CAD - CAM - CAE

Casiano Arroyo, ManuelGarrido, RoxanaParedes, Jorge

Quino Quispe, GustavoSanchez Loayza, Luis GuillermoTabuchi Yagui, Edgardo Toshiro

1. Generalities

CAD

CAM

CAE

1.1 History

1.1 History

1.1 History

1.1 History

1.1 History

1.1 History

Computer aided design is defined as the integrated use of computer systems to assist in the creation, modification, analysis or optimization of a design. It is the technology concerned with the use of digital computers to perform certain functions in design and production. It is the major element of computer aided engineering.

Computer-Aided Design (CAD)

Potencialities

•Increase productivity

•quality improvement

•Varity of possible geometries

•Reduced design time

1.2 CAD

Software Applications

Standard model

NURBs modeling (Non Unifrom Rational B-Splines)

1.3 CAM (Computer Aided Manufacturing)

•Machining•CNC•Advantages

1.4 Computer -Aided Engineering (CAE) Is the use of computer software and hardware in the translation of computer-aided design models into manufacturing instructions for numerical controlled machine tools.

Applications CAM takes this one step further by bridging the gap between the conceptual design and the manufacturing of the finished product.

For the sake of convenience, a single computer ‘controller’ can drive all of the tools in a single cell. G-code instructions can be fed to this controller and then left to run the cell with minimal input from human supervisors.

•stress analysis•vibration analysis•Structural analysis• Noise thermal distortion, etc.•Explicit Dynamics•Fluid Flow•Harmonic Response•Linear Buckling•More applications…

Process of CAEExample: Stress Analysis•Create a part or an assembly.•Define properties.•Material selection•Define analysis steps.•Define interaction.•Loads.•Mesh•Job.•Visualization.

2. CAD

2.1 Theory

CAD – Computer Aided Design

Raster & Vector

2D: Pixel3D: Voxel

2D: Geometry Figures3D: Solid Geometry

2D: Bezier Curve

• Used commonly in 2D Graphic Design softwares.

2D: Spline

• Used in 2D modeling software

2D to 3D

3D: CAD

CAD

CAD

Boundary representation (B-Rep)

Boundary representation models are composed basically of two parts:

Topology: & Geometry

Boundary representation (B-Rep)

• Topology: faces, edges and vertices.• Geometry: surfaces, curves and points.

Extended Euler Poincarré formula:Faces + Vertices – Edges – Rings = 2(Shells   Holes)

Boundary representation (B-Rep)

• The extended Euler Poincarré formula allow test the topology for polyhedral solids:

Faces = 3Vertices = 0Edges = 2

3 + 0 – 2 – 0 … 2 (1 – 0 )

Constructive solid geometry (CSG)

• Primitives: cuboids, cylinders, prisms, pyramids, spheres, cones.

• Operations: union, intersection and difference.

Constructive solid geometry (CSG)

Constructive solid geometry (CSG)

• Infinite cylinder, I: x^2 + y^2 – r^2 <= 0• Infinite planar half space, P: Ax + By + Cz + D <= 0• Cylinder with ends: I ^ P1 ^ P2

Constructive solid geometry (CSG)

Function representation (F-Rep)

Function representation (F-Rep)

• The objects defined by a single continuous real-valued function of point coordinates F(x)

• The points with F(x) >= 0 belong to the object.• The points with F(x) < 0 are outside of the

object. • The point set with F(x)=0 is called an

isosurface.

B-Rep vs F-Rep

• Calculating surface area is easy• The model is evaluated• Easy to triangulate the surface• Making pictures is easy• B rep primitives are local

• Calculating volume and mass is easy• The model is unevaluated• Easy to make numerically robust• Input is pretty straightforward• The data structures are compact

B-Rep vs F-Rep

Ray Tracing

The Z-buffer

All commercial systems are B Rep. because the the depth buffer or Z-buffer is the predominant technology.

The silicon graphics and flight simulator then the computer games impulse that technology.

• For each pixel store both colour and depth• Send it 3D coloured triangles in any order• Surfaces in front win

The CAD softwares – B-Rep

• They grew out of 2D drafting• B Rep is quick to render on ancient computers.

parametric design

parametric geometry

geometrics parametrics

parameter

2.2 Parametric Design

parametric design

parametric geometry

geometrics parametrics

parameter

parametric design

parametric geometry

geometrics parametrics

parameter

reality

irreality

+ Matter & Energy

- Information

- Matter & Energy

+ Information

R R

A ∏

R =

A

B

n…

1

2

A = …B = …1 = [A+B+….]2 = [1+B+A…]

emotion

passion

creative freedom

responsibility

impact

possibility

M E I

new tools new concepts

new tools new concepts

F. Dysonthe evolution of science

use

2. CAD2.3 Software

2D: Softwares: Inkscape

2D: Softwares: Illustrator

2D Softwares: Corel Draw

2D: Softwares: Photoshop

2D: Softwares: Cabri Geometry

3D Software: Blender

Modeling, animation, created by NeoGeo

3D Software: Rhinoceros

industrial design, architecture, marine design, automotive design, CAD / CAM, rapid prototyping, reverse engineering, industry as well as graphic design and multimedia

3D Software: SolidWorks

3D Software: Catia

3D Software: Pro Engineer

3D Software: AutoCAD

3D Software: Maya

3D Software: Inventor

3D Software: Solid Edge

3D Software: Generative components

Parametric CAD software developed by Bentley Systems

3D Software: Visual Nastran 4D

3D Software: World Craft

3D Software: Revit

3D Software: Tekla

2. CAD2.4 Examples

2.41 Computarization

It focuses only in the use of the software.It requires knowledge knowledge about the software and its tools.Example•Model a cylinder

Method 1

• Create new document.• Create the sketch.• Assign dimensions.• Create the operation Extrusion.

2.42 Computation

It focuses more in logic than in the use of the software.It requires knowledge of algorithms.Example•Model a cylinderHere a program was created using Visual Basic and the API of Solidworks.

Method 2

2.43 Another Example

Example: Model a gearMethod 1• Draw the geometry of gear’s tooth.

• The geometry of the gear’s teeth is complicated to draw.

• Each new gear would be a new problem to solve.

• Thus it is strongly recommended to create a routine to create gears with some initial parameters.

• Creating a program or script.

Method 2

Project

Choose an object of the nature. Analize it and create a software or

script to generate its geometry.