Practical Prototyping. Part 2: 3D
Part 2 of the Series: Cardboard and Foam - Working in 3 Dimensions
Pencil and paper can take you a long way. In this medium you can draw things out just as you envision them, but that can become a limitation. While on paper you can create images and words that describe how something might work, you still need to discover if it will work, and if it does work, how does it feel in reality. Reading that sentence, you may be thinking that there is no way to fully answer these questions without a fully functional prototype. While that is true, we often think we are ready for a full blown prototype long before we really are. Materials like cardboard and foam can bridge the gap between paper, and even higher quality prototypes.
Not Just Cardboard and Foam
While the title of this article suggests I am only going to talk about the two aforementioned materials, there are a really quite a few different options that will allow us to build prototypes of the same Fidelity. When you are attempting to create a prototype of any kind, it’s important to consider what your goals are. Are you only interested in seeing how big your design will be in reality, or do you need to see if a specific feature will work? Maybe you need to know how part of a design feels when your hold it in your hand. All of these considerations will help you decide what level of fidelity you need in your prototype, and what materials might be useful to meet your goals. If you just need to see how big your design is, you can build a relatively low fidelity mock-up, and your material choice is pretty flexible. If, on the other hand, you want to see how a specific feature will work, you may need to choose prototyping materials that will replicate the properties of the final design more effectively, and build a prototype of relatively higher fidelity.
Materials to Consider
Many of us don’t realize how many great prototyping materials are sitting all around us. Two key considerations for materials when building a low fidelity prototype are the cost of the material, and how easy it is to work with. These two factors make a material like cardboard extremely attractive for prototyping. The kind of cardboard that cereal boxes are made out of, for example, is very easy to work with, and replicates the properties of sheet metal very well. One of my engineering professors once said that if you can build it by cutting and folding paper or cardboard, you can usually build it with sheet metal.
Foams can be very useful when your goals are to replicate shape and form. If you are trying to design a new handle for your device, try carving it out of foam. You can use Styrofoam since it’s pretty easy to find for free, but probably the best foam can be found at the hardware store. If you’re looking for high quality prototyping foam, look for the insulation at your favorite hardware store, and find the sheets of insulation foam. It’s not too expensive, and can be easily cut with a hot wire cutter (available at craft stores) or a hot knife (available at the hardware store), plus it’s not nearly as messy to work with.
Since we’ve already considered one material found in the kitchen, what about aluminum foil? It’s very easy to manipulate, and can be purchased in large supply at low cost. Other ideas are disposable plastic cups, popsicle sticks, toothpicks, Elmer’s Glue, and even paper. It may sound like I’m suggesting we go back to our kindergarten roots, and that’s kind of true, but the difference lies in how you approach it. Take time and care in the construction of your prototypes. Think about what materials will best produce the results you are looking for. Remember one of the key benefits of this type of prototyping is that when you’ve created your model, it’s easy to make changes. If you use typical engineering materials and you need to make a change, it’s usually necessary to go all the way back to square one and start over. With many of the materials I mentioned above, it might be as simple as getting out your scissors.
It may seem odd that I have devoted a whole section to duct tape, but it truly is one of the most useful prototyping materials. Think about all of the people you have heard of, or even know, who have created wallets, purses, shoes, or even entire outfits from duct tape. This should make it pretty clear that the flexibility of duct tape as a prototyping material is very high. In my own experience, duct tape has been used to replicate everything from straps of Velcro, to plastic sheets, to layers of fabric. Duct tape is quick and easy to use, and even comes in different colors, to help you distinguish different features of your design.
Look for Analogs
When prototyping, don’t re-invent the wheel. If you want to see how a specific feature will work, look for an analog product that incorporates this feature. Study how it works, how it is made, and try to learn as much as possible from its design. It’s highly likely that some engineer or designer spent many hours trying to design the best way to accomplish the same goal you are working towards. After you have learned from the work of others, go back to your design, work for awhile, and then examine the analog product again. It’s likely that your own design experience will help you appreciate some features of the analog product’s design even more.
Do it All Over Again
You won’t stumble onto the perfect design the first time. If you get to the point with cardboard and these types of materials that you feel like you are stuck, go back to paper and pencil. Identify the problems you still need to overcome and work on them individually. Push your design on paper again, and then prototype with these low fidelity methods. Keep repeating this loop until you can’t learn any more without increasing fidelity. When you get to that point, you’ll be ready for the next article in this series Tougher Materials - Wood and Steel.
Adam has a Bachelors in Engineering Mechanics from the University of Illinois Urbana-Champaign and works for IPT as the Director of Engineering.