TOPICS
- Graphics language in Engineering Design Process
- Computer-Aided Drafting & Design (CADD)
Graphics Language in Engineering Design Process
Lockhartet al.
“Design is the act of creating the specifications for a product or process that best satisfies the design criteria.
Bertoline et al.
“Design is the process of conceiving or inventing ideas and communicating those ideas to others in a form that is understood easily.”
What is “Engineering Design”?
Simplified Definition
Design Process
Needs solutions
- Write down the problem statement.
- Generate possible solutions.
-
Evaluate each solution against
the criteria and select the best one.
- Document the solution.
The Role of Graphics
Visualization
Communication
Documentation
Yesterday, I went to Civil department to buy a textbook.
I saw the window panels are very dirty.
Maybe, a person responsible to this job is lazy.
I don’t think so. I saw she worked diligently.
..…
I asked her, why don’t you clean those windows ? 
What did she answer you ?
She said it is impossible to clean those windows.
So, what do you think ?
I looked at the windows again, then I understood her answer.
What are your findings ?
I founded that the windows have two glass panels.
One is fixed to the top, another one is fixed to the bottom of a window frame.
Both panels place offset with each other and their
?
?
free edge overlap about mid of the window’s height.
Sorry, I cannot imagine about the window you have explained.
Okay, I will show you a sketch of the windows.
Visualization &
Communication
Sorry, I still do not understand why it is hard to clean the window.
The glass panel
is thin, so he omits
section lines !
Um.. . I will show you the side view of this window.
Ah.. I see. The offset distance is small, so she can not access the opposite side of the window and the
overlapped zone.
That is right !. If we do not solve this problem, learning environment will become worse and …….
Teamwork
Individual
- Hire a cleaning service company.
- Buy a usable device.
- Redesign the window construction.
-
Change the window to
concrete wall.
- Design a homemade cleaning device.
6. ………………………
|
Criteria | |||||
| Availability | Cost | Simplicity | Aesthetic | ||
|
Assume you (or your team) make a decision that
“Design a homemade cleaning device”
is the best solution under listed criteria.t
- Modify from an existing solution.
Solutions A, B …
- Ad hoc solutions.
Major functions of a device
- Wash & Polish (the panel)
- Wipe
Would you like to combine both functions into a single device ?
Yes
Single device.
No 1)
Two devices: One for wash & polish
another one for wipe.
Assume you (or your team) choose this choice.
2) Single device but has a changeable part.P 2 : Generate possible solutions.
Function
Wipe
What should be an appropriate form of part(s) to do the required functions?
Hold
(by user)
What material is the part should be made of ?
Easy to use. Should not rust.
How parts are assembled ?
Not too expensive.
Not too heavy.
Can insert between the panels.
Solutions
Criteria
Cost Weight
Size Ease of operation …
Assume you (or your team) choose the solution Cis used to represent rough ideas.
If this final results are unsatisfactory,
the selected solution will be modified.
Mathematical analysis
Computer simulation
Build and test a prototype Operation
STEP 4 : Document the solutions Documentation =
Write a technical report
ComputeCAided
Drafting & Design
Definition
Computer-aided drafting and design (CADD) is the computer process of making engineering drawings and technical documents more closely related to drafting.
Evolution of Engineering Drawing
Time
Brain
Pencil & Paper
Traditional tool 2-D CADD Solid modeling
Working Drawing
Interpret
by operator
Create machine code
by operator
Translate
part information to machine code
Process
Conventional machine
(manual operate)
aCNC machine
Drafting stage
Design stage
Advantages of CADD
- Increased accuracy
- Increased drawing speed
- Easy to revise
- Availability of drawing libraries
- Built-in several analysis tools
-
Better presentation (Easy to visualize)
– Pan, rotate, animate, shade, texture
CADD Capability
- Draw
- Modify
- Dimension
- Object snap
- Layer concept
- Draw
2-D CADD
Draw a group of lines that
are connected and present
- Orthographic multiview
- Pictorial view
Concepts in Working Drawing Creation
Solid modeling Draw a closed contour and convert to surface.
Modify this surface to
solid object.
Create an orthographic
view from a solid object.
Good engineering drawings must have the following characteristics.
Parts or product information is completely given. 
Information is clearly presented.
Information can be used in manufacturing of part.
To create a good engineering drawings YOU MUST
do the following tasks yourself.
- Apply a proper line weight and style.
- Select a necessary view.
- Decide the appropriate places of dimensions.
- Select an appropriate section techniques (if necessary)
(within scope of drawing interpretation)
Because they are frequently used technical document.
Therefore,YOU MUST prepare yourself for interpreting (or visualizing) them when you become ENGINEER.
No CADD software can create a pictorial view from an orthographic multiview.
What do you think ? Good or Poor
What do you think ? Good or Poor.
What do you think ? Good or Poor.
What do you think ? Good or Poor
What do you think ? Good or Poor
