What is Engineering Graphics

Transcription

1 What is Engineering Graphics is a visual means to develop ideas and convey designs in a technical format. is the dominant means to communication among engineers in industry. Engineering graphics and the skills associated are developed early in an engineer s education.

2 What is Engineering Graphics Several of the topics that are covered in engineering graphics are listed below: Sketching Geometric Modeling Engineering Drawing/Documentation Assembly Drawing Visualization Rapid Prototyping

3 Computers in The Engineering Office Computers are classified as analog or digital. Analog computers are generally used for mathematical problem solving. (control electronic, mechanical equipment) Digital computers count by digits in distinct steps. (electric wall clock) Polish analogue computer ELWAT

4 Historical Background of Computing (1830s) C. Babbage developed the idea of a mechanical digital computer. (undertake laborious calculations ; store the results for further use) (1904) A. Fleming invented the first diode.(allow current to flow in one direction) L. De Forest devised the triode valve. (control the flow of current) Babbage's Difference Engine

5 Historical Background of Computing (1940s) Thermionic valves was used in the first electronic computers.(filling large rooms; generating large amounts of heat) (1947) The first transistor was developed at Bell Lab. (valve computer!) 2nd generation computer; the transistor was introduced. 3rd generation computer; based on small-scale integrated circuits.(early 1960s) 4th generation computer; based on integrated circuit.

6 What is CADD? Computer-aided drawing is a technique where engineering drawings are produced with the assistance of a computer and, as with manual drawing, is only the graphical means of representing a design. Computer-aided design, however, is a technique where the attributes of the computer and those of the designer are blended together into a problem-solving team.

7 Two-dimensional (2D) computer drawing is the representation of an object in the single-view format which shows two of the three object dimensions or the mutiview format where each view reveals two dimensions.

8 Three-dimensional (3D) computer drawing is the coordinate format. Three dimensional computer aided drawing allows the production of geometric models of a component or product for spatial and visual analysis.

9 The advantages of using CADD systems are listed as follow: constant quality drawing creation of database creation of library use of layers saving on repetition greater accuracy multicolour drawings editing functions

10 History And Background 1963 Sketchpad in MIT The first computer aided drawing system was introduced by IBM.

11 Sketchpad was a revolutionary computer program written by Ivan Sutherland in 1963 in the course of his PhD thesis. It helped change the way people interact with computers. Sketchpad is considered to be the ancestor of modern computer-aided drafting (CAD) programs as well as a major breakthrough in the development of computer graphics in general.

12 Ivan Sutherland demonstrated with it that computer graphics could be utilized for both artistic and technical purposes in addition to showing a novel method of human-computer interaction. Sketchpad was the first program ever to utilize a complete graphical user interface. Sketchpad used an x-y point plotter display as well as the then recently invented light pen.

13 The clever way the program organized its geometric data pioneered the use of "objects" and "instances" in computing and pointed forward to object oriented programming. Sketchpad ran on the Lincoln TX-2 computer at MIT. In 1963 most computers ran jobs in batch job mode only, using punch cards or magnetic tape reels submitted by professional programmers or engineering students.

14 History And Background 2 In modern systems the light pen has been replaced by more effective pointing hardware, that is a digitizer tablet, a mouse.

15 CAD system and Hardware (a) the mainframe computer (b) the minicomputer (c) the microcomputer Input Devices The input devices are used for making selections from a menu, which is a layout of a variety of commands and functions required to operate the system. Sending these commands into the computer produces complete engineering drawings.

16 Mouse Light pen Scanner Digitizer (tablet) Joystick

17 CAD system and Hardware 2 Output Devices The output devices receive data from the computer and provide an output, hard copy. (a) impact printers (dot matrix) (b) non-impact printers include electrostatic, ink-jet and laser (c) flatbed plotters (d) drum plotters

18 The User Interface CAD systems may be considered as comprising a large number of functions for creating or manipulating the design model. Traditionally, there are two ways in which this is achieved: Command-based systems Command-based systems operate by reading a command and its parameters entered by the user, carrying out the required actions, then waiting for the next command. command (optional parameters, target object)

19 The User Interface 2 Menu-driven systems The menu-driven approach contrasts markedly with the command approach. The basic principle is that the user is at any time presented with a list or menu of the functions that are available to be selected. The most important of these rules are: A clear, well presented screen layout. Easy function selection by a well-structured menu system. Meaningful function names. Meaningful and helpful prompts to the user. Easily accessible and clearly written help information.

20 CADD FUNCTIONALITY The main benefits of a computerized draughting and design system over those of manual methods is this ability to represent the design of a component or assembly in a geometrically accurate format so that the same model can be used for other modelling, analysis and manufacturing work. The functions can be said to fall into three categories: Synthesis type functions are concerned mainly with the creation of geometric features and drawing details Modification functions include those which allow for the deletion and editing of existing geometry or detail. Management functions are concerned with how the drawing is presented both on the screen and eventually on paper.

21 CADD SYSTEM SELECTION There is a large variety of different CADD packages available on the market these days and the design manager is faced with the enormous problem of selecting a package to suit the demands of the company and its product range. A lot of ease and efficiency has been obtained with the use of CADD systems. Among the more widely used CAD systems are AutoCAD, CATIA, SolidWorks, I-DEAS, and ProEngineer. Most of these packages have both a 2D and 3D component or have an integrated 2D and 3D modeling system. The newer versions of drawing software operate under a menu system which can be accessed through keyboard input or mouse manipulation.

22 CADD SYSTEM SELECTION 2 According to these factors, the system must have; Functional abilities: the abilities to perform memory circuits. Memory capacity : evaluation between main and branch memory circuits. Data transfer characteristics : when we consider data transfer between two computers, or a main computer and a station, we have to keep in mind the need to decrease computing time

23 CADD SYSTEM SELECTION 3 The size of the company and the amount of investment capital available will be one of the main deciding factors but there are many other questions to be considered: Mainframe or PC/workstation platform? Two dimensions or three? Lines, surfaces or solids? Other analysis tools needed? Will the ability to transfer the geometry to these modelling and analysis systems be needed? Compatibility with other systems needed? How good is the maintenance and support from the suppliers? How much, how good and how long is the training? How easy is it to expand the system?

24 AutoCAD AutoCAD is PC-based CAD software products (late 1982). System Requirements for AutoCAD Windows NT or Windows 95/98/2000 Intel 486 or Pentium processor or compatible 32 MB of RAM 50 MB of hard disk space 64MB of disk swap space 2.5 MB of free disk space during installation only CD-ROM drive 640 x 480 VGA video display (1024 x 768 recommended) Windows-supported display adapter Mouse or other pointing device

25 menu bar Docked toolbars 1. Introduction to Computer Aided Drawing Floating toolbar graphic window crosshairs Command line Status bar

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27 MECHANICAL DESKTOP Mechanical Desktop offers greater ease of use, flexibility and speed, 2D drawing capabilities for mechanical design, and greatly expanded 3D goemetric coverage. Mechanical Desktop is an integrated package of advanced 3D modeling tools, and 3D drafting and drawing capabilities that help you conceptualize, design, and document your mechanical product.

28 menu bar Docked toolbars 1. Introduction to Computer Aided Drawing Floating toolbar Desktop browser crosshairs graphic window Command line Status bar

29 Part / Assembly Environment Assembly Mode Scene Mode Drawing Mode

30 PRO/ENGINEER Pro/ENGINEER or Pro/E, is a three-dimensional (3D), featurebased, solids model-ing system. It was developed by Parametric Technologies Corporation (PTC) in the late 1980s. Features are three-dimensional (3D) geometries that have direct analogies to shapes that can be machined or manufactured, such as holes or rounds. Feature-based solids modeling creates and modifies geometric shapes that make up an object in a way that readily represents common manufacturing processes.

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33 SOLID WORKS SolidWorks is mechanical design automation software that takes advantage of the familiar Microsoft WindowsTM graphical user interface. This easy-tolearn tool makes it possible for mechanical designers to quickly sketch out ideas, experiment with features and dimensions, and produce models and detailed drawings.

34 menu bar toolbars drawing document Status bar

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36 I-DEAS (INTEGRATED DESIGN ENGINEERING ANALYSIS SOFTWARE) I-DEAS (Integrated Design Engineering Analysis Software) is a computer aided design (CAD), manufacturing (CAM), and engineering (CAE) package. I-DEAS is a complete Mechanical Computer Aided Engineering System for the engineering department. It provides full function design, analysis, drafting, testing, and NC programming in support of mechanical design automation. This software was designed to facilitate a collaborative concurrent engineering approach to mechanical engineering product design and analysis.

37 I-DEAS The package is separated into five distinct families, which are selected from the first menu option entering I-DEAS. I-DEAS Solid Modelling (Geomod) I-DEAS Drafting (Geodraw) I-DEAS Engineering Analysis (Supertab) contains finite element modelling for finite element solvers such as ANSYS or ABAQUES. I-DEAS System Dynamic (Systan) is used to design complex mechanical system. I-DEAS Test Data Analysis (TDAS) offers tools for general and specific data analysis, project management, and data acquisition

38 I-DEAS Design Application Modeler Task Drafting Simulation Manufacturing Test

39 menu task task specific icons list region graphic region prompt region application specific icons common icons

40 CATIA stands for Computer Aided Three-dimensional Interactive Application, is the most powerful and widely used CAD (computer aided design) software of its kind in the world. CATIA was created by Dassault Systems of France and is marketed worldwide by IBM. CATIA is used by the automotive and aerospace industries for automobile and aircraft product and tooling design.

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43 Web Pages for CAD softwares Autodesk home page Pro-Engineer CAD Software I-DEAS CAD software home page SolidWorks CAD software home page CATIA CAD software home page CADKEY software

44 You will learn parametric design and basic drawing functions. The steps to follow are: Screen Coordinates Geometric Parameters Geometry Creation (Line, Circle, Arc etc.) Modification (move, copy etc) Automatic Functions (dimensioning, cross-hatching etc.) Management (zoom, layering etc.) Prepare a pen & a notebook...