FORE School of ManagementWMG 19, Group - 1

Computer-Aided Design (CAD) Use of computer systems to assist in the

creation, modification, analysis, and optimization of a design Typical tools: Tolerance analysis Mass property calculations Finite-element modeling and visualization

Defines the geometry of the design

Computer-Aided Manufacturing (CAM) Use of computer systems to plan,

manage, and control manufacturing operations Direct or indirect computer interface

with the plants production resources Numerical control of machine tools Programming of robots

Computer-Aided Engineering (CAE) Use of computer systems to analyze

CAD geometry

Allows designer to simulate and

study how the product will behave, allowing for optimization

Finite-element method (FEM) Divides model into

interconnected elements Solves continuous field problems

Computer-Aided Design Process Two types of activities: synthesis and analysis Synthesis is largely qualitative and hard to capture on

computer Analysis can be greatly enhanced with computers Once analysis is complete, design evaluation- rapid prototyping Software packages for design optimization

Components of CAD/CAM/CAE Systems Major components are hardware and

software allowing shape manipulation Hardware includes graphic devices and their peripherals for input and output operations Software includes packages that manipulate or analyze shapes according to user interaction

Components of CAD/CAM/CAE Systems

Hardware Components Graphic device is composed of a display processing unit, a display

device, and one or more input devices Input devices: Mouse Space ball Data tablet with a puck or stylus Keyboard Output Devices: Plotters Color laser printers

Hardware Configuration

Hardware ConfigurationRequires a big initial investment for hardware and software Slow system response times

Maintenance of mainframe is expensive

Updating operating systems is difficult

Hardware Configuration

Hardware Configuration #2Engineering workstations connected in a networked environment Widely used; trend toward distributed computing

User can choose appropriate workstation on a task by task basis

Initial investment is smaller than configuration #1

Hardware ConfigurationPopular with small companiesSame as the second, except engineering workstations are replaced by personal computers running Microsoft Windows

Popular with companies whose main purpose is to generate drawings with their CAD/CAM/CAE systems

Distinction between configurations 2 and 3 becoming blurred as personal computers evolve

Software Components CAD software allows the designer to create and

manipulate a shape interactively and store it CAM software plans, manages and controls the operations of a manufacturing site CAE software analyzes design geometry, allowing designer to study product behavior

Windows-Based CAD Systems User interface is similar to Windows Employs component technology, in which best key

software elements are selected from among available software Use object-oriented technology, which modularizes the program Capable of either parametric or variational modeling Internet support

Rapid Prototyping Layer by layer fabrication of three-

Rapid Prototyping has surgical applications

dimensional physical models from CAD Fast and inexpensive alternative for producing prototypes and functional models Build parts in thin layers Minimum operation time; typically runs unattended

Medical Modeling - Zcorp

Rapid Prototyping Cycle

Rapid Prototyping Cycle STL is standard file format for all

U.S. rapid prototyping systems Preprocessing prepares .STL file for various rapid prototyping systems Build process can last from a few hours to several days Post processing: removal of part from machine, support removal, sanding

Rapid Prototyping ProcessA computer-controlled laser beam is scanned across the surface of a vat of liquid photopolymer, instantly solidifying the liquid at each point of contact. Using data generated from a CAD file, individual cross-sections of the threedimensional geometry are solidified in turn to build up a solid part layer by layer. In this way even highly complex geometries can be built in a few hours without requiring any tools.

Need for CAD/CAM

To increase productivity of the designer

To improve quality of the designTo improve communications To create a manufacturing database

To create and test toolpaths and optimize themTo help in production scheduling and MRP models To have effective shop floor control

The Design Process : Then and Now

Before CAD

After CAD

CAD/CAM and the new Environment

Will CAD work for me? Speeding up the prototype testing process, and consequently, shortening the product design cycle

significantly? Taking advantage of 3D modeling tools to translate visions into realities? For industrial designers today, "doing whatever it takes" often means using 3D design tools--whether for visualization or engineering analysis--to speed up the product design process. Increasingly, industrial design teams are finding that the ability to design and communicate using 3D models offers a key advantage over traditional methods.

Will CAD work for me? To best describe a product in order to gain approval from marketing?

Provide instructions to manufacturing? To best describe a product in order to gain approval from marketing, conceptual designs are

often presented in 3D. To provide instructions to manufacturing, a 3D model can be rotated and examined for better understanding. During the development phase, the designer and the engineer can work more closely in refining the product definition if they are looking at and sharing information based on a common 3D model.

How Does It Work? Geometric modeling Automated drafting and documentation Engineering analysis and design analysis

How Does It Work? Geometric modeling Uses basic lines, curves, and shapes to generate the

geometry and topology of a part 2D Technical drawing General-Purpose drafting 3D Difficult to master Freely rotate and zoom a model

How Does It Work? Automated drafting and documentation Produces engineering drawings directly from the CAD

database More advanced documentation merges text and graphics to produce assembly drawings, bills of material, instruction manuals and reports, parts catalogs, and sales brochures

How Does It Work? Engineering analysis and design analysis Is also called computer-aided engineering Tests and analyzes designs on the computer screen CAE retrieves the description and geometry of the part from a CAD database and subjects it to testing and analysis on the computer screen without physically building a prototype.

Advantages Reduce the lead time for new product introduction Products can be tested more quickly Costly mistakes in design or production can be

avoided Efficient drafting and modeling tool Animated walkthroughs or fly-bys Interactive virtual tours through buildings that have yet to be built. Reduce time to market

Advantages Time to manufacture can be reduced Documentation can be printed in various forms for

multiple users The quality of designs and the products manufactured from them is improved CAD systems enhance communication and promote innovation in multifunctional design teams by providing a visual , interactive focus for discussion. To facilitate discussion or clarify a design, CAD data can be sent electronically between designers and suppliers or viewed simultaneously on computer screens by different designers in physically separated locations

Disadvantages Incompatibility Complex Surfaces

In the automotive industry, each of the major auto manufacturers uses a different CAD system for its vehicle and component design and engineering

efforts. These systems are not interoperable, which means they cannot read each other's data formats. This lack of compatibility of CAD software costs manufacturers in the automotive industry alone $1 billion a year, according to a 1999 study by the National Institute of Standards and Technology (NIST).

Disadvantages As long as suppliers have difficulty sharing CAD data with

manufacturers, any time a machinist must reproduce the engineer`s design in a different CAD package or whenever contractors must allocate time to cross-train employees in a new client`s favored software, the advantages that CAD provides are rapidly diminished. Suppliers can`t afford to continue wasting time dealing with the mounting incompatibility problems. Overall, US industry would have a big competitive advantage if the CAD software developers would get together and find solutions to these problems. Vendors, users, and experts agree that one of the biggest

problems in modeling complex surfaces is creating surfaces that interface with each other properly. Another major challenge is controlling surface normal tangencies.

Future Trends Design software is getting easier to use National CAD standard The goal of the National CAD Standard (NCS) is to

encourage voluntary adoption of a standard to streamline and simplify the exchange of information with computer-aided design (CAD) software. This consensus-developed standard incorporates CAD publications of multiple organizations. Adoption of the NCS is intended to save time and money on developing standards.