The iPhone Duo is now in our custom foldable phone testing machine. Will it beat the Galaxy Z Fold 8?

We want to know how many times you can bend an iPhone Duo before it breaks. After waiting more than three hours at the Apple Store on Friday, we purchased one of the coveted iPhone Duo foldable phones in Louisville, Kentucky, and took it back to CNET’s lab, a custom-built facility where I oversee hardware and software testing as director of lab operations.

The goal is simple. On Friday afternoon, my team and I loaded the iPhone Duo into a proprietary machine we built to test foldable phones like Apple’s. and Samsung’s rival, the Galaxy Z Fold 8, which we have already started essay. I oversaw the methodology and construction of this testbed for months in anticipation of Apple’s long-rumored foldable iPhone. (Read on to find out how CNET tests foldable phones.)

We even named our machine based on its purpose: Meet the Fold a phone.

From now on, my team of engineers and testing experts will monitor the opening and closing of the iPhone Duo, to rigorously and systematically monitor the durability of Apple’s hinge and dual displays.

After all, bending a phone repeatedly with your bare hands can only go so far in helping you understand the complex forces at play between the magnetic elements that close the screen and the all-important hinge.

CNET Senior Technology Reporter Abrar Al-Heeti did a great job capturing the pros and cons of the iPhone Duo in her smart, in-depth review. Our Fold-a-Phone machine will add an in-depth database to complement its real-world experience.

Since Apple hasn’t publicly shared claims about the iPhone Duo’s foldable lifespan, CNET’s Fold-a-Phone machine is poised to provide a wealth of valuable data on Apple’s first foldable phone and competing models in the foldable market.

And yes, you better believe we’ll be using our trove of internal data to share status updates and comparisons during our ongoing testing window with the Duo.

Join CNET’s iPhone Duo live stream on YouTube Monday from 1-5 p.m. ET, where you can follow along live and ask questions about our iPhone Duo testing process.

It is difficult to overstate the importance of this moment. Apple’s arrival on the foldable smartfold frontier lags Samsung by seven years (the first Galaxy Fold went on sale in the United States in September 2019). Motorola and other phone makers have long experimented with foldable phones of all shapes and sizes, including a tri-fold accordion foldable phone that we first demonstrated in 2019.

Matthew Murray/CNET

CNET’s mobile experts, including Al-Heeti and editor-in-chief Andrew Lanxon, discussed the legitimizing effect of the iPhone Duo’s existence on the entire foldable phone landscape, which previously felt like a new wave fantasy rather than a mainstream one.

In many ways, Apple’s new competition with existing foldable phones rounds out the portfolio. This is precisely why we’re building the Fold-a-Phone now, and why our machine, methodology and proprietary testing data will enrich our collective understanding of the capabilities – and yes, the limitations – of foldable phones as a true next-generation mobile device.

How CNET’s Fold-a-Phone tests foldable phones like the iPhone Duo

Most current foldable phones are rated for 200,000 to 500,000 folds. As such, we knew we needed to create a robust and adaptable machine capable of supporting foldable book and flip phones of all sizes, dimensions and hinge orientations. (Note: Fold-a-Phone was not designed for tri-fold phones, which represents a unique element of the technical challenge.)

Additionally, we wanted to test the phone how people would actually use it. No one sits around opening and closing their foldable phone at full speed all day. Rather, you open it naturally, spend a few minutes watching a video, browse a web page, or use an app, close it, then put it in your pocket. This can happen dozens of times a day.

Mimicking this usage on the Fold-a-Phone limits excessive stress on the phone’s hinge and avoids generating excess heat compared to a test designed for speed.

We determined that a cadence of around 4 seconds could bypass technical obstacles and still be reasonably fast. The foldable phone takes 1 second to open, 1 second to fully open, 1 second to close, and 1 second to fully close. This cycle counts as one completed fold. Then the cycle repeats until the hinge or screen gives way.

When conceptualizing and building the Fold-a-Phone, our team used off-the-shelf, off-the-shelf components to simplify the development of the machine. The essential design consists of two frames, distinctly designed to perform the opening and closing movements with strength and grace.

Matthew Murray/CNET

An industrial-grade stepper motor drives each armature, with the host software (running on a connected computer) adjusting torque deterministically to complete each step of the process while protecting the phone. If one of the many proximity sensors fails to detect the armature in the correct position, the machine stops immediately.

We also monitor the power consumption of the motors to track the opening and closing of the foldable phone over time. We have installed cameras to capture images and videos of the test from multiple angles, and we will analyze regular computer status updates to determine the current status of the phone and the test.

To ensure we never miss a major development, the entire platform is connected to an EcoFlow Delta 3 Plus power station to guard against power outages, and all output data is recorded in multiple locations.

To secure each phone to the machine, we use our CNET Lab Test-winning 3D printer, the Prusa Core One, to 3D print a custom “sled” that matches the exact dimensions of each phone. We attach the phone to the sled with heavy-duty double-sided tape (yes, it works!), then screw the sled onto the machine.

There is always room for improvement. We are constantly looking for ways to make the machine smoother and quieter without disrupting the rhythm of folding.

Apple’s presence is already a game-changer and could very well spur innovation in ways we can’t predict today. But until then, our Fold-a-Phone machine will continue to test the iPhone Duo and its competitors, and CNET writers will report on how these individual articulated devices hold up to the challenge — or bend under the pressure.

Matthew Murray

Laboratory Director

As CNET Group Lab Director, Matthew leads the Labs team, which helps coordinate and conduct product testing for CNET and other Ziff Davis editorial brands, including PCMag and ZDNET. He previously spent eight years as head of testing at Future plc, and before that eight years as an analyst and editor at PCMag. His technology writing has also appeared in publications such as Computer Shopper, ExtremeTech, Tom’s Guide, Laptop, and Backstage.

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