Electronics design engineers are hard-pressed with shortening development time and more complex electronics in today’s industry. Yet, prototyping is still a crucial process to ensure every aspect of the design is fully tested before production commences. In this guide, you’ll learn the different prototyping stages and how to leverage them efficiently to get your product to the market in the quickest time.
Proof of Concept (POC) Prototype
The proof-of-concept prototype is just as the name implies. It is a roughly put-up prototype just to test if the design idea is feasible or not. A POC prototype is often unrecognizable from the final product, as it’s built to validate key principles in the design. For example, you need to build a wireless humidity sensing data logger. While you’re convinced that storing the parameters can be easily accomplished with a Flash chip, there could be uncertainties in wireless transmission functionality.
That’s where a POC prototype comes in. Usually, it’s in the form of off-the-shelf development kits such as the Arduino or BeagleBone. These kits can be integrated with different types of wireless test modules, which allows you to evaluate and select the best solutions. There ought to be minimal design work involved in POC prototyping. Engineers often used existing kits and code libraries to carry out specific tests. A POC prototype intends to minimize cost and save time when evaluating a design idea.
Do you always need a POC prototype?
No. If you’re working on a design where the features are known to work, you don’t need a POC prototype. Still, that’s assuming that you or your team have the know-how and are confident working on the design. POC prototype is only needed when you need to clarify if an idea is workable. Else, it’s best to skip the entire process.
Designing an electronic product isn’t limited to PCB and components. For a product to be marketable, the hardware’s enclosure is equally important. Marketers would want to know what the final product looks like way before it hits the market. That’s where building a looks-like prototype comes in.
A looks-like prototype provides the mechanical structure, form factor, style, and aesthetic of the final product. It is devoid of any functionalities as it’s meant to serve as a visual guide of how the design would eventually look.
However, that doesn’t mean a looks-like prototype has little value to electronic designers. Electronic designers need to ensure that the PCB fits well into the enclosure. The look-like prototype can be used to ensure that the PCB is aligned to the mechanical fittings in the design stage.
Having a looks-like prototype also helps in pitching an idea to potential investors for initial funding. It’s easier to present a product with an easily-comprehensible prototype to non-technical individuals than brandishing a piece of typical PCB.
Building a looks-like prototype used to be an expensive process in the past but not so with today’s technology. There are a couple of cost-effective technologies commonly used in building such prototypes.
The commercialization of 3D printers has made prototyping faster and economical. 3D printing involves an additive process to build objects from filaments of materials. PLA and ABS are commonly used in 3D printing, but you can also build 3D objects from nylon, carbon fiber, wood, metallic, and other unique materials.
3D printing allows designers to produce a looks-like prototype within hours. The process is quite simple once the printer is set up. It involves sending the CAD drawings to the 3D printer, where it was sliced into 2D layers. Then, the object is created by depositing layers of materials based on the CAD drawings.
Depending on the types of 3D printers, the quality and choice of materials may vary. Most 3D printers are based on FDM technology. FDM printers work by feeding the material filament through a nozzle, which was then layered on the printing bed. It’s quick, economical but FDM printing may lack precision and quality.
This brings us to SLA printers, which users laser to cure liquid resin to produce highly precise layers. SLA printers can also work with a wide range of material configurations, allowing prototypes of different textures to be built. Of course, SLA printers are more expensive than their FDM counterparts.
CNC or computer numerical control machining is a subtractive prototyping process. It involves removing parts of a block of material based on the engineering drawings. CNC works with a wide range of materials, including metal, wood, plastic, glass, and foam. It works well as long as the design is not overly complicated.
The success of any electronic product ultimately lies in its functionality. As such, a works-like prototype is a crucial part of the development process. It involves creating a functional circuit that works exactly as what’s specified in the product specifications.
A works-like prototype is very different from proof-of-concept. It is no longer limited to demonstrate the hardware’s functionality by using off-the-shelf development kits like Arduino. As convenient as development kits are, they may not be optimized for installation or operate in harsh environments.
Development kits may also contain redundant parts in the actual application and contribute to unnecessary costs if used as production units. Therefore, engineers need to design a prototype that features all the necessary functionalities while optimizing for cost. Only necessary modules are included in a work-like prototype.
Building a works-like prototype also takes reliability and robustness into considerations. It means that not only the circuit needs to be functional but it must do so under unfavorable conditions. For example, the circuit needs to operate reliably even if it’s subjected to EMI or excessive heat.
Typically, building a works-like prototype requires designing the circuit and PCB layout from scratch. The physical dimension of the PCB is tailored to the actual requirements, along with all the mounting holes. Required components are procured and Shenzhen is the best place to source from. Then, a few pieces of the PCB are fabricated and populated with components for testing.
If the prototype features a microcontroller, the hardware designer needs to work closely with the firmware designer to ensure that all the hardware peripherals are functional. Once the hardware is confirmed to work, the firmware engineer will code and test the remainder of the product firmware.
Developing a works-like prototype is an iterative process, and you may not get it right on the first attempt. It’s important to jot down design mistakes and rectify them in the next revisions. It may take a few revisions before you get a perfect works-like prototype.
Once you’ve got a works-like and a looks-like prototype to your liking, it’s time to put them together. The result is an engineering prototype, which offers both functionality and aesthetic appeal.
You need an engineering prototype for field testing as it has all the characteristics of what would eventually be a production unit. It’s also important to rigorously test an engineering prototype as some problems may not be detected in the lab.
Hardware designers and mechanical engineers need to collaborate closely to produce an engineering prototype. This is especially true when you’re working on smart-wearables, medical devices, or IoT modules. There’s little margin of error between the circuit and enclosure for such products.
An engineering prototype may be field-tested and reliable, but it isn’t good enough for production. You’ll need a pre-production prototype, where both hardware and the enclosure are optimized for mass production.
For electronics hardware, it means ensuring that the PCB is designed for manufacturability. In simple words, the pick-and-place machine must have no difficulty in assembling the components on the PCB. The PCB layout must be optimized with good DFM practices, such as ensuring clear component designators and standardized orientation.
DFM optimization can also lead to cost reduction per unit during production. For example, placing all surface-mounted components on one side of the PCB reduces the pick-and-place cycle. It also means making one solder mask stencil instead of two.
It’s also crucial to ensure that the components are soldered properly by the reflow oven. Footprints must be designed according to IPC standards to prevent issues like dry joints or bridging. These issues can lead to high rejects during QA tests and costly reworks. Engaging experienced PCB assemblers from Shenzhen will spare you many of such production issues.
Mechanical engineers need to ensure that the enclosure is fine-tuned for mass production. 3D printers and CNC machines are great for producing quick mockups, but they aren’t ideal for mass production. To produce hundreds of thousands of units, it is more economical to use injection molding.
Injection molding involves creating aluminum molds to shape molten plastic into distinct shapes. It is, however, not as flexible as 3D printing. Therefore, some easily achieved designs with 3D printers can be an almost impossible feat to replicate with injection molding. Or it could lead to an expensive setup cost that surpasses the allocated budget.
Communication between designers and manufacturers is crucial to ensure the design is optimized for mass production. Ideally, such conversations should take place at an earlier stage to avoid costly reworks for the pre-production prototype.
The importance of prototyping becomes more apparent with changing dynamics in the design industry. Hardware designers could no longer work in silos, and collaboration is key to ensuring a successful product launch.
Our team at ICS Industrial helps ensure a reliable component supply chain from Shenzhen for each of your prototyping stages.