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LECTURE THREE

Geometry Creationand CAD

Drawing Assignment #1

an exploded view of the assembly with aparts list

isometric view of each object with clearexposition of important features

three views of each object using thirdangle projection

the three views will include all relevantdimensions and tolerances as appropriate

material specifications

Assignment Submission

The School has a central assignmentsubmission system with barcode scanning

Students MUST submit a customisedcoversheet for all assessment items

You can create an assignment coversheet

by going MECH2305 Course profile Drawing Assignment #1

under assignment submission you will find a linksaying Click here to create a coversheet

Title Page

The Title Pageneeds to be signed

Submissionswithout a signeddeclaration, will bemarked off by 10%

Assignment #1 Due Date

Due Date = Thursday, 6 April 2006

Late Submissions will PENALISED asper Course Profile

Exploded View

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ThreeViews

Part Tutorials

Basic modelling a front loader bucket

Intermediate

modelling a yoke

Advanced

helical feature

Assembly Tutorials

Basic

creating a slider assembly

Intermediate

creating a grinder assembly

Advanced modeling a cover associatively

Draft Tutorials

Basic

detailing drawing (Use the appropriateA2 size prototype drawing templaterather than the Solid Edge default)

Intermediate

exploded assembly view

Why 3D CAD?

The output is drawn on paper

A paper sheet is two-dimensional

Why dont we start and finish in 2D?

NOTE: Historically, it took two decadesfor the engineering design industry inAustralia to switch from 2D to 3Ddrawing.

Advantages of 3D CAD Easy to visualise the design object

Automation in generating 2D drawings

Geometric properties Weight

Centre of mass

Interference checking

Improved quality

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More advantages of 3D CAD

Easy to receive feedback from clients Parametric designs

Standardisation

Engineering Design Change Tracking

Integrated Product Development Design

Drawing

Analysis

Manufacturing

A Model

Model The 3-D computer graphicsobject that the user creates Part Model

Assembly Model

Surface Model

Finite Element Model

Part Model

Part Model A single component thatcan be stored as a separate object Part 1 The small hinge plate

Part 2 The large hinge plate

Part 3 The pin

Feature

Feature A self-contained segmentof a part model Protrusion (eg a boss)

Cut-out (eg a slot)

Hole (eg threaded, counterbore, etc)

Assembly Model

Assembly Model Collection of PartModels An assembly model may contain many

parts

Each part will be a separate model

An assembly model is merely an index ofthese models and theirinterrelationships

An Assembly Model

1

2

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A Part Drawing Wireframe View

Wireframeview Showsonly theedges.Surfaces arenot rendered.

Solid View

Surfaces areshown asopaque. Theinterior ishidden.

Surfaces maybe shaded andrendered.

Modelling a Part

Select the sketch plane

Create the 2-d geometry

Make the 3-d feature Extrusion (Solid Edge calls it Protrusion)

Revolving Sweeping

Protrusion

Constructs a protrusionby extruding a profilealong a straight path. Another protrusion

built onto the first one

Revolved Protrusion

Constructs aprotrusion byrevolving aprofile

Build a ring around thecylinder using the samecommand

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Revolved Cut-out

Constructs a cutoutby revolving aprofile

Sweep - Protrusion

Constructs a protrusion by extruding aprofile (A) along a path you define (B).

Sweep - Cutout

Constructs a cutout by extruding aprofile (A) along a path you define (B).

Geometric Relationships

Right AngleParallel EdgesThe lines connect at the corners

Centre LocationRadius

Geometric Constraints Collinear

Connect

Concentric

Equal

Horizontal/Vertical

Tangent

Symmetric

Parallel

Perpendicular