Apple’s latest iPhones include designs radically different from last year’s. The iPhone 17 Pro and Pro Max surprised many because they switched from the titanium on the 16 Pro to aluminum. And the iPhone Air used titanium. What’s behind these changes and why are they so crucial? Here’s why the new phones look like they do.
Apple iPhone 17 Pro — an inside look
Apple
I talked to Rich Dinh, Apple’s Head of iPhone Product Design and Will True on the iPhone Product Marketing team for a deep dive into why the new phones look and feel like they do.
“We have a history at Apple of elevating design and innovation across all of our products, but particularly on iPhone,” True explains. “This year, we pushed our design and innovation boundaries even further with our new phones, with our best and most innovative lineup we’ve ever had.”
True is referring to upgrades like ProMotion finally coming to the regular iPhone, but also design changes such as the aluminum iPhone 17 Pro with vapor cooling chamber, and the technical achievements that led to the iPhone Air, which he calls an “entirely new category of iPhone.”
“Each model has been thoughtfully designed with specific goals in mind, and then we pick the materials for that, and we use advanced engineering techniques to achieve those goals. That enables these incredible new designs, the performance, and the capabilities that they offer to customers as well,” True says. The goal for the iPhone 17 Pro and 17 Pro Max was “to create the ultimate pro iPhone, and to raise that bar significantly farther than we’ve ever done before.”
This year’s Pro models could not be described as an iterative change. Is this why? “We really wanted to start fresh and come at it from the perspective of delivering incredible performance,” True says. Intriguingly, he says this meant a redesign “from the inside out.”
Dinh says that they “started by bringing the right materials to that design with aerospace grade 7,000 series aluminum. This is a high-strength material, an Apple-designed aluminum alloy, that we selected because of its light weight, its high thermal connectivity, and its incredible durability.”
Once the material was chosen, it turns out the process of production affects the properties of the result. “We started by extruding the material, heating it, and then forging it into the shape and geometry of that new unibody design,” Dinh says. “By forging that unibody, instead of milling it from a large block, and then welding it or joining it, we really improve the strength and the consistency, and massively reduce the amount of aluminum that we need to use. And the reason you don’t hear about this a lot is that while forging aluminum into these shapes is not easy, forging high strength aluminum is even harder. And it requires super-careful control of every variable in the process, including temperature down to the single digit degree that the aluminum’s heated to and even individual seconds that we’re heating, just so we can create the exact performance characteristics that we’re looking for in this aluminum.”
The aluminum is essential to the performance, then, and because the Apple A19 Pro chip is the most powerful Apple has made for an iPhone, the design also needs to deal with the heat that power generates. The A19 Pro has a six-core GPU, with neural accelerators in each core, designed to cope with AI and local LLM tasks and enable hardware-accelerated ray tracing. “To maximize the performance, we needed to create a new thermal architecture as well,” Dinh says. Material design and silicon design work hand in hand leading to Apple embedding a vapor chamber in the iPhone with an enclosure made of 100% recycled copper. It’s positioned in a place that is good for uniform heat distribution.
Vapor Chamber in the iPhone 17 Pro
Apple
“Inside the vapor chamber is a single droplet of de-ionized water that’s vaporized by the heat that’s generated in A19 Pro,” Dinh reveals. “That vapor transports itself away from the heat to the cooler regions of the product, where it rejects the heat, and then condenses back into water. And then we have a wick in the system that pulls it back to the hot area, and that cycle continues through capillary action. Now, the vapor chamber in our product is laser-welded into the aluminum chassis, at strategic locations, and the metallic bonds that you get from laser welding versus glue or tapes, is really effective at transferring heat into the system versus what you commonly see in other vapor chambers.”
This architecture,” Dinh goes on, “combined with the aluminum chassis that’s connected to strategic points in the system, allows us to control and direct the heat where we want. We can also use small air gaps to limit where we don’t want heat to go. That strategic placement also allows us to utilize graphite heat spreaders to help spread the heat through the internal structure, and into that inner body enclosure, and then out into the environment. around the phone. This is where the use of aluminum is critical, it’s not just a vapor chamber, it’s the full system.”
This partly explains the move from titanium to aluminum for the iPhone 17 Pro chassis — aluminum is 20x more thermally conductive than titanium.
“What’s great for iPhone users,” True adds, “is that all of those systems work together, and combine to make for 40% better sustained performance for 17 Pro and 17 Pro Max than last year’s Pro Models, which were already incredibly performant. That makes a huge difference for intensive tasks that you’re doing for a long time, whether that’s playing a game with high frame rates and using hardware-accelerated ray tracing, but also for other types, like loading onboard LLMs and using those locally, and any of these things where you’re going to be using high power to the CPU and GPU for a sustained period of time.”
Apple iPhone Air’s back glass
Apple
Titanium, meanwhile, was crucial for the other iPhone with radically different design this year: the iPhone Air.
“With iPhone Air, we set out to create something completely new. It’s an iPhone that feels like you’re holding a little piece of the future. The design is thin and light, but we wanted to also deliver all-day battery life,” True says, “and we needed a series of new technologies and innovations to achieve that.”
“An essential part of that thin design is the grade 5 titanium,” Dinh explains. “The titanium strength-to-weight ratio made it perfect for the frame, giving strength and durability that defies expectations on what a thin design is capable of doing. In fact, Air is more durable than any previous iPhone. The titanium enables us to exceed our stringent bend strength requirements, in a phone 5.6 millimeters thin. And the iPhone Air utilizes 80% recycled titanium, which is the highest ever in any iPhone.”
“One of the critical innovations that we brought was the manufacturing. The USB-C port is made from 3D-printed titanium directly onto the bottom housing for that port. And even the titanium powder that we use is 100% recycled, improving in the process, plus the use of the powder improves the material utilization by 33%. So we’re bringing a lot of new manufacturing techniques and ideas to this platform. And the camera plateau is another great example. It’s milled from the inside and the outside, creating that volume that allows us to utilize space for critical components like the A19 Pro processor, the camera systems and more. It creates a lot more room for the battery. To maximize capacity for the battery, we also took the step of making this the first iPhone to use eSIM only worldwide.”
The battery itself, I’m told was constructed out of “our most advanced stainless steel enclosure, which allows us even higher energy density than the common designs that you’ve seen. This means we’re able to deliver the same 27 hours of video playback we had with iPhone 17 Pro.”
Nothing, it seems, is decided in isolation: performance and design are interwoven at every level.
