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CAD/CAM/CAE

By Rohitha Keerthiwansa

INTRODUCTION-CAD/CAM/CAEComputer Aided Design - CAD

CAD- is technology concerned with using computer systems to assist in the creation, modification, analysis and optimization of a design.

Any computer program that embodies computer graphics and an application program facilitating engineering functions in design process can be classified as CAD software.

The most basic role of CAD is to define the geometry of design, a mechanical assembly, an architectural structure, an electronic circuit, a building layout etc.

The greatest benefits CAD systems are that they can save considerable time and reduce errors caused by otherwise having to redefine the geometry of the design from scratch every time it is needed.

INTRODUCTION

Computer Aided Manufacturing - CAM

CAM technology involves computer systems that plan, manage and control the manufacturing operations through computer interface with the plant’s production resources.

One of the most important areas of CAM is numerical control (NC). This is a technique of using programmed instructions to control a machine tool that cuts, mills, grinds, punches or turns raw stock into a finished part.

Another significant CAM function is in the programming of robots. Process planning is also a target of computer automation.

INTRODUCTION-CAD/CAM/CAE

Computer Aided Engineering – CAE

CAE technology uses a computer system to analyze the functions of CAD-created products, allowing designers to simulate and study how the product will behave so that the design can be refined and optimized.

CAE tools are available for a number of different types of analyses. For example, kinematic analysis programs to determine motion paths and linkage velocities in mechanisms. Dynamic analysis programs can be used to determine loads and displacements in complex assemblies such as automobiles.

One of the most popular methods of analysis is using a Finite Element Method (FEM).This approach can be used to determine stress, deformation, heat transfer, magnetic field distribution, fluid flow, and other continuous field problems that are often too tough to solve with any other approach.


At present the CAD/CAM/CAE development focused on efficient and fast integration and automation of various elements of design and manufacturing along with the development of new algorithms. There are numerous CAD/CAM/CAE packages available for direct usages that are user friendly and very proficient. Here are some of the commercial packages in the present market AutoCAD, CADKEY, DELCAM, SolidEdge and SolidWorks are some low end and easy to use CAD softwares. Unigraphics, Pro-Engineer, CATIA and I-DEAS are higher order modeling and designing software that are costlier but more efficient. The other capabilities of these software are manufacturing and analysisAnsys, Abaqua, Nastran, Fluent, and CFX are packages mainly used for analysis of structures and fluids. Different software are used for different purposes.ALIBRE, Cyber-Cut and CollabCAD are software which are focusing on collaborative design. Collaborative design is computer aided designing for multiple users working at the same time


Manufacturing Process Figure 1- A diagram representing the product realization process –

CAD/CAM by Ibrahim Zeid


History of CAD/CAM

In 1960’s Ivan Sutherland (1962) –sketchpad- picture can be displayed

and manipulate on the screen CRT Simple 2D graphics Mechanism design satisfying several geometric constraints Design parameter optimization

In 1970 Computer drafting era Wire-frame modeling Free-form surface modeling (mainframe) Solid modeling (late 1970’s)


In 1980’s (The intensive years of research in CAD/CAM)

Early 1980’s CAD/CAM integration Mechanical feature recognition from CAD database

Mid 1980’s Specialized, feature-based CAD system (mini & macro

companies) Feature-based design and parametric modeling

Late 1980’s Design for manufacturing Design for automate assembly


In 1990’s Concurrent engineering design Integrated design, analysis & optimization Virtual-prototyping ( workstation & high-end PC) Research

Wavelet in CAGD (computer aided geometric design) Surface in partial differential equation from which may be

represented by b-spline and & Beizer Geometric modeling algorithm and generation of 3D entities


User Interface

A collection of commands that the user can use to interact with a particular CAD/CAM system. The user interface consists of two parts : user communication and database communication.

The user communication part includes the dialogue that the user follows to achieve specific goal.

The database part includes the geometrical data input to be retrieved from the database

Discussion point

Compare AutoCAD with CATIA V5 R16 and discuss in particular with the user interface, DBMS, coordinate systems .

OVERVIEW OF CAD/CAM WHAT IS CAD?

CAD if often defined in a variety of ways and includes a large range of activities.

Very broadly it can be said to be the integration of computer science (or software) techniques in engineering design. At one end when we talk of modeling, it encompasses the following:

Use of computers (hardware & software) for designing products Numerical method, optimizations etc. 2D/3D drafting 3D modeling for visualization Modeling curves, surfaces, solids, mechanism, assemblies, etc.

OVERVIEW OF CAD/CAM

The models thus developed are first visualized on display monitors using a variety of techniques including wire frame display, shaded image display, hidden surface removed display and so on.

Once the designer is satisfied, these models are then used for various types of analysis / applications. thus, at the other end it includes a number of analysis activities. These could be:Stress (or deflection) analysis, i.e. numerical methods meant for estimating the behavior of an artifact with respect to these parameters. It includes tools like the Finite Element Method (FEM). Simulation of actual use Optimization Other applications like

CAD/CAM integration Process planning

OVERVIEW OF CAD/CAM

These are activities which normally use models developed using one or more of the techniques mentioned above. These activities are often included in other umbrellas like CAM or CAE.

A term often used is CAx to include this broad set of activities. They all use CAD models and often the kind of application they have to be used in determines the kind of a model to be developed.

In this discussion we will strive to give an overview of modeling techniques followed by some applications, specifically CAM.

Thus there are three aspects to CAD.Modeling Display/ Visualization Applications

OVERVIEW OF CAD/CAM

MODELING

Modeling typically includes a set of activities like Defining objects Defining relation between objects Defining properties of objects Defining the orientations of the objects in

suitable co-ordinate systems Modification of existing definition (editing)

APPLICATIONS

3-D MODELING SOFTWARE IN THE MARKET

SOLID EDGE

Pro-Engineer

I-DEAS

SOLID WORKS

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