The Core Concepts of Technology

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The Core Concepts of Technology
ETP 2006Tanya Mattson This material is based
upon work supported by the National Science
Foundation under Grant No. 0402616. Any opinions,
findings, and conclusions or recommendations
expressed in this material are those of the
author(s) and do not necessarily reflect the view
of the National Science Foundation (NSF).
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Systems

• A group of interrelated components designed
  collectively to achieve a desired goal.
• Parts of a system
• Input
• Process
• Output
• Feedback

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Systems found in Technology

1. Mechanical
2. Fluid
3. Electrical
4. Thermal
5. Chemical

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• Systems often work together to make the
  technology work.
• Systems are made up of related subsystems.
• Technological systems often interact with each
  other.

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Open-Looped System

• Has no feedback and requires human intervention

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Closed-Loop System

• Uses feedback

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Resources

• Things needed to get the job done.
• Basic technological resources
• Tools and machines
• Materials
• Information
• Energy
• Capital
• Time
• People

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• Most systems and products have requirements
  placed on them. These are the parameters often
  referred to as CRITERIA and CONSTRAINTS

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• Designing is the process of applying creative
  skills in the development of an invention or
  innovation.

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• There is no perfect design
• All designs can be improved

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Ingredients of a successful technology design

1. Safe use of tools and machines
2. Consider alternate solutions
3. Test and evaluate solution
4. Design a solution to the problem
5. Integrate information from other academic studies
6. Build a solution to the problem

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1. Receive formative and summative feedback from the
   teacher
2. Make sketches and drawings of potential solutions
3. Utilize a design or problem solving model
4. Assess the impacts and consequences of technology

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Controls

• The mechanisms or activities that use information
  to cause a system to change.

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Drafting Conventions

• Line Weight
• Dimensioning

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Line Weight

• One can communicate more clearly by using varying
  line weights for different purposes.

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Types of Lines

• Border Line
• Object Line
• Hidden Line
• Dimension Line
• Extension Line
• Centerline

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Dimensioning

• A few guidelines
• All lettering should be positioned so as to be
  read from the bottom of the drawing.
• Most dimensions and notes should be presented
  next to the front view, and not be repeated on
  top or side views.
• Information should be placed between the views,
  not on the object itself or outside of the views.

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• Place largest or longest dimensions farthest from
  the object.
• If part is to be machined by a computer (CNC),
  all dimensions should reference x 0 and y 0
  (lower left corner of the drawing).
• Curved surfaces are described by radius.
• Circles or holes are described by diameter.

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• Extension lines should not touch the object, but
  extend beyond the dimension line. Centerlines do
  touch and extend beyond the object.
• Hand drawn dimension lines have arrowheads that
  are about 3 times as long as wide.

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• Hidden lines, represented by evenly spaced dots
  and dashes, do touch each other if they
  intersect, and also touch a visible line if they
  intersect.
• Hidden lines and centerlines do not touch if they
  intersect.

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• Construction lines are drawn very thin and light,
  with the intention of being erased after serving
  as an alignment aid.
• Guidelines are thin and light, drawn as an aid in
  creating uniform hand lettering.
• If using a CAD system, one should choose a simple
  font that is highly legible with no
  frillsHelvetica Narrow or Arial are good choices.

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Orthographic Projection

• By tradition, the front, top, and side views are
  shown.
• These 3 views are connected by imaginary lines so
  that one can see a correspondence between the
  views.
• Some features are hidden or fore-shortened

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View Selection

• How do you choose the front view?
• The front of a complex object can often be
  answered by choosing the side that reveals the
  most information.
• If necessary, a special view is created. These
  are called an AUXILIARY VIEWS.

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Oblique Projection

• This method is sometimes used in both sketching
  and drawing.
• This is the simplest method of pictorial
  representation.
• Typically, you begin with a full, straight on
  front view, and depth is represented as
  fore-shortened, and at a 45 degree angle.

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Isometric

• There is no front view, as all views are
  foreshortened.
• The viewer looks at a corner of the object, and
  only the height is shown to scale.

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Perspective

• The most accurate method of projection.
• The object gets smaller the farther away it is.
• The artist/draftsperson chooses 1, 2, or 3
  vanishing points off in the distance on the
  horizon.
• 1 point easiest

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Sketching

• Sketching is probably the only approach to design
  expression that will permit one to focus on the
  design problem
• Either by hand or electronically
• Good design practice demands that a number of
  options be considered.

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Sketching

• Only a grid sheet and pencil are allowed.
• This is how great ideas first take shape.

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Isometric Sketching

• Most difficult to draw
• Three (3) basic types of elements that one needs
  to be familiar with
• Rectangular
• Cylindrical
• Sloped or angled surfaces

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CAD/CADD

• Could mean
• Computer Assisted Drafting
• Computer Assisted Design
• Computer Assisted Design and Drafting

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How to Communicate the Design Proposal

1. Each member of the team makes their own sketch of
   the solution to the problem.
2. Team (group) discussion of the strengths and
   weaknesses of each solution.
3. The team might choose to develop a proposal that
   incorporates a number of features from each
   design.

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• A new sketch is made as a result of the group
  decision.
• A prototype is built.
• The design would most likely be modified AT LEAST
  once more before presenting it.

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• The design process also includes being able to
  effectively present your solution.

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• In our everyday experience, designs are
  communicated or sold.

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How are they sold?

• Presentation of the product
• Power Point
• A display
• Prototype of the product
• More realistic drawings that provide much more
  information than the 1st crude sketches.
• Etc.

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Standards and Benchmarks

• 8 Students will develop an understanding of the
  attributes of design.
• 8.E Design is a creative planning process that
  leads to useful products and systems.
• 9 Students will develop an understanding of
  engineering design.
• 9.F Design involves a set of steps, which can
  be performed in different sequences and repeated
  as needed.

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Internet Search Worksheet Questions

• Explain the 6 types of lines used in dimensioning
  and draw an example of each
• Border Line
• Object Line
• Hidden Line
• Dimension Line
• Extension Line
• Centerline
• Explain what an Isometric drawing is.
• Explain what an Oblique drawing is.
• Explain what an Orthographic Projection is.
• Explain what Perspective Projection is.
• What are the 2 drafting conventions?
• What is Computer Assisted Design?
• List 3 ways you can sell a design proposal.