Hustler Series: Prototyping Phase

08: Prototyping Phase

Prototyping is a large part of the product design process. It’s a cost effective way to hone in on your final product. And it’s the stepping-stone between the initial design phase and the manufacturing stage.

Prototyping is all about working cheaply and quickly to prove your concept will work. You’ll want to use prototypes as a physical means of exploring every relevant aspect of your product. Prototype everything from the way the product looks and feels to the underlying mechanisms and engineering challenges of the product. You’ll want to validate that the various aspects of your product will come together correctly as intended. By validating all of this through low cost prototypes, you will set yourself up for the least amount of headache when you move on to the final engineering and manufacturing stages.

Prototyping itself has varying degrees of scope but can be broken down into three main categories: form and material studies, mechanism and engineering testing, and detailed mockups.

Form and material studies are used to explore aesthetics. These are very basic, non-functional prototypes that help you hone in on the look and feel of your product. Form studies are used to help you get an idea for the size and shape of your product. Sketching your idea out on paper is one thing, but being able to actually hold it in your hand is a very different experience. For consumer products these are typically made using inexpensive FDM 3D prints. If your product is a piece of clothing or an accessory, you’ll want to work with your manufacturer to have a few samples made. Similar to form studies, material studies focus more on evaluating the finish of your product. This means the types of plastics, metals, or textiles, the colors, and the surface textures. You’ll want to work with your manufacturer to get samples of all these finishes and colors in hand so you’re both operating on the same page. Once you have all these 3D prints and samples in hand you can better evaluate the way your product will look and feel and tweak the design accordingly.

In addition to evaluating the aesthetics you’ll want to test the underlying mechanisms and engineering of your product. This is less relevant for simpler products with no moving parts, but anything that involves engineering problem solving will need to be validated through prototypes. My recommendation is to start by using CAD to design a basic engineering solution to your problem and printing a cheap FDM mockup to test it. The first mechanical prototype is not supposed to be perfect; it’s just something that helps you determine if the underlying solution will work. But once you have a working mechanical solution your goal should be to continue prototyping the design, implementing refinements learned from testing each iteration, and working towards an efficient final product. If your product is electromechanical you’ll also want to use prototypes to test and refine the electrical engineering. Though I’ve collaborated with electrical engineers on a few projects over the years, I’m not trained in electrical engineering myself so I can’t give too much advice in this area. But the general idea is to use as many off-the-shelf components as possible in early electrical prototypes and then move on to having custom PCBAs fabricated once the mechanicals and electronics have been better honed in on.

The last types of prototypes are detailed mockups. These are saved for when the product has been thoroughly refined and are the final means of validating the design before manufacturing. They are essentially production quality one-offs that show you exactly how your product will look and work. For consumer products and electronics this will be an SLS prototype. Selective Laser Sintering (SLS) uses a laser to fuse plastic powder into strong, high-resolution parts. These are then sanded smooth and given the appropriate color and surface finish specified in your concept. This is as close as you can get to your final product without actually ordering injection-molded parts. As for clothing and accessories, you’ll want to work with your manufacturer to have a production-quality sample made. This master sample is what your manufacturer will use for the final production run so make sure you fully approve of the quality, fit, and design.

Cost, as you’d expect, is on a spectrum. Cheap FDMs for form studies and mechanical testing will range from a few dollars to a few hundred dollars depending on the size and complexity of your mockup. If you don’t have access to a 3D printer you can look into services like Fictiv that will quickly print and ship your product to you. Similarly, SLSs will run a few hundred dollars to a few thousand dollars depending on size, complexity, and surface finish. You’ll need to use a professional prototyping service to have these made properly. Apparel and accessories are typically only a few hundred dollars to prototype but this cost may be contingent on you using the manufacturer for the final production run. In other words, the manufacturer may subsidize their prototyping service based on the quantity of products you plan on producing. Due to the price difference between 3D printing techniques, I recommend you use FDMs as much as possible during your initial prototyping phases and save the SLSs until you’ve honed in on a more finalized design. This is the most cost effective and time sensitive approach I’ve found to prototyping.

I’d also like to make the recommendation that you prototype as frequently as you think is necessary. You may find that your initial FDM form studies lack the look you’re going for. It can take many iterations of informed refinements to get your product to where you want it to be. But that’s just part of the design experience. Finding the right voice for your product is no easy task and will take time to hone in just right. But as you become more experienced, or you hire an experienced industrial designer, you’ll become more proficient at honing in on your vision and quickly achieving a high level of quality. However, for newer designers, it’s just a matter of making a lot of prototypes, learning from them, and applying that knowledge to each new prototype moving forward.

For Hez Cases I predominantly relied on FDMs and form/material studies since there weren’t any complex mechanical engineering challenges. My first FDM prototype was used to evaluate the initial slider case design. After determining that this was not the best path forward I tested overmold design options. This meant casting silicone rubber prototypes using FDM molds so I could determine the best durometer for the overmold. Basically I wanted to make sure I had the ideal thickness and stretchiness to the overmold so it felt durable and really locked the phone in place. I then tested various logo sizes and positions as well as case thicknesses and honed in on a combination that felt just right. The case was thick enough to feel protective yet not too thick to feel bulky and the logo was visually balanced on the product. Finally I printed a few FDMs with various raised lips around the front screen. Because the iPhone X uses swipe gestures instead of a home button, I knew it was important to get the height of this lip just right. A tall lip offers more drop protection for the screen but it also gets in the way of gestures. So, after testing a few heights, I honed in on something that was tall enough for great protection but short enough where it didn’t interfere with the user experience. Ultimately I didn’t end up having an SLS made of the product because I was confident in my choice of finishes but, as you’ll see in a later post, this was a mistake. My initial choice of finishes didn’t quite give me the premium feel I wanted for the case so I had to pay to make changes to the injection molds after they were tooled. Using an SLS to evaluate my product before starting the manufacturing would have saved a lot of time, money, and stress. Please learn from my mistakes.

So there you have an overview of the prototyping phase. This is, perhaps, the most important stage of product design. It’s the stepping-stone between the initial concept sketches and the manufacturing stage, and it’s where you’ll really hone in on your final product. Make as many prototypes as you need, learn from each one, and you’ll be on your way to the manufacturing phase.