You might think utilizing rapid or even virtual prototyping eliminates the need to build fully functional prototypes before heading into production. After all, building a fully-functional prototype takes time and often considerable money, depending on the complexity of the product. It seems once you’ve run all the simulations and worked out any bugs virtually, your product should or could be ready for production. While it may be tempting to follow that route, for more complex products there are elements and conditions that can truly never be predicted by simulations or virtual testing. But even products that are designed virtually and then produced as working prototypes can still run afoul without diligent product testing.
Producing real-life scenarios that expose the demands of a product outside of the lab and that are intended to expose any deficiencies or critical issues of the product as a whole, as well as all of its moving parts, is a critical step in designing a product for manufacturability. Ample testing on a physical prototype should help with the success of the product in the marketplace as well.
Risk Versus Reward with Rapid/Virtual Prototyping
by Dr. Todd Hochwitz
When I started my career many (many) years ago, prototyping consisted of walking paper drawings down to the machinists for them to be turned into reality. Sometimes I had results in days, but more often weeks. However, with the pressures on engineers to operate faster, cheaper, and more efficiently, rapid and even virtual prototyping has become common. Now with the push of a mouse or keyboard button I can have something in a matter of hours or days. That reduction time is clearly an improvement, right?
Sometimes yes, but sometimes no. While it’s nice to be able to see photo-rendered drawings on a monitor, being able to hold something in my hand and get a true feel of the product is better. Having something physical makes the product seem more real, and allows engineers like me to understand nuances of how we’ll actually be able to assemble the item.
However, rapid/virtual prototyping is only one important part of the toolbox. Why isn’t it the perfect fit for everything? There are a few reasons:
- The biggest problem we encounter is that the rapid/virtual prototyping design was made around 3D printing and not actual tooling that is typically used for volume manufacturing. You can easily make a CAD model that can be 3D printed, but that doesn’t mean that a particular design can be molded or stamped or cast.
- Some characteristics of rapid prototyped materials are very different from machined or injection molded versions. While we’ve had great success using printed parts during the development phase, when it comes to some types of testing, they fall short. They may leak, shear, shatter, or undergo different thermal/mechanical behavior than the final versions.
- Simulations are a wonderful tool to quickly invalidate obviously-flawed designs, but they are typically not sufficient to prove a design. The models used, and numerical methods employed, do not always reflect every aspect of the environment that the part will be exposed to. And more importantly, they don’t reflect the unpredictable human element.
One famous such example is the Galaxy Note 7. It was developed in a virtual environment and put through the typical simulation process to expose deficiencies and critical flaws. A working prototype was designed yet, when the prototype of this smart phone went to manufacturing (and then onto the marketplace), it was quickly clear that a significant flaw had been missed in the phone’s battery power source. Clearly, it’s important to not only make sure the product, as a whole, actually works, but to also be sure that all the moving parts are suitable for real-world demands. Not only was this missed flaw a significant safety hazard to anyone using the phone, but a branding disaster. It’s very difficult to undo the damage to the reputation of a product that is infamous for smoking, catching fire, or exploding.
While we do rely upon rapid/virtual prototyping as much as we are able, we always keep in mind the limits of those tools. Using them allows us to quickly get close to a final design as long as we keep the real manufacturing process in mind, and understand the limitations of the models behind the simulations. There are always tradeoffs to consider, corner cases to address, but at Zebulon Solutions, we pride ourselves on being open and transparent with our customers which sometimes means telling them what they need to hear versus what they want to hear. We help our customers work through these challenges to yield a manufacturing-ready product.