Microsoft has brought me inside the Surface hardware lab from time to time over the years, showing me how its engineers test the hinges and fabrics that go into its products. They’re usually typical engineering demonstrations, but last month I was invited to Microsoft’s headquarters in Redmond, Washington, to see how the company built its two new smaller Surface Pro and Surface Laptop devices. And this time around, I was pleasantly surprised to be shown how Microsoft uses magnets, robots, drop tests, and smoke to perfect its laptop and tablet designs.

The first stop on the tour led me inside Microsoft’s advanced prototype center, where Surface engineers are constantly creating prototypes to refine the fit and finish on a new product like the Surface Pro 12-inch. One of the new challenges for this device was getting the Surface Pen to attach to the rear of the tablet — and stay there.

Microsoft wanted the stylus to attach with one hand but still be tough enough to stay in place when you slide it into a backpack. Engineers designed different magnet combinations, then tested their effectiveness with machines that record the force and distance needed to remove the pen. The team then tweaked their tests and designs to make sure there was a consistent feel on every single Surface Pro.

This same testing is used for the hinge design and magnetic keyboard. Microsoft has created a variety of tests to measure pass and fail rates on prototypes of keyboards to make sure they can attach at multiple angles. That’s particularly important on a smaller keyboard, and it’s something I’m going to be testing myself when I review the Surface Pro 12-inch.

Microsoft has also been obsessing over performance and battery life on its Qualcomm-powered Surface Laptop devices over the past year, touting them as MacBook Air killers. While the new Surface Pro has moved to a fanless design, Microsoft is sticking with a fan on the new 13-inch Surface Laptop to help cool the chips inside and provide competitive performance. As there’s a fan inside, Microsoft has had to simulate airflow through the cooling system to ensure its prototypes are hitting their targets without throttling too soon.

Surface engineers use smoke to do this, much like how a number of PC gaming YouTubers demonstrate the airflow of modern case designs in the same way. Smoke gets pumped through the intake vents and outputs through the rear to show where the airflow might be getting blocked by a part of the device and not performing as optimally as possible. Airflow is even more important on a smaller device, where the thermals are more constrained.

Once Microsoft’s engineers are happy with the level of cooling, the fan prototype then gets tested inside a thermal chamber. The temperature is set to 35 degrees Celsius, around 95 Fahrenheit, to see how well the fan and cooling performs at this kind of heat. Microsoft measures areas like the palm rest part of a laptop to ensure they’re staying within the thermal limits and that the device is still comfortable to use. Engineers also look at hot spots with FLIR thermal imaging cameras to ensure the laptop isn’t overheating anywhere.

Precision thermal and Surface Pen tests are interesting, but they’re not as much fun as good old-fashioned real-world violence. Microsoft showed me how it experiments with its Surface devices by dropping them and smashing them up. I haven’t seen a drop test on a Surface lab tour since the early days of Microsoft’s tablets, so I was pleased to see the company was brave enough to attempt one again.

A drop chamber is designed to validate Microsoft’s simulation data against the reality of dropping a device on concrete flooring. The drop chamber was key to developing Microsoft’s removable battery packs on its latest Surface devices, for example, to ensure any drops wouldn’t puncture the batteries.

Microsoft says that dropping its Surface Pro 12-inch from a height of two meters onto a hardwood floor does not cause any significant damage, but when it demonstrated the same test on a concrete floor it dented in front of my eyes. It was still functional, but part of the chassis had buckled under the pressure of the concrete. A few years ago I accidentally dropped a Surface Pro review unit in a similar way and the screen cracked, so hopefully these drop tests mean the latest model is even sturdier than before.

When Microsoft isn’t busy dropping Surface prototypes, engineers also zap its tablets and laptops with electrical discharges. This ensures you don’t have any weird experiences with electrostatic discharges that could lead to software crashing or even a USB port failing. Microsoft tests above regulatory limits to make sure that extreme scenarios won’t kill its hardware. The company also has a special radio frequency chamber to test frequency interference in a sealed room.

My favorite part of the Surface labs tour was seeing Microsoft’s robots in action. The company has robots set up to tap the screens of its Surface prototypes 8,000 times to ensure the whole touch panel works every time and no touches are misregistered or inaccurate. The robot can even change the tool used to tap a screen to simulate different finger shapes.

One room where I was led was full of robots, small and large. In the corner a larger robot was busy swiping away on a Surface screen to test that gestures work correctly. A few steps away another one made me smile while using the Surface Pen to draw. As it was Microsoft’s 50th anniversary, a robot arm was drawing a doodle to celebrate the company’s milestone. Smaller robots in the same room were testing palm rejection and tilting with the pen. If the robots ever do rise up, I wouldn’t want to be working in this room, that’s for sure.

After admiring the robots, Microsoft led me into one of the quietest places on Earth: an anechoic chamber, which used to hold the world record for the world’s quietest place. The room is suspended and isolated from the room it’s inside of, which is also isolated away from the noise of Microsoft’s Surface buildings. Microsoft uses this room for audio testing, and it left me feeling like my ears were blocked up.

I stood inside the anechoic chamber to hear how audio plays on Microsoft’s range of Surface Laptops, which have no visible speakers. Instead, audio is pumped out through the keyboard, something that’s unusual for a laptop. The audio team has had to tweak the design of the keyboard on the new 13-inch Surface Laptop so it doesn’t rattle or resonate when it’s pushing sound out the tiny gaps between the keys and the chassis. Microsoft could have just added regular speakers to its Surface laptops, but the team decided to engineer something clever to make extra space for the row of function keys.

That kind of attention to detail really sums up everything about Microsoft’s approach to hardware design with Surface. Over the past decade Microsoft has pushed the boundaries of what to expect from PC design, particularly with products like the Surface Book or Surface Studio.

These latest Surface devices may have only shrunk in size, but Microsoft’s lab tour demonstrated that there’s still a lot of engineering required to make them smaller. I really hope Microsoft’s meticulous approach to developing this new pair of Surface devices is a sign that the company is still committed to pushing the boundaries of hardware innovation — something Surface has become known for — to bring us more interesting and category-defining designs in the future.

I’m always keen to hear from readers, so please drop a comment here, or you can reach me at notepad@theverge.com if you want to discuss anything else. If you’ve heard about any of Microsoft’s secret projects, you can reach me via email at notepad@theverge.com or speak to me confidentially on the Signal messaging app, where I’m tomwarren.01. I’m also tomwarren on Telegram, if you’d prefer to chat there.

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