1. Mechanical Engineering Drawing MECH 211/M
Lecture #11; Chapter 14
Dr. John Cheung

2. Concurrent Design DESIGN PROCESS Identification of design problem
Problem-solving concepts and ideas
Compromise solutions
Models or prototypes
Production or working drawings

3. 3D Models

4. Technical Documentation
Developed for each new product
Maintained over the product's life cycle
Includes
Working drawings (Assembly & Component)
Calculations
Technology details
Assembly scheme
Regulatory Compliance
Much more

5. Working Drawings Made for each non-standard component
Component Working Drawings
Used for manufacturing
Assembly Working Drawings
Shows how components are assembled
Shows how many and what components are needed
Recommendation
Use reference material when creating a working drawing
Adhere to standards

6. Working Drawing

7. Working Drawing

8. Working Drawing

9. Working Drawing Detail Drawing A working drawings of
an individual part
Single or multiple sheets
Neatly made
Checked and signed by drafter and Senior Engineer
Assembly drawings are done on a separate sheet

10. Part Name and Number
Located in the drawing area

11. Drawing Form Drawing format is standardized within an organization
The scale is selected to make sure that the component would fit the format
A preliminary evaluation should be performed before the drawing is completed
Take into consideration the space for dimensions

12. Drawing Form
Refer front inside cover of the book for details

13. Drawing Form
John Peach

14. Title Blocks
Used to record important information and keep track of the parts
Name and address of the company
Title of the drawing
Drawing number
Names of the designers
Completion date
Design approval
Additional approval
Scale
Supply code for manufacturers
Weight of the item
Standards vary with paper size and organization

15. Drawing Numbers All drawings are numbered Serial numbers
lower right or upper left corner of sheet
Serial numbers
Codified information
Indicating functionality
Model No.
Paper size
Revision Number

16. Bill of Materials Consists of itemized list of parts
Two possible locations
Above title block
Top right corner
Numbering
Largest parts first
Standard parts last
If above title block, it is numbered upwards
If in the top right corner, it is numbered downwards
Contains
Part numbers and title
Quantity
Other relevant info

17. Revisions Revisions are required due to changes in design
Revisions are numbered and documented
The track of modifications is kept on the drawing
CAD allows additional information to be tracked
New drawing are made to replace
large changes
OBSOLETE stamped on old

18. Simplifying the Design Process
Use text description to eliminate the need for a:
Drawing
Projected views
Detailed drawing of standard parts (threads, gears etc.)
Use descriptions like e.g. HEX, SQ, DIA, R
Show partial views of symmetrical objects
Avoid elaborate, pictorial or repetitive detail.

19. Simplifying the Design Process
When necessary to detail threads, do not show them over the whole length.
Eliminate detail of nuts, bolt heads, and other standard parts. Show outlines and position only.
Reduce detail of parts on assembly drawing
Avoid unnecessary hidden lines that add no clarification
Use sectioning only when it is necessary for the clarity

20. Simplifying the Design Process
For holes and tapped holes use symbols
Omit views with no dimensional or written instructions
A smaller drawing is usually easier and quicker to make than a large one
When two parts are slightly different, a complete graphical representation of both parts is not required. Use the note:
SAME AS EXCEPT …
OTHERWISE SAME AS …

21. Simplifying the Design Process
Drawings made to modify stock parts should be as plain as possible. Avoid detail.
Use standard abbreviations whenever possible.
Whenever necessary, enlarge small details on larger parts for clarity.
Draw small parts large enough to avoid crowding so they may be easy to read

22. Simplifying the Design Process
Use standard symbols to represent common objects
Eliminate repetitive data by use of notes
Do as much free-hand drawing as possible
Use geometric symbols instead of notes

23. Assembly Drawing
Assembly drawing shows how each component is positioned with respect to the others
General assembly
gives a general graphic description of the shape
Sectioned assembly
shows the hidden features and their interdependence
Installation or outline assembly
indicates how the parts, shown separated, are assembled
Pictorial assembly
usually isometric, indicates how the parts, shown separated, are assembled

24. General Assembly Drawing
Detail drawing of a automobile connecting rod

25. Sub-assembly Drawing Assembly drawing of a automobile connecting rod
Shows the relationship between parts in an assembly
Minimum number of views used
Here one view is enough to show the relationship
This is also called a sub-assembly because this forms a part of the bigger assembly

26. Sectional Assembly Drawing
To avoid hidden lines, sectioning is done to improve clarity
Assembly drawing of a Grinder
The purpose is relation ship between parts in assembly than individual shape.
Minimum number of views must be used.
Only two views are needed to show the relationship

27. Sectional Assembly Drawing
To distinguish parts, section lines are drawn in different directions
Change of angle (not 45°) may be done if needed
Thin materials like gaskets are shown as thick lines in section
Standard practice is not to section bolts, shafts, even though section lines pass through them

28. Outline Assembly Drawing
Made specifically to show how to install a machine
This is also called an installation assembly
It outline the relationships of exterior surfaces

29. Outline Assembly Drawing
In aircraft drafting, installation assembly gives complete information for placing details of sub-assemblies in their final positions

30. Pictorial Assembly Drawing
Shows how to install a machine
Isometric views show separated parts

31. Pictorial Assembly Drawing

32. Pictorial Assembly Drawing

33. Pictorial Assembly Drawing

34. Tabular Drawings One drawing serves for a range of sizes
Dimensions are replaced by letters and an accompany table lists the corresponding dimensions for a series of sizes
One drawing serves for a range of sizes
There is a risk that the table will be misread

35. Standardized Drawing Drawing is made without dimensions
To avoid misreading of tables as in tabular drawing yet simplify drawing process
Drawing is made without dimensions
Copied by any method
Dimensions filled accordingly
Drawing is not to scale (NTS)

36. Checklist for a Good Design
Is the drawing easy to read?
Are the part outlines distinct from dimension lines?
Is the lettering neat and clear?
Is all of the information on the drawing?
Will the drawing make a good print?
Have all the rules of standard drafting practices been followed?

37. Checklist for a Good Design
Is the nomenclature correct? Will everyone understand it the same way?
Is the drawing title truly descriptive?
Are all the necessary views given?
Are all the dimensions shown?
Is there double dimensioning?
Are all the notes properly located?
Could any of the notes be misunderstood?

38. Checklist for a Good Design
Do the parts agree with the part list?
Are the standard parts specified correctly?
Is the scale designated?
Are the finishes specified in the drawing?
Is a heat treatment recommended?
Have standard manufacturing processes been followed?
Can the part be produced simpler and more economically?

39. Checklist for a Good Design
Are the materials specified?
Are the standard parts used as much as possible?
Are the suppliers for the standard parts indicated?
The design is yours. Are you ready to approve it?

40. Technical Data Presentation
Technical communication requires enhanced ways to convey data and numerical information

41. Encoding Data and Markers

42. Plots
2 D - scatter plot
2 D – connected line plot

43. Plots Regression line graph Mean and standard deviation
Mean and standard error

44. Plots
Bar graph (horizontal)
Composite bar graph

45. Plots