Exploratory Prototyping Advice from an Inventor

You have an idea, now what? Unless your idea is ridiculously simple, you will probably need to develop it. Almost no ideas come fully formed. They must evolve to approach their final form. Evolution takes place through a process of exploration whereby the inventor plays with the idea and learns. The best method for playing and learning is making a prototype. Making a physical model will often expose overlooked problems and opportunities for improvement. I cannot count the number of times that, in the construction of a prototype, I discovered obvious problems that I had missed. In addition, I discovered many ways to improve upon my idea.

The thought of making a prototype intimidates many people. There are many reasons. The chief reasons seem to be costs, lack of confidence, and the idea that nothing less than perfection will do. The best way to overcome these arbitrary and self-imposed problems is to approach the making of a prototype with the mindset that it is an exploration. It doe not have to be perfect and it does not have to be right the first time. It is an experiment. It does not even have to work the first time. You are probably going to have to make more than one. With this mindset, the costs can be low. Who needs confidence, you are leaning. It does not matter if you screw it up. You will learn something in the process. It does not have to be expensive since it does not have to be perfect.
When I made the initial prototype of my bagel slicer product (see images left), which now sells as the BagelPod Bagel Slicer, I made it out of wood.  The idea was to test the concept. After proving the concept, I moved on to the more expensive fused deposition modeling (FDM) to continue development. Finally, I contracted an industrial designer to improve the aesthetics and manufacturability of the design. The images show the prototypes at various stages of the development work. The wood model looks like something they may have used during Stone Age. The FDM model looks like it came from the middle ages or the set of a Frankenstein movie.

The point is that the first model proved the concept and I found a major problem that I had overlooked. It was completely obvious, in hindsight, and easily corrected. Unbelievably, the wood prototype actually sliced bagels. I was so nervous about testing it that I put it off for days. After I completed the test, and it worked, I had to take a nap. I found myself completely drained of energy. The point is that I started out with low cost methods and found then corrected problems before making prototypes that were more expensive.

There are many ways to make inexpensive prototypes. Sculpting wax or clay is a way to make a model. Tools to sculpt wax or clay are available through online stores and hobby shops.

The carving of wood is yet another way. This is what I did when making my wood prototype. Although this involved the use of wood working tools such as lathes, band saws, etc.


One way to make a mold from the model is using room temperature vulcanizing (RTV) silicone rubber. Sources of the RTV silicone are also online and hobby shops. Instructions on this method are also on the Web. These techniques are relatively easy to learn. Use this to make multiple copies of the initial prototype. Once of course, you are ready to make multiple copies. For example, the prototype is at or very near the finished product stage.

After proving the concept using the cheaper models, the development continues with the more expensive methods. To use these methods you will probably need computer-aided-design (CAD) files. These files are virtual three-dimensional images of the prototype that automated machinery uses to build up or carve out the prototype.

There are two basic methods used to make the prototype. The additive builds up layer upon layer to create the model. In my FDM prototype, a machine sintered (melted) plastic powder together using a computer-guided laser. I provided a CAD file in stereo lithography (STL) format that the machine used as a pattern to build the prototype. I uploaded the file to a Web site and paid by credit card. Three days later, my prototype pieces arrived and I glued them together to assemble the model.

There are many methods available to make a model by the additive methods. The best method to use depends on many factors such as the desired material properties (finish, strength, temperature tolerance, etc…) and mechanical tolerances. The rapid prototyping service I used included consultation in the purchase price of the prototype pieces. I told them my requirements and they advised me on the best method to use.

The second general method to use is subtractive. Here some method carves the prototype out of a block of stock material. The wax, clay, and wood working method are all examples of a subtractive method. Although wax and clay and be either since if you carve out too much you can easily add material.

The use of manual or automated machining tools is another example of a subtractive method. Computer-numerically-controlled (CNC) machining is a commonly used method. CNC is often overkill for most projects. In addition, it tends to be relatively expensive since there are considerable setup costs. Some of the costs are associated with translating the CAD files into a form the CNC machine can use and mounting the stock in the machine.

The methods of making a prototype are not limited to those discussed in this article. It may be possible to make prototypes by modifying commercially available products. For example, gluing toothbrushes together could be one way of making a new type of brush design. The point is that creativity should not be limited to coming up with an idea. It is useful in exploring and developing the idea including but not limited to prototyping. I wish you the best of luck on your explorations.


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One comment so far.

  • [Avatar for Gena777]
    June 22, 2010 09:48 pm

    Great ideas for new and independent inventors. Making a prototype cannot help but improve the quality of a product. An inventor can find out whether or not the invention is worth being patented; and, if it is, how to make it even better. And that helps everyone.