DESIGN 1 DPT224 Topic 3: Formulating Design Problems

Objectives  At the end of this topic, students should be able to: Define design problems/ needs Develop an objective tree from the design’s need Identify product anatomy

Design Problems/ Needs  Starting point of design projects is the identification of a client’s need  Client’s need is often presented as a verbal statement Client’s A gadget that will attract certain markets:  Ex: Portable MP3 player A product that will perform specific functions  Ex: Battery operated portable screw driver A product that will solve a problem through new design  Ex:

Design Problems/ Need There are several characteristics that differentiate one design problem from another:  Design problems involve improvements to existing product. Ex: Lower-cost car seat. Our customer, a leading automobile manufacturer, has contacted our company to lower the total cost of a line passenger seats that we make for them. What compromises will our customer be willing to make? Cost for comfort? Cost for safety?

Design Problems/ Need  Development of a new product, something that never exist. Ex: Clothes folding machine. The CEO of our company has requested the R&D department to design and manufacture a new automatic clothes folding machine. For a trial run, only six units to be produced, what manufacturing processes that would be economical?

Design Problems/ Needs  Design problems involve relatively simple, one-piece products. Ex: Toothpick or hockey stick. Shaped from a single material.  Design problems involve a very complex products. Ex: Automobile, army tanks and commercial jet airplane. That include thousands of components made with different materials or manufacturing processes.

Objectives tree  Important to clarify the design problems & objectives  Procedures: 1. Prepare a list of design objectives 2. Order the list into sets of higher level and lower level objectives 3. Draw the tree of objectives, showing the hierarchical relationships and interconnections

Objectives Tree  Objectives: The desired attributes of a design  Example: High Performance  Constraints: Limitation of a design that is acceptable

Example  Design a water purifier for Gotham City  Build an objective tree

Example  Water purifier  1. List of design objectives: Cost effectiveness Can detect chemical imbalance Fewer repairs Easy to repair when needed Long lasting Affordable Low or no contamination Takes up least possible space Safe for humans Safe for environment Low maintenance Cleans high volume of water Efficient …… ………

Example  2. Order the list into sets/ groups:  Safety Safe for humans Safe for environment  Cost effectiveness Few repairs Easy to repair Affordable Takes least possible space Low maintenance

Example  Efficiency Can detect chemicals Long lasting Low damage Clean high volume of water

Example

fig_03_02

Product Anatomy  Product are made of one or more fundamental components arranged in structure assemblies.  Products anatomy is like structures, (e.g.: like the parts and systems of the human body that work together.)

Product Anatomy  A product is an item that is purchased and used as a unit.  Some products are simple and others are complex depending on the number, type, and function of their components.  Example, the paper clip, canoe paddle, and toothpick are single-component products.  The penlight, bicycle, and toaster oven are somewhat more complex.  The refrigerator, automobile, and commercial jet airplane are very complex.

Table 2 lists a small portion of the many thousands of products manufactured each year.

Product Anatomy  Products are composed of components that include parts and assemblies.  A part is a single piece requiring no assembly, sometimes called piece-part.  An assembly is a collection of two or more parts or subassemblies.  A subassembly is an assembly that is incorporated into another assembly or subassembly.

Product Anatomy Product Sub-assembly A Standard Part Standard part Special purpose part Special purpose Part Sub-assembly B Special purpose part Sub-assembly B1 Standard part Special purpose part

Product Anatomy  A standard part is a common interchangeable item, having standard features, typically mass-produced, used in various applications. Exp.: screw, bolt, nut, washer, rivet, and gasket.  A special-purpose part is a part designed and manufactured for a specific custom application. Exp.: engine housing, control link, access cover, support bracket, and washing-machine tub.

Product Anatomy  A standard assembly or subassembly is one that is commonly sold and used in various applications. Exp.: electric motors, pumps brake calipers, ball bearings, valves, and electric switches. They are sometimes referred to as modules. Companies that use standard components purchased from one or more suppliers are called original equipment manufacturers, or OEMs.  A special-purpose assembly is an assembly that is designed for a specific application. Exp.: a garden tractor transmission that incorporates a custom housing, drive shafts, standard bearings and gears.

Examples of types of components

Product Anatomy  Process of categorizing the components of a product into parts and assemblies is called product-component decomposition.  It is useful during reverse engineering process when design team want to learn about each components of an existing competitive product

Example of decomposition Figure 1

Decomposition example  Looking at the assembly drawing from left to right, we see that the penlight is an assembly of a cap, bulb, battery, spring, button switch, and case.  The cap is special purpose part made specifically to hold the bulb. The bulb is a subassembly composed of a glass lens, filament, and base.  Since the bulb is mass-produced and made in standard sizes it is a standard subassembly. The spring is a part that is usually purchased as a standard part.  The special-purpose button part acts as a switch by pushing the battery toward the bulb to connect the circuit.  The battery is a standard subassembly including an anode, cathode, electrolyte paste, and plastic cover.  The metal case is a special-purpose part, cylindrical in shape and electrically conducting.

 A product component decomposition diagram is shown in Figure 1. Note that the diagramming scheme uses an oval to represent a product and rectangle for a subassembly.  Individual parts are shown as plain text. Also note that solid lines are used to show the hierarchy of the parts and subassemblies. Figure 6: Product component decomposition diagram of a penlight

Sekian terima kasih