Reverse Engineering

1. Reverse Engineering Establishing Product Functions

2. Learning Objectives • Understand the concept of functional analysis and its role in the design process • Use a “Subtract and Operate” procedure to develop a function tree for ….. • Use the function tree to develop a Function Structure diagram for ……

3. Reading • Required Reading • Chapter 9 • Establishing Product Functions handout • Suggested reading • Appendix A - Function Structure Definitions handout • Subtract & Operate handout

4. Functional Modeling and Analysis • Functional analysis is an integral part of product design and re-design: • A way of structuring your thinking about the problem • A way of aiding Product Design Specifications development • Can also aid in concept generation

5. Generating Concepts Define Customer Requirements Product Function(s) Model and Analyze Function Brainstorming / Directed Search / Inventive Problem Solving Identify Functional Solutions + + + + F1 F2 F3 F4 F5 6 Formulate Candidate System Solutions OR OR S1 S2 S3

6. Verify Functions Against Needs

7. Functional Analysis... • Identifies important systemcomponents and their functions. • Describes how these components functionally interact with each other and super- and sub-systems. • Clarifies the best problem to solve.

8. Functional Analysis/Modeling • There are several methods for Functional Analysis • Product Function (Top-Down) --- Dissection • FAST (Functional Analysis System Technique) (Top-Down) • Subtract and Operate Procedure (Bottom-Up) --- Dissection

9. Functional Modeling Basics Product Function – What the product does. A statement of relationship between available input and desired output, independent of any particular form. (Overall Function) Chop Beans Transport People Accept Human Chopper Vehicle Door System

10. Functional Modeling Basics Product Sub-function – A component of product function. The combined effect of two or more product sub-functions is product function. • Example: Hold Liquid • Contains liquid • Insulates liquid • Insulates hand • Supports liquid • Accepts pour • Interfaces hand • Pours out

11. A System... • Is an entity that is connected to its environment bymeans of inputs and outputs defined on its boundary, • It can be defined in terms of mechanical construction (form) or by function, and • It can be decomposed into Sub-systemsconnected to each other by means of inputs and outputs defined on their respective boundaries. Inputs System Outputs Input 1 Output 1 Input 2 Output 2 Input 3 Output 3

12. Functions Functions should be expressed in terms of measurable effects Typical function expression: “active verb – noun” “increase pressure” “transfer torque” “store energy” “cool liquid”

13. Some functions that products/parts perform Refer to Appendix A - Function Structure Definitions handout for detailed description of functions.

14. State 1 State 2 Energy Energy Function Material Material Signal Signal Function & Flows All product activities involve changing the state of three basic quantities: energy, material and signal. We call this change of state a “flow”.

15. Form  Function  Flow Form Water Heater Hot Water Cold Water Function Electric Current R Flow Cold Water Hot Water Heats Water Electric Current

16. Is “Low Price” a function?

17. Functions vs. Goals vs. Constraints • Functions represent what the product does to satisfy the customer need. • Some customer needs are satisfied by how the product is implemented in form. These are attributes or features of the product. • Criteria can be attributes on one product but functions on another. • Example: Storage compactnessAttribute : Small sizeFunctional Solution: Make it fold up • When in doubt: If the criteria is met by an identifiable sub-system doing something, then it is a function; otherwise, it is an attribute.

18. Subtract and Operate Procedure • Disassemble (subtract) one component of the assembly. • Operate the system through its full range. • Analyze the effect. • Deduce the subfunction of the missing component. • Replace the component and repeat n times where n is the number of components in the assembly. • Translate the collection of subfunctions into a function tree.

19. Example: Coffee Grinder Chamber Slicing blade Seal Energy System Operator Grinder Ground Coffee Coffee Beans

20. Elements for Subtraction with Results

21. Function Tree The Subtract and Operate procedure helps us determine the critical functions and subfunctions of our device. These can be mapped to a function tree similar to figure 5.6 from Otto and Wood.

22. Steps in Creating a Function Structure • Identify the overall function. In our case, this is the top block in the function tree. • Identify the basic individual functions that are required to accomplish this task. We have already done this in the first row of functions of the Function Tree. • Identify more precise functions from the basic functions determined in the previous step. Note that these two steps will be iterative. These more precise functions are the second level of blocks in the Function Tree. • Arrange the function blocks in the order that they must occur to accomplish the desired overall function. This is a flow chart of functions in which order is important. The easiest way for us to do this is to take the 3x5 cards we used to make the function tree and place them in position until the group is satisfied. • Add the energy, material, and signal flows between the function blocks as appropriate. • Double check to make sure you haven’t missed a function block or flow line. • Reproduce the function diagram electronically.

23. Function Structure Thick arrows: material flow Thin arrows: energy flow

24. Where to go from here? • SOP for flash light • Generate SOP table • Generate function tree • Generate function structure • All of this is due next Monday

25. Activity for Today Apply SOP on flashlight / spot light you have

26. 1. Case -A very thin spring or strip of metal (usually copper or brass) that is located throughout the flashlight, making the electrical connection between the various parts – the batteries, the lamp and the switch. These parts conduct electricity and “hook everything up”, completing the circuit. • 2. Contacts -Deeper grooves for easier hold. • 3. Switch -The flow of electricity is activated when you push the switch into the ON position, giving you light. The flow of electricity is broken when the switch is pushed into the OFF position, thus turning off the light. • 4. Reflector -A plastic part, coated with a shiny aluminum layer that rests around the lamp (bulb, LED) and redirects the light rays from the lamp to allow a steady light beam, which is the light you see emitting from the flashlight. • 5. Lamp -The light source in a flashlight. In most flashlights, the lamp is either a tungsten filament (incandescent bulb) or a light emitting diode (solid state bulb), also known as an LED. The lamp glows when electricity flows through it, thus producing visible light. Incandescent bulb must be replaced when the tungsten filament breaks. An LED contains a very small semiconductor (diode) that is encapsulated in epoxy. LEDsin flashlights are widely considered “unbreakable” – a lifetime lamp. • 6. Lens- Clear, plastic part you see on the front of the flashlight that protects the lamp. • 7. Batteries- When activated, batteries are the power source for your flashlight. http://www.energizer.eu/eu/ee/site/how-flashlights-work.html