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14 CHAPTER 1 INVENTOR DESIGN PHILOSOPHY

The emphasis is on designing and building something quickly and economically, without

sacriﬁcing quality or performance. Many companies today specialize in custom machines and

automation where the ‘‘prototype’’ is the end product. Clearly, anything you can do that reduces

or eliminates prototyping will greatly inﬂuence your ﬁnancial health and competitive strengths.

What Is a Virtual Prototype?

Over the years, as designs tools have evolved, so too have the ways we design. However, it is

possible to use new design tools in the same manner we used the old tools if we are not careful. As

companies moved from the drafting board to AutoCAD, many users continued to use AutoCAD

in much the same way they used the board. Not reusing data in the form of blocks and block

libraries and not employing block attributes to pack those blocks with intelligence are a couple

examples of this.

In much the same way, it is possible to use Inventor like it is AutoCAD. Creating 3D models

simply for the sake of generating a 2D shop print is a common example of this. To ensure that

you are getting the most out of Inventor, you want to ensure that your designs are more than 3D

models and are in fact virtual prototypes.

So, what is a 3D virtual prototype? Put simply, it’s a digital prototype that has not yet been built.

And although that simple answer seems obvious, it is the ‘‘not yet built’’ part of that description

that is key. A virtual prototype is a completely digital 3D parametric model that functions the

same way a real mechanism should.

The virtual prototype consists of a main assembly, containing many subassemblies, containing

individual parts. All these components are constrained in such a way that ﬁt, and the functionality

of all parts and mechanisms can be visualized, tested, and proven before any parts are manufac-

tured. Scrap and rework are virtually eliminated if the design is fully completed and proven in the

digital form.

Making the virtual prototype allows the designer to explore the function of a mechanism before

lengthy design and engineering time is expended on a design that just won’t work. Developing

the virtual prototype eliminates the part procurement and creation process, slashing the design

time even further.

The virtual prototype can be proven with the use of stress analysis and dynamic motion sim-

ulation to ﬁnd and correct weaknesses in the design, rather than just ensuring that everything is

overbuilt and calling it a good design. Interference between components is also easily discovered

while still in the design process.

The use of functional design in the prototyping process allows engineers to properly determine

loads, power, stresses, inertia, and other properties before a machine is built. Weights, center of

gravity, and other physical characteristics are at your ﬁngertips during any stage of the design.

Sean Says: Take Full Advantage of 3D

When I ﬁrst looked at Inventor release 1, I had no idea how much it would change the way we

designed machinery. We had been using Mechanical Desktop for a few years, but it was not until we

were introduced to Inventor that we really realized the full potential of 3D design.

Looking back at some of our old AutoCAD designs, I wonder how we did it. All of the lines just lie on

top of one another in one big messy dimension. To this day, I still try to orbit 2D AutoCAD drawings

thinking (hoping?) they hold some hidden 2.5D information.

In this day and age, there is no reason why you should not be designing in 3D. One of the most obvious

beneﬁts you’ll immediately see is simply the aspect of visualization. Now you can easily see that shaft