trace
I will do on the board as they do on their page

30. ISOMETRIC PRACTICE – 3D “L”
draw a rectangular prism (use pencil and a ruler at first)
1 – use any height, width and depth – same steps as the cube
2 – lightly trace the hidden lines of the bottom plane
3 – draw the L on the bottom and top plane, with the negative space “closest” to you
4 – fill in the remaining verticals
5 – erase extra lines
trace over your lines with the thin marker, then trace around the outermost edges of your shape with the thick marker
cover with fresh trace
I will do on the board as they do on their page

31. ISOMETRIC PRACTICE - CIRCLE
inscribe circles on each face of the cube
1 – in pencil, lightly divide each face into four equal sections by connecting the opposite edge midpoints
2 – (in marker) draw arcs in each of the four sections, connecting the midpoints of each edge and creating three inscribed circles
reaffix cube trace
I will do on the board as they do on their page

32. ISOMETRIC PRACTICE – more complex objects
draw one of the shapes in pencil at 1:2 scale
you will need to measure the shape
pick the appropriate orientation – the one that gives the most detail about the object and its features
start with a cube
remember – vertical lines, or lines in horizontal planes should be drawn first, then other lines (which may not be true length) can be drawn last to connect appropriate edges
trace over your object with your thin marker, then trace around the outermost edges of your object with the thick marker
hand out shapes
I will walk around and see how they’re doing
at the end I will ask who couldn’t fully express their shape with isometric? this will lead into orthographic

33. did anyone have an object that couldn’t be fully expressed with a single isometric drawing?

34. ORTHOGRAPHIC PROJECTION
Isometric Drawing

35. ORTHOGRAPHIC PROJECTION

36. ORTHOGRAPHIC PROJECTION

37. ORTHOGRAPHIC PROJECTION

38. ORTHOGRAPHIC PROJECTION

39. ORTHOGRAPHIC PROJECTION

40. ORTHOGRAPHIC PROJECTION

41. ORTHOGRAPHIC PROJECTION

42. ORTHOGRAPHIC DRAWING – PLANNING
what is the minimum number of views required to capture every object feature? often the answer is three, but it could be less or more!
what is the best way to lay out these drawings
best use of paper, should drawings be scaled up or down?
we will be dimensioning drawings, so leave enough space around each view to add dimensions
think about the order of inking to avoid smudging

43. ORTHOGRAPHIC DRAWING – LINEWEIGHTS AND STYLES
thick continuous line – used for visible edges and outlines
thin continuous line – hatching, short center lines, dimensions or projection lines
thin dash-dot line – center lines, to identify the center of a circle or a line of symmetry
thin dashed line – used for important hidden detail, such a hole in a solid or a wall thickness

44. ORTHOGRAPHIC DRAWING – DIMENSIONING
draw as many dimensions as you would need to make the part, no more, no less
do not add redundant dimensions, will lead to conflicts with tolerances – if you can deduce a dimension from other displayed dimensions, it is redundant
often better to continually measure from one point than measuring from one point to another

45. ORTHOGRAPHIC DRAWING – DIMENSIONING CIRCLES AND RADII
dimensioning circles – all dimensions proceeded by Ø – note use of center lines
two projected lines from a diameter (least used)
internally along the diameter, labeled internally or externally, depending on size
if circle is very small, can dimension from outside the circle using an arrow which points towards the center
dimensioning radii – all dimensions proceeded by R – should only have one arrowhead, and arrow should pass through circle center
can locate the center of the circle with center lines and an arrow with the measurement outside the circle
can dimension with an arrow originating from the center without center lines, label at center of circle

46. ORTHOGRAPHIC DRAWING – PAGE LAYOUT
all of your drawings should include:
title of part
your name
date of drawing
version (if a previous drawing of the part exists)
scale (dimensions will always be represented as if the drawing is 1:1, actual size)
1:1 – actual size
2:1 – drawing is twice as big as object
1:2 – drawing is half as big as object
a few words about dimensions
all measurements are in mm – we’ll do this
all measurements are in inches
these should be written neatly on the drawing sheet, each item is usually surrounded by a thin box, and the items are generally adjacent – like a table

47. Time to Draw
Take all your drawing materials and move back to Pappalardo.

48. ORTHOGRAPHIC PRACTICE
try drawing your 3D L with the orthographic technique
affix real paper with drafting dots

49. ORTHOGRAPHIC PRACTICE
try drawing one of the ten objects with the orthographic technique
will need to measure the object
can use ruler and pencil at first
trace over lines with appropriate marker
write scale and other page layout items on your drawing
don’t forget to dimension your drawing!
affix real paper with drafting dots

50. HOMEWORK – due Monday
draw something from your life at WTP, later you’ll model it in SolidWorks and create the isometric and orthographic drawings from the 3D model – use trace
isometric
orthographic with dimensions and proper layout
examples from other years
phones, cameras, etc.
fun challenge: try drawing an object or two using only your thin and thick pens, without a ruler, pencil, straightedge or triangle – see how close to isometric you can get freehand – in your design notebook
using a pen to sketch is important because you can’t erase. cultivating this skill will teach you to draw only the lines that you really mean to draw. you should never erase your ideas – design is an iterative process, and sketches show the progression of your design – and you may be able to use ideas or elements from earlier designs

51. ORTHOGRAPHIC DRAWING – DIMENSIONING HOLES
use the skills from dimensioning everything else
diameter symbol
as many views as required to fully understand hole
center lines and symmetry lines

52. ORTHOGRAPHIC – SECTIONS
often interior features can not be fully described by isometric and orthographic drawings – rather than struggling with hidden lines, a section may be more easy to create and more easy to understand’
imagine slicing the object along a plane
don’t forget line weights and centerlines
hatch material that is touching the slice plane
label orthographic drawing A-A (or B-B) to show where the slice was taken
orthographic sections are much more common than isometric sections

53. How do I bring this to the classroom??????
Use sketching for general design, planning and idea sharing
Look and feel
Form
process
Use technical drawing for final details such as assembly or part drawings for fabrication
Isometric
Orthographic
Assembly
SKETCHING
FORM – where do I place my grabber arm, ballast
PROCESS – water sampler, what are the steps, final collaboration what are the steps to recover cargo, sunken ship?