There are a lot of technologies at your disposal to create a prototype for your new hardware product. These technologies can be split into two broad categories. The first category consists of methods to prototype the electronics portion of your product. The second category includes the various technologies to prototype the product enclosure. Begin with the simplest, cheapest way to prototype your product. Learn as much as possible from it, then strive towards a production quality prototype with every iteration. In this article you’ll discover nine of the most common prototyping methods available and what you can learn from them.
#1 –Electronic Development Kits
Development kits are great when you need to prove the functional concept for your product. Making a proof-of-concept (POC) prototype, using development kits like an Arduino or Raspberry Pi, is a good place to start for many products. This is especially true if you have big questions about how your product will solve the intended problem. Development kits, sometimes called development boards, are also a fantastic way to learn more about electronics. However, development kits have some important limitations to consider. Most kits are too large and expensive for mass manufacturing. Eventually you’ll need to migrate to a custom electronics design.
#2 – Electronic Modules
Electronic modules have the advantage of being small and cheap enough to integrate into other systems or products. Electronic modules perform specific functions and are usually soldered onto a Printed Circuit Board (PCB). Modules are especially useful in the case of wireless functions. You can use wireless modules to reduce the development cost and risk, while also lowering the cost for elec-trical certifications. Modules also help bring your product to market more quickly.
#3 – Printed Circuit Board (PCB)
There are two steps to producing a custom Printed Circuit Board (PCB). First, a bare PCB is generated without any of the electronic components. Second, all of the electronic components are soldered onto that PCB. You will probably have to outsource the production of your PCB prototype since only the simplest designs can be produced at home. Fortunately, this same process is used to manufacture PCB’s at high volume. This will greatly simplify the transition from prototype to mass manufacturing for the electronics.
#4 – Foam / Clay
Foam and clay are some of the lowest tech materials you can imagine. But don’t discount these simple materials. They can be an inexpensive way to think through issues such as product shape and size. Simple materials like foam and clay allow you to quickly create crude, looks-like prototypes for almost no cost. Foam and clay help you experiment with how your product feels in your hands. Once you work out the simple design choices, then you can move on to more advanced technologies.
#5 – Fused Deposition Modeling (FDM)
There are three prototyping technologies that all fall under the name “3D printing”. The most affordable technology is called Fused Deposition Modeling (FDM). This is the most commonly used technology for low-cost, home 3D printers. As with all 3D printing technologies, FDM is an “additive process” since plastic is added layer by layer to build up a prototype. The plastic is heated as it passes through a nozzle. Once melted, the plastic is deposited in layers which then fuse together. The downside to FDM is they can’t reproduce fine details, and ultimately the prototype won’t have the quality and appearance of more expensive 3D printing technologies.
#6 – Stereolithography (SLA)
In most cases, stereolithography is your best technology choice for producing high-quality, complex prototypes. The tradeoff is that SLA printers are considerably more complex and expensive, costing at least several thousand US dollars. This limits their use primarily to professional prototype shops such as Seeed Studio. SLA is an additive process just like with FDM. However, SLA printers cure the resin using ultraviolet (UV) lasers. This liquid resin is added layer upon layer and hardened by light. This process is called photopolymerization, and can accurately produce fine detailed prototypes. Stereolithography prototypes are also very strong due to the chemical bonds between each layer of resin. SLA prototypes also have a more professional appearance than those produced by FDM.
#7 – Selective Laser Sintering (SLS)
Selective Laser Sintering is also an additive process grouped under 3D printing. However, SLS printers use lasers to harden powdered material one layer at a time. SLS printers are too complex and expensive for home use. The big advantage of SLS technology is that it can be used to produce prototypes made out of metal in addition to plastic.
#8- CNC (Computer Numerical Control) Machining
Fundamentally different than the three additive printing methods I’ve already discussed, CNC machining is a subtractive process. CNC machining begins with a solid cube of plastic or metal. Material is then precisely removed (i.e. subtracted) by computer controlled tools to form the desired shape. This process is very similar to a sculptor carving a statue. CNC machining isn’t nearly as common as 3D printing, but it can have several advantages. First of all, parts can be created from either plastic or metal. Secondly, the parts produced are stronger since multiple layers aren’t merged together as with additive printing. Finally, CNC machined prototypes can use the same plastic as will be used for high volume injection-molding production.
#9 – Injection Molding
Eventually you will migrate to producing your plastic parts using injection molding technology. Injection molding is the only option for producing plastic parts in high volume production. For injection molding you first need to create a mold made from metal. This mold is created using the CNC machining process we already discussed. The mold consists of two halves which are forced together to form a cavity in the shape of your part Melted plastic is then injected into the mold at high pressure. This pressure allows an extremely high level of fine detail in your plastic part. Although primarily used for mass manufacturing, injection molding is your only option for creating a prototype that will be identical to your final production units. To save money, start with lower cost aluminum molds for making several thousand parts. Then, migrate to molds made from harder steels as your manufacturing volume ramps up. Conclusion I hope you’ve gained an understanding of all the prototyping choices in front of you. My general advice is to begin with the simplest, cheapest methods possible. Learn as much as you can, then move on to more advanced prototyping technologies.
Author Bio: John Teel is the founder of Predictable Designs which helps startups, makers, and small companies develop new electronic products. Previously, John was an award-winning design engineer for Texas Instruments (TI). While at TI he designed many successful microchips which are found inside popular tech products (including some from Apple). John also launched his own hardware product which was sold in over 500 retail stores in three countries. You can download his free cheat sheet – 15 Steps to Develop Your New Electronic Hardware Product.