AutoCAD Tutorial: Part 2

1
AutoCAD Tutorial Part 2

• Learning Objectives
• To refresh your memories in operating AutoCAD
• To practice on constructing solid model
• www.siit.tu.ac.th/karndee/course/autocad.html

2
3D Modeling Basics

• Wireframe models
• Surface models
• Solid models

3
Wireframe Model

• Represents edge of actual object
• Surfaces of object are not defined
• Transparency and no volume
• 2D objects in 3D space
• Use Line, Circle, Arc

4
Surface Model

• Edges and surfaces are defined
• Object has volume but no mass
• Each surface is constructed individually
• Each surface is created / move to the correct
  orientation w.r.t other surfaces
• Easier to visualize than wireframe
• Can be displayed in wireframe or hidden view
• ? Draw / Surfaces
• Command _hide

5
Solid Model

• A complete computerized replica of the actual
  object
• Complete surfaces, edges, interior features of
  the object
• Object has volume and mass
• Can be displayed in wireframe or hidden view
• Constructing primitive shapes
• Using Boolean operations to create composite
  solid

6
Constructive Solid Geometry (CSG) Techniques

• Primitive Solids
• ? Draw / Solids
• Box
• Cone
• Cylinder
• Extrude
• Revolve
• Sphere
• Torus
• Wedge

• Boolean Operations
• ? Modify / Solid Editing
• Union
• Joins selected solids
• Subtract
• Subtract one set of solids from another
• Intersect
• Create a solid of intersection (common volume)
  from the selected solids

7
Part Sample(to be used in CAM section)
SW Isometric View
8
Part Sample(to be used in CAM section)
Top View
9
Common Operations

• Drawing Environments
• Metric unit orientation
• Set the drawing limit
• Set isometric viewpoint
• Primitive Solids and 2D Object
• Solid boxes
• Cylinders
• Rectangular

• Object Modification
• Fillet
• Extrude
• Subtract
• Union
• Move
• Dimensioning

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Step 0 Setup the environment

• Set the environment at start up
• Metric setting
• Viewing in 3D
• View / 3D Views / SW Isometric
• Select common operations from Toolbar
• View / Toolbars
• Select Solid Editing, View Point, Object Snap,
  Modify,

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Step 1 Solid box

• Create solid box at 0,0,0
• Define size of the box 50,50,15
• x, y, z coordinate

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Step 2 Solid from 2D object

• Create separate object (2D rectangular with the
  size 44, 44
• Round one corner Fillet (radius of 22)
• Create a solid object using Extrude feature
• Draw / Solid / Extrude
• Height 5 Taper 0)

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Step 3 Solid cylinders

• Create separate solid objects 2 Cylinders
• Diameter1 20 Diameter2 10 Height 5
• Use Subtract command to create a hole (Modify /
  Solid editing)

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Step 4 Move Objects

• Move rounded square object to the base part
• Use object snap to help locate the positions
• Subtract small box from the bigger box

15
Step 5 Move objects

• Move a cylinder object to an appropriate position
• Move at the base of the cylinder to 22,22,10
• Combine (Union) 2 objects

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Step 6 Round Corners

• Round the edges using Fillet (radius of 2)

17
CAD Assignment

• Guidelines and Minimum Requirements
• Section 1 Part Design
• Each student has to select and design an
  applicable part that satisfies the following
  conditions
• -         The part must serve a least one
  practical purpose.
• -         The part must be a single solid object
• -         The overall dimension must not exceed
  W20cm xL20cm x H20cm
• -         The part should have at least one curve
  surface
• -         The part should have at least one hole
  (e.g., cylinder hole, rectangular hole, cone)
• -         At least one corner of the part must be
  rounded with indicated dimensions.
• -         The part should have one island
• - All dimensions have to be indicated in either
  isometric view or in several 2 dimensional views.

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CAD Assignment

• The part should be able to be machined by at
  least two of the following operations (but not
  limit to)
• Milling, Turning, Wire cutting EDM, Die sinking,
  Threading, Drilling, Boring, Bending
• Cleary indicate the type of material for your
  designed part.
• Clearly indicate your name and last name in the
  drawing. It can be written directly on the
  designed part or within the drawing area.

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CAD Assignment

• Section 2 Written Report
• Each student has to submit one written report
  that thoroughly explains the design steps of the
  part. Step-by-step instructions accompanied with
  figures are required. The report must also
  explain the machining operations of the designed
  parts.
• Ground Rules and Policies
• Students are required to submit CAD assignment
  package which include a CAD file in floppy disk
  (one diskette for one file) and a written report.
  Clearly label your name and student ID on the
  submitted floppy disk and report.
• The CAD assignment package dues at
• 4 p.m. on December 28, 05 (Wednesday).
• 4 p.m. on February 8, 2006 (Wednesday)
• No late assignment is accepted.
• This assignment must be an individual work. Do
  not copy your friends. Any assignment in
  question will receive a zero score for CAD
  section. And no rework of any kind is accepted.