Getting a prototype to function is a huge milestone.

But most people assume that once the prototype works, they're ready to manufacture.

They're not.

And finding that out after you've paid for tooling, placed a factory order, or started certification testing is one of the most expensive surprises in hardware development.

A working prototype only proves one thing: that one or two boards work like they're supposed to in a controlled environment.

But a factory is building thousands or hopefully millions, and every unit comes out a little different.

Component tolerances stack up, solder joints vary, and the units at the edges are where the problems show up. That's a completely different challenge than getting one or two boards to work.

So there are at least five gaps between "it works on my bench" and "it's ready to manufacture."

Can it be manufactured consistently?

Your prototype was hand-assembled, maybe with tweaks and little workarounds you didn't even write down.

A factory has to build thousands of these with no tweaks at all.

So your layout needs to be designed for automated assembly, your components need to be available in production quantities, and your tolerances need to account for the natural variation in a factory.

A design that works when you carefully solder one board can fail at a 5% rate when a machine builds 5,000.

Can it be tested at scale?

You tested your prototype by poking around with a multimeter and watching it run.

A factory needs to test every single unit in seconds.

So if you haven't designed in test points and planned out a test procedure, you're either shipping untested products or paying someone to manually check each one.

Neither of those ends well.

Will it survive the real world?

Your prototype sat on your desk in a temperature-controlled room.

The production version might sit in a hot car, get dropped, run around the clock for years, or operate in humidity you never tested for.

I learned this one the hard way with my own product.

I shipped a 3D printed prototype to a buyer at a major retailer during a summer heat wave, and the resin I used couldn't handle the heat.

It warped just enough during shipping that when he finally tried it, his only feedback was that it felt awkward to use.

The thing worked perfectly on my bench, but it failed the moment it left my controlled environment.

Reliability problems don't show up in prototyping, they show up six months after customers have your product.

Can it pass certification?

Whatever your product needs, FCC, CE, UL, or some mix of them, none of it is just a formality.

Designs that weren't built with certification in mind regularly fail their first round of testing.

So that means redesigning, re-prototyping, and retesting, a cycle that can add months and tens of thousands of dollars.

Can you manufacture it at a profit?

Your prototype proved the product works, not that you can manufacture it at a price that leaves you enough profit.

And your real cost is a lot more than the parts, once you add assembly, the enclosure, testing, scrap, duties, and shipping.

Most people don't add all that up until production is ramped up, and by then it's too late to change the design.

So you should instead design toward your target cost from the start, working backward from the price it has to sell at.

None of these are things you'd naturally think about when your prototype just powered on and worked perfectly.

And that's exactly what makes them dangerous. The problems stay invisible until they're expensive.

You can work through all of this yourself if you know what to look for.

You can also hire an experienced engineer, but you want someone independent from whoever designed it, and someone who's actually taken a product through manufacturing, certification, and scaling.

Inside the Hardware Academy, our engineers review your design for these exact issues as part of your membership.

It's always a lot cheaper to catch them on a screen than on a production line.

Talk soon,

John Teel
Predictable Designs