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EngineerDrawings/GDT
ISAT 211
Question | Answer |
---|---|
What characteristics must drawings have? | They must be clear, complete, and accurate |
Layout Drawing | A pure geometric representation of an entire assembly prepared in initial design stages to resolve spatial issues and tradeoffs without full attention to dimensioning or presentation |
Detail Drawing | Supplies complete details for making a single part including its shape and size descriptions, material call-out and specifications of tolerance and surface finish |
Assembly Drawing | Depicts assemblies of fully detailed component parts, arranged as they appear in the final assembly |
What does the title block include? | The part number, its revision and title or description, the name of the company, scale if any, and default values for tolerance and surface finish |
What lines define basic geometric form? | Visible lines, hidden lines, center lines |
What lines associate with dimensions | Extension lines, dimension lines |
What lines are pointing and advisory | Leader lines, break lines, cutting plane and section lines, |
What is the process of creating drawings? | Create drawings with geometric models in a CAD database. Extract 2D views of the part and place it in a blank drawing. The views are dimensioned, toleranced, and customized, and identify descriptive information |
What does pictoral projection mean? | It's isometric, oblique and perspective useful for general illustrations |
What is an orthographic Projection? | Images of an object that are projected onto planes as they appear to the eye when viewed from three orthogonal (mutually perpendicular) directions. |
What are the basic rules for placing linear dimensions? | Place dimensions between views when possible. Place smallest nearest the view being dimensioned. Dimension the view that best shows shape |
Concentric cylindrical features | Best shown in a side view |
One-View drawings | Use symbol θ (metric) or the abbreviation DIA(inch) |
Circular arc | Dimensioned via its radius |
Cylindrical holes | Dimensioned with a leader pointing to the hole and the diameter is preceded by θ or followed with DIA |
Circular Tapers | Find: the diameter of one end of the taper, length of the taper, inclination rate, and taper ratio |
Flat tapers | Dimensioned in a fashion similar to circular tapers |
Chamfers | Dimensioned via their length and angle |
Undercuts | Dimensioned with a note specifying width followed by the diameter |
Coordinate Dimensioning System | Define distance, location and size by means of linear dimensions measured from reference axes or datum planes |
True Position Dimensioning | Features defined in terms of their most likely or mean position |
Polar Coordinate Dimensioning | Define position by means of a radius and an angle |
Chain and Datum dimensioning | dimensioning of features sequentially in a chain-like manner or from a common reference (datum) point or a line. |
Geometric Tolerance | The maximum permissible variation in form, orientation or location of a feature from specifications on the drawing |
4 Vital requirements that GDT meets with a quality drawing | Complete, Functional, Maximum Tolerance, and clear |
Where is third angle projection used | The US, Canada, Japan |
Where is first angle projection used? | Mainly in Europe and some Pacific Rim countries |
What is a cutting plane | Its represented by its edge which is shown in a view perpendicular to the cutting plane itself. |
What is Rounout | The deviation in position of a surface of revolution about a give (datum) axis |
Straightness | A geometric characteristic of lines and line elements of surfaces |
Flatness | A condition in which all surface elements lie on the same plane |