GCSE in Engineering

1
GCSE in Engineering

• Introduction to Design

2
Introduction

• The first part of any engineering activity is the
  design stage. It doesnt matter if its a pair of
  trainers, an oil rig or a DVD player all need to
  be accurately designed and developed.
• In the past, designing would be carried out on
  drawing boards by highly skilled designers and
  drawing office personnel. The introduction of
  computer programs is now very widespread with the
  vast majority of final design work being carried
  out on specialist software.

3
Introduction

• This specialist software is often termed computer
  aided design or CAD for short.
• CAD is used all over to design the plans for
  large structures e.g. housing estates, making
  component drawings and 3D models of products such
  as mobile phones.

4
Introduction

• Even films such as Shrek and Lord of the Rings
  use an advanced type of CAD to construct their
  visual effects.

5
Introduction

• CAD is a software package that can produce high
  quality drawings and models to exact
  specification.
• It enables the operator to draw very quickly,
  effectively and accurately.
• It can open, display and print drawings produced
  by others that can be sent on disk or e-mail.
• Its a software package that will save any
  engineering company time and money.

6
What are the advantages of CAD?

• It produces drawings to a high standard and
  accuracy that is repeatable time and time again
• It can produce drawings more quickly than
  compared to manual methods.
• It can carry out a range of drawing functions
  including 2D and 3D.
• It is user-friendly which requires less manual
  skill to carry out quality drawings

7
What are the disadvantages?

• People may require special training to be able to
  use CAD - this can be expensive
• It can be expensive to buy.
• Less people are required to carry out drawing
  work because it is so much quicker than manual
  methods - this will reduce the amount of
  draughtsman required.
• Some CAD/CAM packages are not compatible with
  others this may hinder development of products if
  different companies use different systems.
  Although AutoCAD is industry standard.

8
How does CAD work?

• Its like having a piece of paper which you can
  set to any size and display on your screen you
  then use a series of commands to construct your
  drawing.
• The commands could be drawing a line, a circle,
  3D shapes, copy, move.etc
• As CAD is very accurate, many of the commands
  need to be co-ordinate based

9
What do I need to get started with CAD?
Processor Hardware i.e. Computer drive /
processor etc Software i.e. AutoCAD Lt or R14
Outputs VDU Printer Plotter Completed file
Inputs Keyboard Mouse Scanner Tablet
10
Any Questions?
11
Co-Ordinates
y
(12,15)
15
x
12
12
Absolute Co-Ordinates

• 100,100 (ENT) 170,100 (ENT)170,155 (ENT)
• 100,155 (ENT) 100,100 (ENT) (ENT)
• 100,155 (ENT) 135,180 (ENT) 170,155 (ENT)

13
Relative Co-Ordinates

• 100,100
• _at_70,0 _at_0,55 _at_-70,0
• _at_0,-55 _at_35,25 _at_35,-25

14
Polar Co-Ordinates

• 100,100 _at_100
• _at_100
• 100,100 _at_50
• 110,60 _at_15
• 112,62 _at_11

15
AutoCAD Glossary
16
Commands

• Line - Draws a line from any two points, requires
  start point and end point.
• Circle - Draws a circle from any centre point,
  requires a diameter or radius.
• Fillet - draws a radius between two lines to make
  and arc requires radius and two selected lines.
• Chamfer - draws a line at a set indent distance
  between two lines to make an angle, requires a
  distance and two selected lines.
• Offset - Copies an object (e.g. line or circle) a
  specified distance away from the original

17
Commands

• Erase - Deletes a selected object.
• Object Snap - Can be used to find the endpoint,
  midpoint, intersection etc of lines or centre
  point, tangent, quadrant of a circle.
• Hatch - Used to place a set pattern of lines
  within an area such as the strap on the watch.
• Array - Used to copy an object a set number of
  times in either a polar (circular) or rectangular
  (straight) direction.

18
Conclusion

• The Introduction to Design and the use of CAD is
  complete. You should by now understand the
  following
• Why CAD is used.
• The basic operation of CAD.
• The advantages and disadvantages.
• Where CAD could be used in engineering.
• We will return to CAD to create 3D models in the
  future.

19
Conclusion Exercise.

• Produce a short report using Word to include
  the following information.
• What is CAD?
• What has CAD replaced in industry?
• How is it used in the design of products?
• What are the benefits of using CAD?
• Are there any disadvantages?
• Include any drawings, images to support you work
  although clip-art and word-art are not
  necessary.