Figure 1
– The concept of degrees of freedom and corresponding terms. Our objective is to
eliminate degrees of freedom. For the time being, think of degrees of freedom in terms of
Murphy’s law, e.g., as things that can
go wrong. |
Figure 2 – A complete multiview drawing specifies everything
required to create
the part to a given standard of quality. Besides the six basic degrees of
freedom illustrated in Figure 1, there are a multitude of additional “manufacturing”
degrees of freedom we must remove. The science of eliminating these
manufacturing degrees of freedom
is
communicated in the language of dimensioning
and tolerancing. |
Figure 3 – As a small initial step, we start by defining DATUMS. |
EXERCISE 4-1: Reproduce the
models on P.159 13-21 and create working drawings of them with Datums and
Dimensions. (Use the graphs to determine ratios)(Also, use primitives as much as
possible to create the shapes.) You will assign the 3
Datums, Primary-Secondary & Teritary, to appropriate surfaces of each
model, and assign geomentric relationships using Feature Control Frames. Save
all files in the Q: and Print out each working drawing. You will need the little reference book for
Geometric Tolerances |
Exercise 4-2: Create a presentation
view of your Composite Model of last week. Save it as a .jpg and place it on a
22 x 34 layout in PowerPoint.
Save all work on the Q:
Drive.