Orthographic Projection Engineering Drawing BDU 10303
Objectives To understand the basic principles of orthographic projection To be able to draw simple objects using orthographic projection
Orthograpic Projection A collection of multiple two-dimensional drawings that work together to get an accurate representation of an object.
Orthographic projection
Orthographic projection
Conventional orthographic view All views must be properly aligned!
Guidelines Pick front view that is most descriptive of object. Position the object in its natural position. Choose the view that shows minimum hidden lines. Longest dimension is normally chosen as width. Usually only three views are used: Front, top and side views
First and Third Angle Projection Orthogonal plane First angle projection Third angle projection ortho = perpendicular
Orthogonal plane
First angle projection Symbol:
First angle projection
First angle projection
First angle projection
First angle projection
First angle projection
Third angle projection Symbol:
Line types what is phantom lines? Phantom lines are used most frequently toindicate an alternate position of a moving part.
Drawing Layout All engineering drawings should feature a title block that include: Title Name Checked Version Date Notes Scale Company name Projection
Exercise 4 Draw an orthogonal projection of the following object using the third-angle projection
Dimensioning
Dimensioning shows two common methods of dimensioning a circle. One method dimensions the circle between two lines projected from two diametrically opposite points. The second method dimensions the circle internally is used when the circle is too small for the dimension to be easily read if it was placed inside the circle.
Section views Shortcoming: Orthographic view may shows all hidden lines but may not clear enough to describe an object’s INTERNAL details. To overcome this, imagine the part of the object has been cut and shown in cross-section view.
Type of section views Full section view Offset section view (Multiple offset views) Half section view Broken section view Aligned and revolved section view Removed view
Full section view
Offset section view
Multiple offset sections
Half section view
Broken section view
Example 1 2xΦ8
Example 2
Exercise 5 orthographic projection of the following object with full section view R4.0 5.0 A 8.0 A 2.0 2.0
Quiz 3 2. Draw the orthographic projection of the following object with full section view Φ1.54 Φ1.08