Senior Design

1. Senior Design Fall 2005, Week 3 Notes are based on “Engineering Design and Design for Manufacturing – A Structured Approach” by John R. Dixon and Corrado Poli

2. Lecture Overview • Groups • Projects • Conceptual Design Overview • Formulating the problem • Customer Attributes • Engineering Characteristics • Engineering Design Specification

3. Group 1 (Energy 1 – project presented by Dr. Fletcher) Richelle Atienza Holman Chua Jason Garner Jason Harrington Joshua Severance Group 2 (ASME 1) William Berry Nicholas Fonder Jason Kardos James Martini Group 3 (Energy 2 – project to be discussed with Dr. Fletcher) Sean Mochocki Evan McNay Lince Philip Richard Thompson Stephen Thompson Group 4 (ASME 2) Justin Caudle Luke Delaney Joshua Isaacson Peter Vergenz Group 5 (Extruder – Project presented by Dr. Adewale or a modification to the project) Anthony Barletta Daniel Jones Parineeta Nayyar Spencer Schwab Groups

4. Engineering Conceptual Design • The Goal • Determine the physical concept of the designed object • Information about the physical principles by which the object will achieve its principal functions • An abstract physical description of the object called the embodiment • Embodiment: Abstract physical description with few details provided • Beam is long and slender member of uniform cross section but we don’t know the exact cross sectional shape or dimensions • The process of decomposition • Guided Iteration

5. The process of decomposition • It is necessary to “decompose” the design into more manageable sub-assemblies/components. • Helps in finding creative solutions and ultimately generating a superior design • Two primary approaches of conceptual decomposition are used • Direct decomposition • Function-First decomposition • Will need to include the couplings between subsystems • How are forces transferred? Energy transfer?

6. Direct Decomposition • A product is composed of the subsidiary components (the design is not really decomposed) • Ex: An automobile is decomposed into its engine, drive train, body, suspension system, steering system. • Then you work on each of the decomposed systems and find the best design for each. • This decomposition method minimizes creative new ideas.

7. Direct Decomposition continued • Often used by Mechanical Engineers • A sketch is commonly used identifying the embodiment • Ex: For a bicycle we would identify the handle bar (but for what function) • Ex: Design a breaking system for an automobile • Foot pedal, hydraulic system, and brake shoes and drums.

8. Function-First Decomposition • First the functions are identified without any embodiments assumed • Then embodiments are identified to fulfill the functional needs • This process often helps identify creative solutions • Abstract way of thinking.

9. Overview of Guided Iteration Applied to Engineering Conceptual Design • Formulating the Engineering Conceptual Deisgn Problem: The Engineering Design Specification • The Engineering Design Specification is used during the conceptual design stage and through the rest of the design stages. • Should be a written document • Convert the vague, qualitative, and incomplete information that is generally available at the beginning of the conceptual design stage into a set of specific, quantitative, complete performance requirements • Will use Quality Function Deployment (more to come…) • Ex: Should be easy to carry  the weight should be less than 20lb • Generating Alternatives in Engineering Conceptual Design Problems • The selection of the best possible conceptual design is crucial in obtaining the best possible final design solution. • Mistakes at the conceptual design stage are extremely costly if you must backtrack when in the configuration, parametric, and detailed design stages. • Evaluating Alternatives in Engineering Conceptual Design • Alternatives are rated and compared • Guided Redesign • Illuminate the specific characteristics of proposed alternatives that are weak and strong. • Is the design “good-enough”?

10. Summary of guided iteration methods (Engineering Conceptual Design)

11. Formulating the Problem: The Engineering Design Specification • Includes statements • In-use purposes, and • Functional requirements • Some information may be available from marketing and industrial design stage • Most information available at this stage is typically qualitative, incomplete, and/or approximate • The Engineering Design Specification will be used in future design stages so care should be put into making it as detailed and complete as possible.

12. Overview: Engineering Design Specification (Specs) • in-use purposes • Primary Purpose • Unintended Purpose • Special Purpose • Functional Requirements • Product performances • Functional Performance Requirements • Complementary Performance • Environmental and other conditions • Economic issues • Physical attributes • Process technologies • Aesthetics • Product development time and cost • Before developing the Specs it is best to understand the customer needs. • House of Quality

13. Quality Function Deployment (QFD) and the House of Quality (HoQ) • QFD: term used to describe a strategy for focusing engineering design attention on quality issues as perceived by customers • HoQ: A technique used for structuring information commonly used to implement QFD.

14. House of Quality • Matrix that relates the customers wants (Customer Attributes) to the technical product characteristics (Engineering Characteristics) • Customer Attributes (CA) • Generally qualitative • Fast, smooth, easy • The Customer Attributes are listed to the left of the rows (also grouped – functions, features) • Engineering Characteristics (EC) • Qualitative • Weight in pounds • The Engineering Characteristics are listed at the top of the columns (grouped by categories) • HoQ is also used for competitive benchmarking

15. House of Quality

16. Coffee Maker Example • Customer Attributes  Good coffee • Nice looking coffee maker • Easy to clean • Engineering Characteristics • Goodness of coffee (in measurable quantities) • Functional requirements • Temperature • Flow rate of water • Time the water takes to flow through the grounds • Temperature when poured into the cup • EC will include requirements such as the electrical resistance to the heater, the size of the tube supplying the hot water to the coffee grounds, and other factors having to do with geometry and materials. • Since there are yet no proposed designs there are no engineering characteristics yet. • Determine the Customer Attributes, then write the Specs and then return to the Engineering Characteristics

17. Customer Attributes Protects the discs Attractive Inexpensive Can identify the contents Stays closed Easy to open Can’t be used as a coaster for coffee cups Holds at least 6 CDs Doesn’t pop open on its own Won’t break if dropped Compact Eliminate redundancies Organize the list hierarchically Protects the discs Stays closed Won’t break if dropped Can’t be used as a coaster for coffee cups Convenient to use Easy to Open Ca identify the contents Compact Attractive Holds at least six CDs Inexpensive Often priorities are assigned to the customer attributes that total 100 units CD protective portable carrying case

18. Assignment of priorities • Stays closed 20 • Won’t break if dropped 14 • Can’t be used as a coaster for coffee cups 5 • Easy to Open 20 • Can identify the contents 10 • Compact 7 • Attractive 5 • Holds at least six CDs 7 • Inexpensive 10 Total100

19. Content of the Engineering Design Specification • Develop the Specs after the Customer Attributes have been identified • The Specs should include • In-use purposes • Functional Requirements

20. In-use purposes • Primary Intended Use By Customers • Examples • To make coffee • To convert electrical to rotating energy • To aid in the catching of a baseball and to protect the hand when doing so • Some products have multiple uses • Baseball glove example • Hammer: Drive and pull nails • Predictable Unintended Uses • Wrenches are used as hammers • Screw drivers as chisels • Shelves and chairs as step ladders • People standing (and jumping) on top of the washing machine • People driving with the windshield sun protector???? Remove when driving. UNF parking tag…. • NOT enough to use warnings. Must design with unintended uses in mind. Legal and common sense reasons. • Design the wrench such that it is reasonable safe to use as a hammer

21. In-use purposes • Special Purpose Features • Features that enhance the product • Rechargeable electric shaver that can be directly plugged into the outlet rather than having an inconvenient cord. • Redial button on your telephone • No-drip tops on laundry detergents • May rate the special purpose features as essential, important, or desirable

22. Functional Requirements • Product performances • Functional Performance Requirements • Capacity (energy or material flow rate, force, …) • Input and output conditions (temperature, energy, pressures, flows, power, deflections, forces) • Efficiency • Accuracy and sensitivity • Complementary Performance • Useful life • Reliability • Robustness • Safety • Noise • Legal requirements • Maintenance requirements • Requirements on users (skills, speed, knowledge, …)

23. Functional Requirements Continued • Environmental and other conditions • Temperature, humidity, corrosive elements, noise, dirt, vibration, electric or magnetic field. • Extremes of variations • How product will be disposed, how it will influence the environment, design for dis-assembly. • Is pollution a problem? • Economic issues • Tooling cost, initial product cost, maintenance costs, return on investment, cash flow, break even time • Physical attributes • Weight, size, shape, surface finish, … • Aesthetics • Style, uniqueness, … • Work with marketing team • Product development time and cost • Process technologies • restrictions on manufacturing processes

24. Expressing Functional Requirements • Qualitatively • Verbal statement (high, low, moderate, fast, slow, …) • As extremum goals, with or without limits • Mass should be as low as possible • Mass should be as low as possible but no higher than 10 lb • As target values with tolerance • The power output of an engine should be 5 Hp +/- 0.25 Hp • As ranges • Length must be between 3.7 and 4.8 inches

25. Completeness and Invariability of the Engineering Design • The Specs should never be though of as complete or invariable at any stage in the design process. • Specifications should be as complete as possible on what the designed object is to do. They should say as little as possible about how the requirements are to be met.

26. Example: A Portable Wind Chill Meter • In-purpose use • Primary Intended Use • For skiers and winter hikers: to be able to determine the so-called “wind chill” factor easily and conveniently • Unintended Uses: • Non anticipated • Special Features • Indicate temperature, wind velocity seperately as well as the combined wind chill

27. Example continued • Functional requirements • Performance requirements • Functional Performance requirements • Indicated reading should be accurate within one degree using U.S. Weather Bureau formula for the wind chill • The meter should provide a reading after no more than 20 seconds for reaching equilibrium with the outdoor environment • The meter should perform with the above accuracy from 32 F to 50 F, and from wind velocities from 10 mph to 60 mph. Accuracy should not be affected by mis-orientation with the wind direction up to 20 degree angle

28. Example continued • Functional requirements • Performance requirements • Complementary performance requirements: • The expected life in normal use should be at least 10 years • The reliability should be such that no more than one in 1000 sold will be returned for repairs or replacement during the 1st year of use. • Must be able to withstand shocks and pressure without damage when carried in jacket pockets • Hiker or skier should not be cut by the device if (s)he falls. • No maintenance should be required (except battery replacement – if used)

29. Example continued • Environmental conditions • Use at previously mentioned conditions • Survive summer shipping storage up to 120 F and 80% humidity • Economic issues • $10 (for a volume of 5000) • Physical Attributes • To be carried in a ski or hiking jacket pocket • No more than 16 oz • 3 x 5 x ¾ in3

30. Example continued • Process Technologies • None • Aesthetics • Should look like a rugged, reliable, accurate device compatible with the quality equipment needed by skiers and hikers • Product development time and cost • The product should be designed and prototyped by <specific date>. Design and development cost, including engineering , model shop, and laboratory should not exceed <specified amount>

31. Assignment for next week • Meet with your group • Define a project leader • Determine times when you will work on the project as a groups each week • At least 2 times (Beginning of the week discuss the tasks, split and work independently, regroup) • Define the Customer Attributes with priorities • Start discussing the Specs