ESI 4554 ISE Systems Design Fall 2003 The Design Process ESI 4554 ISE Systems Design Fall 2003

The Design Process Definition #1: “The Design Process is the method of devising innovative solutions to problems that will result in a new product or system.” (Earle) Engineering design is more complex than identifying a need and devising a solution. Engineers need to work with budget restrictions, material shortages, interfacing with other systems while making the deadlines.

Types of Design Problems There are basically two categories: Product design: Involves the creation, testing and manufacture of an object that will usually be mass-produced. Design must meet a need and function independently to warrant its mass production. Factors that affect product design include market needs, function, production, costs, distribution, sales, and profit. Systems design: Arranges products, elements and components, providing a method for their operation.

Examples A car is a product because it is mass produced for the consumer market and can be purchased as a unit. It is also a system because it is made of several products which work together. An electrical power distribution grid is a system because it generates and distributes power to customers. A web-based customer service system that interacts with a customer and addresses his/her needs like, transferring money between accounts.

The Design Process (Earle) There are six basic steps to this design process methodology. Problem Identification (definition) Preliminary Ideas Problem Refinement Analysis Evaluation & Decision Implementation

A. Problem Identification First and most important step to solve problem: Understanding the problem! Most problems are not clearly defined at the beginning. Usually additional data is required, including problem background, causes, effects, needs, etc. Recognize a need (by observation of problem in product or system). Propose design criteria (propose specifications or design criteria that product or system must meet).

The Problem Identification Process 1. Problem Statement: describe problem in clear terms. 2. Problem Requirements: List conditions/specs that design must meet. 3. Problem Limitations: What affects the specs. (Size, weight, cost, color, performance). 4. Sketches: use engineering paper to record design ideas. Purpose: to document thinking process, avoid overlooking concepts, can help establish ownership of patentable ideas. 5. Data Collection: Record parameters for design, conditions it must meet.

B. Preliminary Ideas Goal: to develop as many ideas for the solution as possible. Brainstorming method collects ideas regardless of how extreme they may be.

Preliminary Ideas Individual vs Team Approach Individual must capture as many ideas as possible. Better ideas come from long lists than short lists. Teams: usually a moderator or team leader is designated to coordinate ideas, compare solutions and go back to the drawing board to come up with revamped ideas.

Methods for Gathering Preliminary Ideas Brainstorming: technique in which a group spontaneously contributes ideas. Rules: - No criticism allowed. - Wild ideas welcome. - Put up as many ideas as possible. - Combination and improvements are welcome.

Methods for Gathering Preliminary Ideas Obtain background on similar designs / systems: Purpose: To collect as much information on the product at hand or on similar products to facilitate the design process. Some Places to Research: Technical Magazines / Journals General Magazines Patents Consultants Surveys Internet

While Gathering Preliminary Ideas Sketching and Notes Purpose: To allow designer’s ideas to take form as three dimensional pictorials or 2D views. Notes are used to document functionality issues, materials, devices, etc. They are equally applicable to non-physical designs like data systems.

C. Idea Refinement Purpose: Give thought to functionality and practicality. Rank the best ideas to evaluate feasibility. Can use scale drawings of sketches produced in step B to evaluate idea merits.

D. Analysis Definition The evaluation of a proposed design by objective thinking and the application of technology. Intense evaluation of ideas to compare feasibility between candidates using engineering and scientific principles. Comparison can be based on cost, strength, function, market potential, etc. The design criteria establishes part of the comparison factors.

Types of Analysis Physical Specifications Analysis (in the case of a product). Look at lengths, areas, shapes. Determine: areas volumes capacities operating ranges packing / shipping / handling requirements.

Types of Analysis In the case of a System ? Material handling system. Production System Information System

Types of Analysis Functional Analysis Human Engineering Analysis: Most important. If it does not work, it is a failure. Human Engineering Analysis: Designer must consider physical, mental, safety and emotional needs of the user. Ergonomics comes into play. Designer should look at design dimensions and ranges to interact with comfort zones of people. Factors include dimensions, motion ranges, vision, sound, working environment.

Types of Analysis Strength Analysis: Finite element and real testing of components. Economic Analysis: itemizing of components involved, comparative pricing, other. Model (Prototype) Analysis: helps analyze design in final stages of development.

Conceptual models Rough models: used to analyze preliminary design or feature concept. Mock-ups: full-size dummies of finished design to demonstrate size, appearance, component relationships. Prototypes: Full-size working models to demonstrate operation of final product. Cheap materials are used at first to fabricate prototype instead of those used in the final product. Can use techniques like stereolithography and fused deposition rapid prototyping to produce quick versions of models to illustrate functionality and size.

Conceptual models Layout: Detailed scale models to show relationship between components of large systems, buildings, etc. Model Testing: Test models are used to determine how well a design meets requirements. Physical relationships and the functional workings are tested. Also used to test consumer reactions.

E. Evaluation & Decision Select best idea. Idea may be a compromise or even a combination of preliminary ideas.

Presentation, Evaluation, & Decision Presentation Objectives: to present findings of a project so a decision can be made whether to implement it. Three outcomes: acceptance, rejection, compromise.

F. Implementation. Describe design in detail with engineering drawings and specs. All drawings must be sufficiently explicit for the workers manufacturing the product and to serve as a legal contract with the successful bidder of the job.

Implementation Final step of design process: Working Drawings: Design becomes reality. Working Drawings: Used to specify fabrication specs., notes and methods. Ensure resulting product will be identical when instructions on the drawing are followed, regardless of the shop in which they are made.

Implementation Specifications Notes or instructions that supplement information shown in the drawing. Assembly Drawings - Illustrate how individual parts are put together to become the final product; can be 3D pictorials, orthographic views fully assembled, fully exploded or partially exploded. Other factors to consider: Packaging, storage, shipping, marketing.

Summary of Product Design Approach A. Problem Identification B. Preliminary Ideas C. Problem Refinement D. Analysis E. Evaluation & Decision F. Implementation

The Design Process Often we think as design as Product Development  “Product Development is the set of activities beginning with: the perception of a market opportunity and ending in the production, sale and delivery of a product”. (Ulrich).

Product Development Product Development usually has the following stages & considerations:   Phase Activity 0 (Product) Planning 1 Concept Development Identifying Customer Needs Product Specification Preliminary Concept Generation Concept Evaluation and Selection

Product Development Product Development usually has the following stages & considerations:   Phase Activity 2 System-Level Design Product Architecture Industrial Design Activities 3 Detailed Design Design for Manufacturing Prototyping

Product Development Product Development usually has the following stages & considerations:   Phase Activity 4 Testing and Refinement 5 Production Ramp Up while continuously thinking about Economics and efficient Project Management.

The Design Process according to ABET “It is a decision-making process (often iterative), in which the basic sciences and mathematics and engineering sciences are applied to convert resources optimally to meet a stated criteria.”

The Design Process according to ABET Fundamental Elements: - Establishment of Objectives and Criteria - Synthesis - Analysis - Construction - Testing - Evaluation

The Design Process according to ABET Features of a Design Project Must be creative address an open-ended problem use of modern design theory/technology format design problem statement design specifications, realistic constraints and assumptions

The Design Process according to ABET Features of a Design Project alternative solutions (consideration and feasibility) production processes concurrent engineering design detailed description of final design include aspects such as economics, safety, reliability, aesthetics, ethics, social impact.

What will be required for your Project: 1. Company Background Understanding of the company’s business, history and operations. 2. Problem Background After meeting and interviewing extensively with appropriate personnel, you will have enough background to understand the problem and fully establish #3. 3. Problem Definition / Statement A short, concise, to the point statement that defines the objective of the project.

What will be required for your Project: Example: “Design an automatic system that will identify, sort and transport packages from Building A to the company’s 3 loading areas in Building B with minimal human intervention. The system is must be able to handle any packages typically accepted by the company.”

What will be required for your Project: 4. Design Scope, Specifications, Constraints and Assumptions It is here where the scope of the problem is defined. System behavior and performance parameters are specified, as well as operating parameters, conditions, loads, capabilities, etc. and any other specific information related to the design of the system are stated. Constraints and assumptions that provide the basis for the system boundary conditions are determined.

What will be required for your Project: Example: The system must handle package weights up to 250 lbs. Box sizes are limited to those normally handled by the company and should not exceed L + W + H = 160 inches. System must also handle other shaped packages like cylindrical tubes, triangular tubes, letter-sized packages and envelopes. The system must be able to transfer packages from Building A to the loading dock at a minimum rate of 500 packages per hour, etc. etc.

What will be required for your Project: 5. Generation and Discussion of Preliminary Ideas This process involves discussion and brainstorming within the design team to produce idea that will transform themselves into potential design alternatives. 6. Idea Refinement and Generation of Alternatives. The team will produce three feasible alternative solutions to the problem. They are to be fully documented in terms of their design specifications, operation, etc.

What will be required for your Project: Final Alternative Selection At this point a comparison, validation and metrics factors are needed to evaluate the design alternatives side by side. Establish a table and the weigh the factors; this will help provide a ranking that will aid in the selection process. In the case of the material handling system, these factors include size, weight, cost, capacity, speed, controller type, maintainability, reliability, etc.

What will be required for your Project: Final Alternative Selection The final selection will then be fully justified, explaining why the choice is best suited for as the solution for the problem. A detailed description of the final design is developed at this stage.

What will be required for your Project: Validation & Metrics This stage is used to validate your design. In other words, how well does your design meet the design criteria. The system will have to be implemented or a prototype / simulation done to partially test its performance. You will need to benchmark your system to ensure that it not only meets the design criteria, but how well does it perform compared to other systems/alternatives.