Product Development Process




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Product Requirements
Prototypes

Links for further reading:
Process Overview
Step 2 - Requirements.
Step 3 - Information & Planning.
Step 4 - Design.
Step 5 - Prototypes.
Step 6 - Production.
Process Notes
When to Patent

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Step 5 - The Purpose of Prototypes:
Prototyping is the design verification phase of Product Development -- used to demonstrate or prove aspects of a design. Prototyping is simply taking the design from the virtual, imaginary realm into the physical world.
There are many levels of Prototypes:

Some are simple duct-tape and bailing wire types to visualize how something might work;

Some are highly polished, fragile representations for show and tell;

Still others are functional representations that work, but may not look perfect;

And some are complete representations of the final product.

The type of prototype chosen should fit the specific needs of the project or tests -- especially since there is often a significant cost involved.
Typical prototyping methods include mock-ups (clay, wood or other), fabrication, and rapid prototyping. Mock-ups are typically done very early in the design for visualization, feel, and to allow adjustments or fiddling with shape and size. Fabricated prototypes are typically functional versions that may or may not look like the final product but give the opportunity to test function or prove something works.
The term "Rapid Prototyping" encompasses a large group of technologies that create 3D physical parts directly from the computer. This is becoming very popular because of the speed and accuracy available. These can be done in almost any shape and can be finished to look exactly like a production part -- though usually much more fragile. A whole host of service bureaus have sprung up to meet this need, so for more information, a quick web search will usually yield an overload of information.
. . . . Regardless of the method, prototypes should be thought of as tools: for learning, for visualization and for design improvement . . . .

Before diving into the prototyping phase, there are few questions to ask:

Is a prototype desirable or necessary?

Is there a need for design verification?

Is testing needed for design improvement?

Has the design been done to the best knowledge before prototyping?

Depending on the product, a prototype may or may not be necessary -- or perhaps more importantly, it may be that only parts of the design need prototyping. This is not to say that prototypes should not be built, just to emphasize that prototyping is costly in both time and money so the need should be evaluated.
In many industries the products are quite complex and require several iterations of design, prototyping and testing. The auto industry, for instance, uses several variations of prototypes to evaluate the design and to find areas of improvement. In the case of automobiles, the complexity of the design and the amount learned in testing from each version easily justify the time and cost.

A Note About Testing

What do you test? How much testing? What kinds of tests?
Most industries have standards to meet or requirements to satisfy. Certainly testing must be done to certify or "pass" those tests, but don't forget testing for your own benefit . . . testing to verify your FMEA (Failure Mode Effects Analysis). Every product has some possible failure point. It may be in abuse or something else, but because it can fail, you must understand it. Testing to verify failure effects is extremely important.
Test with an open mind. Testing should be done as realistically as possible, with a mind open to learning everything available. If something unexpected happens, you've learned. If something breaks, it does not mean you failed, it means you've learned, and you're that much closer to a better design.
Don't skip or short-cut the testing. Field failures come back to bite -- usually with very large teeth!

A parallel process to be done with prototyping is Production Quotation. This is where manufacturer input is requested -- both for cost to produce as well as for ways the product can be made cheaper, easier, lighter, faster, stronger and better. This is especially valuable if the design is to be iterated, and can influence your needs in prototyping.
In practice, most products require at least one prototyping phase. Typically, the flow is from the design phase to prototype and testing then back to design for (hopefully) minor changes before going to production.

Prototyping (our Speaker Example):

The first speaker prototype turned out really good so a matching prototype was also made and both are in use. A few improvements for ease of assembly were identified, so some minor changes were made in the design before the plans were put up for sale in our Buy the Way section of this web site.

Concluding Thoughts ...
Really, the Design and Prototyping steps of the Product Development Process can be blurred together with learning and insight coming from all these tools. Also, the final stages of both design and prototyping (especially the final stages) should include input from manufacturing.
Whatever the product, if it is to be sold, it will need to be produced, and that involves the next step of manufacturing. Our experience has taught that involving possible manufacturers early in the design phase and especially through the prototyping phase makes the transition from design to production much easier, faster and smoother.

Continue to Step 6 - Production Details and Production.