Prototyping Early for Success

Sometimes, as student engineers, we look at a design problem and our brains jump immediately to how we will analyze the project.  Think about it.  When you first started your project, one of the first things you thought about was which parts you could stick into an FEA, if you would have to do a fluids analysis, or how in the world would you choose an engine if you don't even know how to analyze it.

Well, it turns out that this reaction is pretty common.  This is largely due to our education, which emphasizes a blend between hands-on and theoretical work.  The problem is that the first time we encounter a design project, we want to define it fully in the theoretical domain before we feel comfortable moving on.

But there is a new paradigm that is starting to change the engineering field.  Our friends over in the industrial design department have already known this for years.  It is to prototype a lot, and prototype early.

A "looks like" prototype for a concept brick

Now, let me clarify what I mean by prototype.  A prototype can range from a bunch of post-it notes describing how your user will interact with your project to a fully functional race car.  In between we find all sorts of interesting things like cardboard mock-ups, wooden models, rapid prototyping, sketches, and so on.  In general, there are two types of prototypes: "looks-like" and "works-like".  Both have very specific purposes and are very useful.  As the design process continues, these two types of prototypes converge into a single prototype that is fully functional and also embodies the final form.  The thing about prototypes you have to remember is that the point of a prototype is to communicate.  It is to communicate ideas, whether they be visual or functional ideas doesn't matter.


So, let's talk briefly about what the two types of prototypes are, how they are used.  In future posts, we'll cover when various prototyping methods are appropriate, and the concept of low and high fidelity prototypes.
"Looks-like" - This is a prototype that focuses on the form of the design.  It may have some working parts, but the point of this prototype is to convey shape, feel, and a lot of the "soft" stuff that engineers often ignore.  It may seem that these are mostly useful for consumer products, but not so much for something more technical like an assembly-line robot.  False.  Even building an extremely simple layout from cardboard boxes will reveal problems with neighboring machinery or give an idea of the ballpark dimensions needed to accomplish the task.  These prototypes help you identify functional problems and relational problems with your design.  You will never know what you will learn by building a prototype, so it is easy to overlook the importance of it.  Examples may include CAD models, Lego models, cardboard mock-ups, sketches, or anything that may convey the shape of the design.

A "works like" prototype for a linear spring

"Works-like" - This is a prototype that focuses on one or more of the functions of the design.  It may incorporate some of the final shape, but its point is to prove that a particular technology will work and work well.  Often, early "works-like" prototypes will only demonstrate one part of a system, such as the power train on your alternative energy vehicle or the door mechanism on your automatic mailbox.  These may not include any parts from the actual vehicle or the mailbox; just the mechanisms.  These prototypes help you identify technical problems with your design early on.  Like "looks-like" prototypes, build these early and build them often.

To give you an idea of what it means to build them early, you should start prototyping as soon as you have a concept selected, maybe earlier.  By your first design review, you should have several mock-ups that your reviewers can see and hold.  It doesn't matter if it's elegant or well made.  The point is that these prototypes communicate the ideas you have and have the added benefit of validating your assumptions.

Well, that's all for today.  Later, we will deal with low and high fidelity prototypes.  Good luck designing!