Week 3 Flashcards
Why is projections important?
Knowing projects will improve your sketching ability
you need to know these terms and stuff as an engineer
Knowing these greatly improves your ability for projection
What is isometric projection?
A neither perpendicular or parallel view from one corner
- vertical lines on the object are vertical on the page
- horizontal axes on the object rise at 30 degrees on the page
- Equal distances along the aces on the object are equal on the page
Parallel lines on the object are parallel in an isometric projection! PERSPECTIVE IS NOT TAKEN INTO ACCOUNT (like how 2 sides of a path get closer the further away it is from u)
What is orthographic projection?
When you view an object straight on. You cannot see any other sides of the object other than the one you are facing.
- use front view, top view, and one side view
How do you sketch isometic projections?
lightly sketch an enclosing box
draw the shape inside the box
erase the enclosing box
What are hidden lines?
They are dotted lines that are used to show features inside or on the back of the part (holes, notches behind parts, etc.)
How are circular features usually identified?
They are identified through center marks/lines
These are lines consisting of long-short-long dashes.
You use these to mark the front end of a circle, tubes going through an object, etc.
What is third angle projection?
The arrangement of three orthographic projections with the front view centered, the top view aligned above it, and the side view aligned to the right is THIRD ANGLE PROJECTION
THis is the standard in NA
What is the symbol used to represent third angle proejction?
imagine a 3D truncated cone in third angle projection with the side view on the left.
What elements can be found in a title block?
- third angle projection symbol
- drawing name
- number for drawing
- revision number / letter
- drawing scale
- who prepared / checked it
- details on the units and precision on dimensions
What do dimesons show?
They show the size and location of features
What are the parts of a dimension?
dimension: the number
dimension line: line with the number above it
extension lines: lines that come close to the part, but do not touch it
Where to put dimensions?
do not put dimensions inside the object and try to put dimensions between views ( easy to see how dimensions relate between views)
extension lines are allowed to cross
the arrows on the dimension line can be inside or outside the extension line, but choose the one that lets the dimension be most visible
DO NOT USE REDUNCANT DIMENSIONS
DIMENSION VISIBLE FEATURES INSTEAD OF HHIDEN FEATURES when possible
What should you dimension?
All measurements of a part,
the radius of a circle (with the radius symbol that looks like theta)
angles of non-90-degree parts
