A rapid prototyping primer: From Batman's belt to a hardware revolution

Rapid prototyping means more innovation on the hardware side. But inventors and entrepreneurs need to take a holistic approach to reap the benefits of the technology, says one expert. Here's why.
Written by Greg Nichols, Contributing Writer

My recent post about the dawn of the hardware startup generated some great reader emails. Many of the responses concerned rapid prototyping. The concept is no doubt familiar to readers of ZDNet, but the nuances and evolution of the underlying technologies and processes may not be.

Since rapid prototyping is becoming central to the new hardware startup paradigm, and the impact on robotics in particular will likely be huge, I turned to Dr. Martin Culpepper, a professor in the department of mechanical engineering at MIT and an expert on the subject. Dr. Culpepper is gearing up for a new course on rapid prototyping technology at MIT Professional Education, one that emphasizes a holistic approach to educating engineers, entrepreneurs, and inventors, and that makes him an excellent resource to help unpack the subject.

GN: Let's start with an example of a group you've worked with and use that to frame the conversation. Give me a project that wouldn't exist if it weren't for this technology.
Photo courtesy of Atlas Devices

MC: One of my favorite examples is a group of undergrads and graduate students that built a winch just like the one on Batman's belt. They came up with this clever idea of how you would engineer the device. They figured it would be useful for troops, and you can envision in places like Afghanistan needing to climb down walls or cliffs to look in a cave. But once you look in, there might be an instance when you want to get out of there in a hurry. So that's what they built. They

had the idea, physics said it should work, they built a prototype, and it didn't work. When they tested it, it just wasn't right. So they built another prototype and then another and another. Eventually they had something, and they started a company.

GN: Awesome, I want one. Let's get basic. What are we talking about when we say rapid prototyping?

MC: Rapid prototyping is a group of technologies and a group of processes. Basically we're talking about machines you can use to make things rapidly. Many people think of 3D printers, which is one example. There's also CNC [computer numerical control] milling and lathe work, which you can use to make sophisticated metal and plastic parts. And there are laser cutters and water jet cutters. Lasers rapidly cut two-dimensional components from polymers and water jet cutters are used in polymers, wood, ceramic, and metal. You have CNC routing for wood and plastic. And now there's also the ability to do electronics work. If you need to make a custom circuit, we have that ability, that's available.

GN: What's the impact on innovation?

MC: The analogy would be taking away laptops except for a few special cases. That would bring innovations in software to a screeching halt. We have the reverse of that in mechanical prototyping because not everyone understands or has access to prototyping systems. But that's changing. Impact-wise, at least on campus for us, rapid prototyping is going to cut design and build time by a factor of 10 to 20. I expect it's the same for companies. The other thing that's happening at companies is that once you get rid of those barriers to manufacturing, engineers start to have a better sense of how stuff actually gets made, how it's produced. That allows them to make better design decisions. So it's not just the speed, but it's connecting those engineers to the production process.
Roland DGA rapid prototyping machine

GN: So it's a totally new paradigm in which products are conceived and designed. I often hear people talking about rapid prototyping as a panacea, a magical new tool that's really going to change everything. Is that accurate?

MC: Well there's a sense that you push a button and out pops whatever you want. In reality, that process might take weeks of design and implementation work, and that's not rapid, that's regular engineering. In fact, just access to this technology might make prototyping times worse. The key is a holistic approach that takes all parts of the process into consideration. There is a general way to go about good engineering design and rapid prototyping, and you really need to have a handle on those principles. If you do, you can apply that framework to new rapid prototyping technologies when they come up. That's what I'm teaching in my new class, an approach that won't be constrained by any particular technology. It's a combination of software, best practices, and tools that allow you to go from an idea to having the thing in your hand quickly.

GN: And what's the difference between that thing in your hand and a finished product? Or is that difference disappearing?

MC: Volume is the differentiating factor. If you need 50 units of something, 3D printing is an attractive solution in itself. If you need a million units, and you're talking about plastic, then injection molding is the way to go.

Depending on the technology you're talking about, there are always strengths and weaknesses. There's always a tradeoff. With 3D printing you get tons of flexibility, you get speed, but to a large extent you won't get something that's strong or durable. The real advantage comes in terms of fixing a targeted problem. With rapid prototyping you can fail fast, and then try and fail until you succeed. That's where the innovation comes in.

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