The Core Concepts of Technology

1. The Core Concepts of Technology ETP 2006—Tanya 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).

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

3. Systems found in Technology • Mechanical • Fluid • Electrical • Thermal • Chemical

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

5. Open-Looped System Has no feedback and requires human intervention

6. Closed-Loop System Uses feedback

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

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

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

10. There is no perfect design All designs can be improved

11. Ingredients of a successful technology design • Safe use of tools and machines • Consider alternate solutions • Test and evaluate solution • Design a solution to the problem • Integrate information from other academic studies • Build a solution to the problem

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

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

14. Drafting Conventions • Line Weight • Dimensioning

15. Line Weight One can communicate more clearly by using varying line weights for different purposes.

16. Types of Lines • Border Line • Object Line • Hidden Line • Dimension Line • Extension Line • Centerline

17. 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.

18. 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.

19. 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.

20. 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.

21. 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 frills—Helvetica Narrow or Arial are good choices.

22. 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

23. 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.

24. 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.

25. 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.

26. 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

27. 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.

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

29. 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

30. CAD/CADD • Could mean: • Computer Assisted Drafting • Computer Assisted Design • Computer Assisted Design and Drafting

31. How to Communicate the Design Proposal • Each member of the team makes their own sketch of the solution to the problem. • Team (group) discussion of the strengths and weaknesses of each solution. • The team might choose to develop a proposal that incorporates a number of features from each design.

32. 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.

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

34. In our everyday experience, designs are communicated or “sold.”

35. 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.

36. 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.

37. 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.