1. The Engineering Design “Recipe”

2. Engineering Design Recipe Although the design process is very structured, it should not inhibit creativity! Looping and iterations are common! Separates “designing” from trial and error

3. Engineering Design… …is problem solving! Problem: My cell phone battery is dead Problem: I agreed to attend two different meetings during the lunch hour Define the problem, generate ideas, select a solution….but no building or evaluating Problem: “Design” a way to conveniently and effectively roll up the rim to win.

4. Problem Definition Ask questions! Ask questions as if you were the user AND the designer User: will it fit in my pocket? Designer: what kind of material will it be made of? First brainstorming session should be to come up with questions to better clarify the problem How big can it be? Does it have to work on a full cup? What type of people will be using it? What does ‘convenient’ mean? What does ‘effectively’ mean? How much should it cost?

5. Problem Definition Clarify objectives! Objectives of a design are Goals you work toward What the design “should” be “The design should be easy to use” “The design should be inexpensive” Design options may meet an objective perfectly, or they might only meet an objective part way

6. Problem Definition Establish constraints! Constraints of a design are Strictures or limitations on the design What the design must be The design must cost less than $500 to purchase The design must be able to carry at least 500 g of sand Must be able to answer yes/no The design must be lightweight  not a constraint The design must weigh less than 10 kg  constraint

7. Listing Objectives and Constraints Easy to use Lightweight Portable (fit in your pocket) Safe (no sharp edges or open cutting surfaces) Made of non-toxic materials Able to open enough of the rim to read the printed words Able to open the rim without mangling the cup objective constraint objective constraint objective A method of rolling up the rim should be…

8. Ordering Objectives Different designs result from the same problem “Design a device that enables people to reach heights they would be otherwise unable to reach”

9. Final design will depend on which objectives are MOST important Objectives: Portable Inexpensive Aesthetically pleasing Durable Safe for people of all ages Wide variety of uses Ordering Objectives

10. Pairwise Comparison Chart PortableInexpensiveAesthetically pleasing DurableSafe for people of all ages Wide variety of uses Score Portable X101013 Inexpen sive 0X00000 Aestheti cally pleasing 11X0002 Durable 011X013 Safe for people of all ages 1111X15 Wide variety of uses 01100X2

11. Measuring how well objectives are met (metrics) Constraints are yes/no so they are either met or they aren’t Objectives may be met part way  need to assign a “number” value Metrics: a scale that the designers agree upon to measure how well design alternatives meet objectives Should be unambiguous Should actually measure what you want to measure Should be repeatable

12. Metrics Metric scales can be based on actual numbers Objective: inexpensive to buy Metric scale < $500 scores a 10 >$1000 scores a 1 Metric scales can be subjective Objective: safe to use Likely to harm self or others scores a 1 Impossible to harm self or others scores a 10 Metric scales can be based on actual lab tests Objective: durable in all types of weather Lab test: build a scale model or prototype and subject it to simulated wind, rain etc. and assess the damage after a specific amount of time Total destruction scores a 1 Totally intact scores a 10

13. Applying Metrics A method of rolling up the rim objectives Easy to use Safe Opens enough of rim to read words Doesn’t mangle cup

14. Applying Metrics Metric for “easy to use” Requires extensive training  0 Requires one demonstration  5 Intuitive  10 Metric for “safe” Likely to harm self or others  0 Possible to harm self or others  5 Impossible to harm self or others  10 Metric for “opens enough of rim” <1 cm  0 1-3 cm  5 >3 cm  10 Metric for “doesn’t mangle” Words are indistinguishable  0 Words can be made out  5 Words are clear  10

15. Finishing Defining the Problem When you run out of questions, you can continue gathering information by searching literature “State of the art” searches  how do similar designs work? Web searches, patents, vendor information Expert information  talk to someone with experience in the area Sometimes more efficient than wading through documents Visual brainstorming  looking at images related to your design problem can stimulate thought process Google images, magazines, Science TV

16. Next Stage: Generate Ideas Literature searches can stimulate creative ideas Identifying functions and means can also help start the creative process

17. Functions Establish Functions! Functions of a design are Things the design will do Usually characterized with a verb-noun pair The design will support a load The design will dampen oscillation The design will contain liquid Try not to worry about how you will achieve the function yet

18. Help with establishing functions Imagine the object disappearing Imagine if a bookshelf wasn’t there, what would happen? The books would all be on the floor in a big heap! Function: support books Secondary function: organize books Think of the object as a black box and examine inputs and outputs The inputs on a radio are: channel/volume selection, power, and a radio frequency signal. Outputs include: sound, indicator lights and heat. Function: convert signal to sound Secondary (unwanted) function: generate heat

19. Morphological Charts Brainstorm ways to achieve functions and features Feature or function Means Cut rimScissorsKnifeLaser Razor blade Teeth Unroll rim Squeeze and pull Heating to expansion Momentum Wedge and slide Non-toxic material PlasticCardboardMetalGlassWoodNylon PortableKey chainZipper pull Attached to cell phone Part of your body

20. More on Brainstorming Need a specific problem statement How can we achieve this function? How is this function achieved in other situations? How can we meet this objective perfectly? Anything goes! Do not discuss until after session. Write everything down! Linking seemingly unrelated things is key to good brainstorming

21. Establish Design Alternatives Choose from your options in the morphological chart and use some creativity to put them together A method of rolling up the rim design options Fingers/teeth Knife/fingers Plastic RimRoller

22. Next Stage: Select a Solution A good solution must fulfill requirements, meet with deadline, and be produced with available resources.

23. Applying Metrics Easy to use SafeOpens enough Doesn’t mangle Score Fingers & teeth 691521 Knife & fingers 5210 27 Rim Roller 5105 30 Doesn’t account for relative importance of objectives!

24. Decision Matrices First, check to see if alternatives meet all constraints Constraints: portable (fit in pocket) and made of non-toxic materials Alternatives that meet all constraints can be entered into a decision matrix Decision matrices involve weighted objectives

25. Pairwise Comparison Chart (again) Easy to useSafeOpens enoughDoesn’t MangleScore Easy to use X0101 Safe 1X113 Opens enough 00X00 Doesn’t mangle 101X2 Apply weightings (subjective, discuss with group). Total weighting should add up to 100%. Safe: 40% Doesn’t mangle: 30% Easy to use: 20% Opens enough: 10%

26. Decision Matrix (with weighted objectives) Fingers & teethKnife & fingersRim Roller ObjectivesWeightScore Weighted Score Score Weighted Score Score Weighted Score Easy to use 20%61.251.05 Safe40%93.620.8104.0 Opens enough 10%10.1101.050.5 Doesn’t mangle 30%51.5103.0103.0 TOTAL100%6.45.88.5

27. Establish Design Specifications Specify Materials Sizes Types of motors Sizes of pumps Methods of attachment Size of holes Etc, etc, etc.

28. Next Stage: Build the Design! After all the question asking, brainstorming and evaluating, you should have a good idea of how the components will go together.

29. Next Stage: Evaluate! Test the design in conditions similar to actual conditions. Modifications may be required, or alternatives not previously considered may become obvious!

30. Final Stage: Communication Written and oral reports Written and oral reports Include all options as well as final option to show thought process and consideration for all alternatives Include all options as well as final option to show thought process and consideration for all alternatives Clear, concise, to the point, well organized Clear, concise, to the point, well organized

31. Working in Groups Engineering is multi-disciplinary! Communication is key Dealing with conflict Avoidance Smoothing Forcing Compromise Constructive engagement – the only way to consistently get “win-win” results

32. Making a plan and sticking to it! Procrastination can lead to stress and sub-par designs! Be aware of tasks that can overlap and tasks that must be completed before moving on Set deadlines for tasks, assign them to group members, and stick to the plan! Gantt Charts are visual representations of task breakdown, overlaps, and critical path

33. Sample Gantt Chart

34. Summary Ingredients: Brainstorming, objectives, constraints, functions Pairwise comparison charts, metrics, decision matrices, morphological charts Project planning, communication, creativity, patience