Transcript Week 6 Lecture - Auxiliary Views

TECH 104 – Technical Graphics Communication
Week 5:
Auxiliary Views
TECH 104 – Technical Graphics Communication
Here’s what we talked about
last time…..
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
We place hidden lines
in a drawing to do the
following things:
1. Show hidden features
2. Clarify the position
and shape of features
3. Make the “plate” more
readable
(NOTE: The term
“plate” refers to a
finished drawing.)
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Note how hidden lines
follow specific rules as
to how they are to be
laid out.
Depending on the application, hidden lines will either touch
other hidden lines, or pass over them
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Center lines are used to
show the theoretically
perfect center of holes,
arcs, cylinders and bolt
circles*
*A “bolt circle” is used to
position holes or cylinders
in a circular pattern.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Rounds and Fillets are used to relieve stress and finish edges
on manufactured goods.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
“Revolved” views are used to give a clearer representation of an
object. We actually “draw the object incorrectly to make it easier
to understand”. Here, webs have revolved to 12, 3 and 6 o’clock
positions to make the view easier to visualize.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Here, the correct
view of the object
will appear to be a
mass of hidden lines
in the right side
view.
By representing only
the 12 & 6 o’clock
positions, we create
a view that is easier
to understand.
Further notes would
be added to the
front view during
dimensioning.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Arms and spokes
are often revolved
to create a view of
the object that is
easier for the
human brain to
visualize.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Let’s now take a look at how
we can show an oblique
surface’s “True Shape and
Size” using auxiliary views…..
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
We have already seen
how the principle views
of an object can be
represented when using
the glass box approach
to surface identification.
However, this object has
a surface that is not
parallel to any side of
the glass box.
How can we represent
that surface in its true
shape and size?
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Here, surface ABCD is
shown in all 3 views.
In which view is it true
shape and size?
Answer:
In none of them!
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
We can also use the glass
box technique by adding
another plane and project
this surface unto it.
By doing so, we can show
the slanted surface’s true
shape and size.
NOTE:
The new glass plane is
parallel to the surface it
describes just like the
other glass projection
planes.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Just the way we
unfold the glass
box to expose all
of the principle
views…..
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
…we can unfold the
projection plane that
is parallel to the
slanted surface we
wish to show as true
shape and size.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
We see that the new
auxiliary view will be
projected from the
front view where the
surface appears as
an edge.
Here’s why we do
this…….
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Between each view are
imaginary lines that
represent the edge
view of the planes of
projection. You can
consider these “fold
lines”.
These planes allows us
to use the characteristics of the lines that
make up each view.
For example…..
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Rule #1:
If a line is parallel to
the Plane of Projection (PP), it will
always be true length
in the adjacent view.
You see that Line AD
in the TOP view is
parallel to PP H. It is
also parallel to PP P
in the RIGHT SIDE
view. Therefore, it
will show its true
length in the FRONT
view.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Rule #2:
If a line appears as a
point in any view, it
will be true length in
the adjacent view.
You can see that line
DC appears as a
point in the FRONT
view. Therefore, it is
true length in both
the TOP and RIGHT
SIDE views.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Here’s how to lay out an auxiliary view:
Step 1:
Make a new PP line labeled
“1” that is parallel to Line
AD in the FRONT view.
This PP (fold line) may be
placed any distance from
the object you wish.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Step 2:
Add the other PP lines as
shown.
NOTE: They DO NOT
have to connect to PP 1.
It is always a good idea to
label the PPs as shown.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Step 3:
Project the end points of
Line AD at a 90 degree
angle (perpendicular)
from the front view.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Step 4:
Transfer the distance
from PP to point C in the
TOP view…
…to its new position from
PP 1 in the auxiliary view.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Step 5:
Connect the new point
C with the projected
line to find point B.
Do the same thing for
points A and D.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Step 6:
Darken your lines in
the auxiliary view to
create its final form.
NOTE: You do not need
to label all points on
your drawing, but it is a
good idea with
complex surfaces.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Auxiliary views may
either show the
“Full” image of the
part….
….or be a "Partial”
view of only the
surface we wish to
view. Usually, you
will only show a
partial view.
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
“Reverse Construction” technique….
This technique uses
points in the principle
views that have been
transferred to the
auxiliary view to create
true shape features. In
this case (because it is
symmetrical), we use
the centerline as the PP
or “fold line”
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
…Another reverse construction application…
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Sketching Assignments
Given two orthographic views of an object,
your task is to create the auxiliary view.
Draw the views at twice size (2x), with each
problem on its’ own sheet of grid paper
Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
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Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
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Week 5: Auxiliary Views
TECH 104 – Technical Graphics Communication
Week 6:
Section Views