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design process
- Not one process, many processes which have common
- characteristics
- Start off uncertain, don’t know exactly what final product
- will look like
As you continue, final product becomes more and more evident
- It is good to go outside of comfort zone (e.g. mech. eng.
- doing chem.)
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8 steps in design process
- Problem Identification,
- Idea Generation,
- Idea Selection,
- Detailed Design,
- Design Validation,
- Implementation,
- End of Life
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RussianDolls:
- Problems within problems, processes within processes, not evident in the
- beginning
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Problem Identification
- Make sure you are solving the correct problem, be aware of
- what you are actually aiming to do
This allows to find a more efficient solution
- E.g. Hotel Elevator: Slow elevators, instead of speeding them
- up they just added mirrors (pass time)
- junior engineers: … sometimes not your role to change
- problem?
Good engineers do start off a little uncertain/confused
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Opportunity Identification
In contrast, not always a problem, sometimes you have an innovative idea (IPAD)
- After you have identified the problem/opportunity, information gathering is
- important
- Figure out what kind of words people in that field use, get
- to know users, other solutions to the same problem someone else might have,
- file a patent
After problem identification, make objectives (long and short term)
- Scope: How far and deep you plan to go, how much impact will
- your idea provide
- Identify what you are NOT going to do, don’t want to solve
- all problems at the same time
To do this, you need constraints
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Constraints
Hard Constraints: Legal, by law things you must follow
- Soft Constraints: Still constraints because you decided you
- MUST have it
- They should be well
- written and should be able to be assessed pass/fail, yes/no
- ALL constraints must be satisfied for your project to be
- complete, for your solution to be acceptable
- Over constrained: Constraints that oppose each other (E.g.
- building must be taller than 6 feet but shorter than 5 feet)
- May be less obvious, but basically things that are near
- impossible to do together
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Criteria:
- similar to constraint, things you want to include in your
- final solution/product
- But they are not necessary, and only even think about them
- if your constraint is met
- E.g. our car should be fast (criteria), but the priority is
- for it to even work (constraint)
Criteria is measured, you want to maximize or minimize it
- Criteria often controls the decision made, because all
- solutions are going to satisfy constraints
- You want a balance among criteria, and remember importance
- of one criteria vs. another
- E.g. speed vs. looks, which is more important to you/to the
- overall goal of the item
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Idea Generation
- This is a very preliminary step, design with an extremely open mind here
- There is more than one solution to any problem, find them, choose best one
- Transportation A to B (Many options, walk, run, drive)
- Communication (Talk, text, email, etc.)
- Techniques for idea generation, brainstorming
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Feasibility
- First filter stage, first check which ideas even meet the constraints
- Try and pick best candidates to minimize analysis effort (which requires time + money)
- *Most innovative ideas usually get lost here, need to use experience and open mindedness to judge
- Make sure good ideas don’t get thrown out at this stage
- This is the least depth of analysis, but perhaps most important, most judgement required here
- After the feasibility you should have a few ideas left
- One is too few (too many constraints or not enough effort on idea stage)
- A lot is too much (use another filtration process)
- 90% decisions, 90% cost quote slide ?
- Not only decision stages, decisions are happening all the time
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Idea Development
- Consists of 3 main things:
- Multiple, parallel (happening at same time) activities complimenting each other
- Analysis of all the parts of the idea, synthesizing and pulling them all together into one solution
- Virtual and physical prototyping, calculations/computer simulations (solid works) and prototypes, scale models
- Find things that are right/wrong about the different ideas, further analyze and decide which are best
- Synthesize, put best ideas into one solution
- *Challenges: Hard to do an analysis for ALL ideas you initially had, this is why filteration process/feasibility is so important
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Preliminary Design
- Ideas at this point are pretty raw, start putting another layer of effort/detail
- Main goal here is to decide upon best idea and move forward
- Very decision driven, try to differentiate one idea from another
- Performance vs. criteria, may want to start relating back to constraints again
- enough depth slide??
- Also figure out budget in a little more detail
- initial Budget estimation: capital cost (estimate big main parts), operation costs (estimate what it'll take to keep it running), end of life cost (what is going to cost to remove/dispose)
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Decision Making/DESIGN VALIDATION (OCCURS SORT OF IN BOTH)
- Pretty much continuous throughout prelim design and idea development
- Usually very informal and subjective
- When making formal/important decisions, you want to be objective, third person point of view
- Perhaps use decision matrix (use weighted criteria, score out of 10, choose best one statistically)
- *Make sure weighting isn't subjective (don’t weight speed most because you like speed), look at it all objectively, what is most important to solving solution/problem, remember purpose of object
- Final decision: Don’t just trust decision matrix, look at results (maybe there are two close solutions)
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Detailed Design/ Design Validation
- At this point you have one idea, but this idea can continue to evolve and grow and be shaped
- Now you can afford to invest a lot more time and money
- Work out all of the details (e.g. specifications, exact size, number of nuts and screws, etc)
- It should theoretically be able to be built at this point
- This one final chosen design should make complete and total sense with respect to the constraints
- Its contribution to all the criteria is evident
- It is the best that it can be, does not have to be perfect obviously
- LOT S of virtual/physical design effort should be put in at this point
- Engineering models, 3D sketches, equations of the system/product
- Create prototypes, full scale if possible, run crash tests, make sure it is user proof
- "optimization", maximize/minimize what you want
- heuristic optimization ?
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Implementation
- Manufacturing, make sure it is going to be built how you designed it
- Process and buildings, be ready for errors and challenges that arise at this point, surprises
- E.g. There are alpha and beta trials with all software, but bugs and problems persist
- Recalls are sometimes a solution to this
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End of Life
- Waste, how will you deal with it
- What are the costs of disposal, what will it cost you, is environment a concern
- Next version designs, now you see strengths and weaknesses of the product (large scale trial and error)
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