Engineering Graphics & Models

Fall 2013

Lecture 1

Introduction to Graphics Communication

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Graphics Communication

• Visualizing, sketching, modeling, and detailing are how engineers and technologists communicate as they design new products and structures for our technological world.

Figure 1. Users of graphics

• In engineering, 92 percent of the design process is graphically based.

• Sharing technical information through graphical means is becoming more important as more nontechnical people become involved in the design/manufacturing process.

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Graphics in the Design Process

Technical graphics is a language used in the design process for:

• Visualization

• Communication

• Documentation

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Figure 1. Technical drawings are used to communicate complex technical information.

Visualization

• Visualization: ability to mentally picture things that do not exist.

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• Most designers will initially capture their mental images by sketching them on paper.

• Visualization and the resulting sketch is the first phase in the whole process of graphics being used in the design process.

Figure 2. Design sketch of a hand digitizing system

Communication

• Communication: you must be able to improve the clarity of your graphics to such an extent that others are able to visualize your design

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• In the past, real models of the design were created;

• many industries now use rendered 3-D computer models to replace real models.

Figure 3. A refined 3-D model of the digitizing system used to communicate the design without ambiguity

Documentation

• Documentation: you must be able to improve the clarity of your graphics to such an extent that others are able to visualize your design

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Figure 4. A detail drawing used in the documentation process

The Engineering Design Process

• Engineering design is associated with the entire business or enterprise, from receipt of the order or product idea, to maintenance of the product, and all stages between.

• Linear engineering design is a design approach divided into a number of steps

Figure 5. Traditional engineering design sequence

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The Engineering Design Process

• The model-centered engineering design process is a nonlinear team approach to design that brings together the input, processes, and output elements necessary to produce a product.

Figure 6. Model-centered engineering design

• Collaborative engineering is dependent on computer based tools, which are used to create a virtual representation of a product design.

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Figure 7. Collaborative engineering design

Virtual Product Representation

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• Collaborative engineering is highly dependent on computer based tools.

• These tools used to create a virtual representation of a product design through:

1. 3-D CAD models 2. Product Data Management 3. Large assembly visualizations 4. Packaging analysis 5. Tolerance analysis 6. Structural, thermal, and flow analyses 7. Dynamic simulations for design and manufacturing 8. Virtual Reality 9. Collaborative Web Technology

Virtual Product Representation

• Prototyping: quickly create a physical model of a part or functional prototypes to create mockups of the part suing traditional means

• Productivity tools: used by engineers and technicians on a daily basis to support the overall design process

• PDM/Configuration management: tools to manage long-term overall design/manufacture process

• Internet, Intranet, and Extranet: computer networks used to share information

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The Engineering Design Process

• Product Life Cycle Management (PLM): model that facilitates the simultaneous working of all the company’s departments: engineering, strategy, marketing and sales, planning and production, procurement, finance, and human resources.

Figure 8. Product life cycle management

• PLM is a strategic business approach for the effective management and use of corporate intellectual capital.

• PLM supports and enables three interconnected processes:

1. Supply chain collaboration 2. Product development 3. Enterprise process integration

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Design Projects

• The membership of a design team will vary according to the complexity and type of design.

Typical members of a design team might include:

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• Product design engineer • Product manager • Mechanical engineer • Electrical engineer • Manufacturing engineer • Software engineer

• Detailer/drafter • Materials engineer • Quality control engineer • Industrial designer • Vendor representatives

Types of Design Projects • Modification of an Existing Design • Improvement of an Existing Design • Development of a New Product

Ideation

• Ideation is a structured approach to thinking for the purpose of solving a problem.

Figure 9. Ideation process

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Ideation

Ideation is the start of the design phase and includes: • Problem identification – process in which the parameters of the design

project are set. Problem identification includes the following elements: Problem statement, Research, Data gathering, Objectives, Limitations, Scheduling.

• Preliminary ideas development – is the process of suggesting as many solutions to a problem as possible, brainstorming. It results in a list of ideas, along with some preliminary sketches or computer models.

• Preliminary design – creation of models out of foam or other material, or using computer models

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Refinement

• Refinement is a repetitive (iterative or cyclical) process used to test the preliminary design, make changes if necessary, and determine if the design meets the goals of the project

Figure 10. Refinement process

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Refinement

Figure 11. Refinement of a battery contact design

• The refinement stage begins with rough sketches and computer models to create dimensionally accurate drawings and models

• Then the engineers select the materials for the component parts

• The preliminary design is tested physically, the design is analyzed, and manufacturing begins to determine the processes needed to produce the product

• The preliminary design is also market tested to a small group

• The final step in the refinement stage is selection of the final design for the product

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Refinement

• Modeling is the process of representing abstract ideas, words, and forms, through the orderly use of simplified text and images. A descriptive model presents abstract ideas, products, or processes in a recognizable form. A mathematical model uses mathematical equations to represent system components. A scale model is a physical model created to represent system components.

• Computer simulation is the precise modeling of complex situations that involve a time element.

• Computer animation is the imprecise modeling of complex situations that involve a time element.

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Refinement: Design analysis

• Design analysis is the evaluation of a proposed design, based on the criteria established in the ideation phase Property analysis, which evaluates a design based on its physical

properties Mechanism analysis, which determines the motions and loads Functional analysis, which determines if the design does what it is

intended to do Human factors analysis, which evaluates a design to determine if the

product serves the needs of the consumer Aesthetic analysis, which evaluates a design based on its aesthetic

qualities Market analysis, which determines if the design meets the needs of the

consumer, based on the results of surveys or focus groups. Financial analysis, which determines if the price of the proposed design

will be in the projected price range set during the ideation phase.

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Implementation

• Implementation is the third and final phase in collaborative engineering design and is the process used to change the final design from an idea into a product, process, or structure.

Figure 12. Implementation process

It includes: • Planning • Production • Marketing • Finance • Management • Service • Documentation – process used to

formally record and communicate the final design solution

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Implementation

Planning: Manufacturing engineers and technologists are the leaders in the planning process, as they schedule the machines and jobs necessary to create the product.

• Modern planning techniques include computer-aided process planning (CAPP), material requirements planning (MRP), and just-in-time (JIT) scheduling.

Production: the process used to transform raw materials

into finished products and structures, using labor, equipment, capital, and facilities.

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Implementation

Marketing: anticipates customer needs and directs the flow of goods from the producer to the consumer

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Figure 13. Marketing process

Finance: analyzes the feasibility of producing a product, relative to capital requirements and return on investment

Implementation

Management is the logical organization of people, materials, energy, equipment, and procedures into work activities designed to produce a specified end result, such as a product.

Service is an activity that supports the installation, training, maintenance, and repair of a product or structure for the consumer.

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Figure 14. Production manager’s responsibilities

Documentation

Documentation – process used to formally record and communicate the final design solution

• Concurrent documentation is a process that creates documents at the same time that the product design is being developed.

Figure 15. Concurrent documentation

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Documentation

• Design drawings and models: sketches, rough design layout drawings, and initial 3-D computer models created during the ideation and refinement phases

• Production drawings and models: Multiview dimensioned drawings and assembly drawings with a parts list are used for production purposes.

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Figure 16. A design drawing Figure 17. Production drawing

Documentation

• Technical illustrations: used to convey ideas to others on the team early in the design process

• Animations: used to support the marketing, training, production, and service activities

• Technical reports: accounts that chronicle the design process

• Presentation: text, illustrations, and other visual aids used when making an oral report to a group

• Patent drawings: highly regulated piece of graphics.

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Figure 18. Technical illustration

Figure 19. Pictorial patent drawing

Product Data Control

• A critical part of the design process is managing all of the information related to the product.

• Product data management is a computer-based tools and processes used to manage this information

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Figure 20. PDM in a networked environment

Standards and Conventions

• Standards and conventions are the “alphabet” of technical drawings, and plane, solid, and descriptive geometry are the science which underlies the graphics language.

• Conventions commonly are accepted practices, rules, or methods. Example: the use of dashed lines on multiview drawings to designate a feature hidden from the current viewpoint.

Figure 21. Drawing standard

• Standards are sets of rules that govern how technical drawings are represented. Example: placing the dimension text such that it is read from the bottom of the sheet

Figure 20. Drawing conventions

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Other Engineering Design Methods

Design for Manufacturability (DFM): the design technique in which the design is developed by a team and the focus is on simplicity in manufacturing and functionality DFM principles are as follows: – Minimize the number of parts. – Use modular design (breaking a single design into smaller parts). – Use gravity in assembly whenever possible. – Minimize reorientation and adjustment during the assembly process. – Provide easy access. – Reduce or eliminate fasteners. – Increase part symmetry. – Consider ease of part handling. – Design parts for ease of alignment. – Design parts to maintain location.

Knowledge-Based Engineering (KBE): the system that complement CAD by adding the engineering knowledge necessary for a product’s design

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Graphic Communication Technologies

Reverse Engineering: the method of taking an existing product, accurately evaluating it, and putting the information into a CAD database

Web-based Communication: Now it is possible to share design information in a new way. Physical presence is no longer necessary for the people doing the design or the documents used to support the design process

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Figure 22. Coordinate measuring machine

Graphic Communication Technologies

Output Devices: can be used to make check plots, production plots, presentation plots or combining of these

Storage Technologies: storage devise is used to store information

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Figure 25. Stereolithography system Figure 24. Laser jet printer Figure 23. Design jet printer

Virtual Reality

• Virtual reality (VR) is a 3-D (in most cases, but not always), computer-generated, simulated environment, rendered in real time with interactive user control of the environment.

Figure 26. Components of VR

• The use of VR in industry is becoming more common for oil and gas exploration, engineering design — especially in the automotive and aerospace industries — and scientific visualization for research in many of the basic sciences.

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Summary

• Visualization – the ability to mentally control visual information

• Graphics theory – geometry and projection techniques • Standards – sets of rules that govern hoe parts are made

and technical drawings are represented • Conventions – commonly accepted practices and methods

used for technical drawings • Tools – devices used to create engineering drawings and

models, included both handheld and computer tools • Applications – the various used for technical graphics in

engineering design, such a s mechanical, electrical, and architectural

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