There are many issues that manufacturers have to dodge when designing a very thin laptop. The electronics have to be organized differently. The material cannot twist if the device is opened improperly, because if it does it might wreck the screen. Cooling becomes a huge issue, because fans take up a bunch of space but they’re also very, very necessary, and flatter devices are competing for less air space inside, not less.
My least favorite issue, though, is considerations of a device’s weight. Why try to make things lighter and sacrifice strength for it if the device is already paper thin and prone to blowing away in the wind?
Aluminum
Most of the issue is already solved by the time you get to it – less material means less weight anyway, unless you’re working with some exotic, non-Euclidean material the rest of us aren’t privy to yet. However, manufacturers often believe in perfection, and the question they ask themselves is ‘how close can we get to a mathematically ideal device before the clumsier part of our client base destroys them just by looking at them?’ Not every device is destined for a desk, and not every device is going to be set down once and only picked up for cleaning.
This is why straight aluminum is often not considered. Aluminum, while lightweight and flexible, is too flexible at the thickness a computer’s shell needs to be. Think back to the iPhone 6, and #BendGate – if they tried to use aluminum, they’d lose the benefit of the aluminum because it would need to be thick enough not to bend under its own weight, or the weight of the user’s hands. Even now, iPhones use alloys instead of the pure material because it’s a better fit.
Magnesium and carbon alloys are heavier, but they’re also less flexible, meaning that opening the screen from one side doesn’t put so much pressure on the delicate electronics inside the upper half of the device. This is the ideal! But what if I don’t want the ideal? What if I want a laptop that could harm me severely if I dropped it on my foot? What do I do then? And, is it possible to do this purely with different materials and not rearranging the design?
The first laptops on the market were super heavy – I want a modern laptop that’s thin enough to fit in a backpack, even if it tears the handles off.
Critical, Unchangeable Components
The most literal interpretation of this would to be replace everything with something like plutonium, which is technically a metal. But, radioactivity interferes pretty badly with electronics, so all of the heaviest elements are out right off the bat. If this device is going to work, it’s got to meet certain specs.
The battery is almost always going to contain lithium. The optimal weight-to-thinness ratio is already determined, this is a hard and fast rule for laptop computers until the next big breakthrough a la Tesla and the car market. The casing for this battery, too, represents the ideal strength and lack of flexibility AND permeability necessary for laptops, so it can’t be made heavier either. Fans could be heavier, made with thicker blades and heavier material – but increasing the weight of the fans would mean that powering them takes more energy from the battery, cutting it’s life, so fans are an suboptimal place to add weight back in to the device.
The same goes for the plastics in the device, mostly within the screen and keys. Changing plastic at the desired thickness is usually not going to result in a positive weight change, but will result in a worse experience for the user. The older glass and plastics used in touch screens were heavier, but they were less responsive to touch and prone to false positives and wear-out. Cold metal keys are slightly less pleasant to touch than the non-conductive plastic ones used everywhere else, and metal circuit boards present a unique set of issues solved a long time ago by the PCBs (printed-circuit boards) used today for almost everything. Those can’t be heavier or swapped out for a different material without requiring major redesign.
Additionally, there is some empty space inside most laptops – that space aids air flow and cooling, so stuff can’t just be thrown in there without disrupting user experience elsewhere. Besides the weight thing.
Replacements…?
However, looking closer at the contacts beneath the keys and behind the screen, there is something slightly heavier we could use: silver. Silver surprisingly conducts just a smidge better than copper does. 1 cm^3 of silver weights 10 grams, where 1 cm^3 of copper weighs about 9. Not a huge change, but you might notice it. We don’t use silver in devices because of the price, not because of the additional weight, although that would eventually add up in larger, heavier-duty devices.
As a side note, gold conducts significantly worse than copper does. Not enough to make it not worth using if it’s the only HDMI cable you can find in the store, but enough that a straight copper HDMI cord, even if it costs more, is probably going to give you better performance.
Onto the rest of the computer!
Steel is common because of how widely available it is, but the steel alloys commonly found in devices like laptops are usually only found in the structural parts of the device, not the shell, because steel is heavier than aluminum alloy for the same volume of material. You could replace everything with steel – but there are actually heavier options. The outside case is not responsible for conducting electricity and only partially responsible for dispelling heat. Carbon fiber shells are becoming more popular because manufacturers have realized this, but they could also replace the entire outside shell with platinum. Or tungsten.
Tungsten in particular makes a better choice because it’s extraordinarily hard and won’t snap the stuff inside the computer when you go to open it. You’ve probably heard the term tungsten-carbide – the alloy contains equal parts tungsten and carbon, and the end result (while lighter than straight tungsten) is one of the toughest alloys available on the market.
Consumer sites say the average 15 in laptop is about 5 lbs. Assuming 50% of this is internals and the screen, 2.5 lbs of aluminum alloy could be replaced by an equivalent weight of 17 lbs of straight tungsten metal. That’s what I’m talking about!
Heavier In Use
The Macbook’s delicate, flimsy butterfly switches provided an uncomfortable typing experience for some – a couple of reviewers likened it to slapping their hands onto straight vinyl over and over as they typed. The keyboard didn’t physically have the space to respond the way most other keyboards did. However, other laptop brands with ordinary scissor switches sometimes also have this issue, because they’re so thin that the ordinary scissor switch mechanism doesn’t provide a satisfying amount of resistance, either too much or too little. Altering key height allows you to also alter resistance, but if you’re really desperate for a keyboard that feels meatier than the one you’ve got, a mechanical keyboard may be your new best friend.
The same goes for the mouse, and the trackpad – you can do things to these items that makes them feel heavier in use. You can also just literally add weight to things like the mouse – the electronics inside are very small, the mouse is just the size it is because it makes it easier for larger human hands to use.
These devices can be heavier. Who does that benefit? I don’t know. But they can be.
Sources: https://www.tomsguide.com/us/gadget-materials-guide,news-22743.html
https://www.techwalla.com/articles/what-elements-are-used-in-laptops
https://www.bluesea.com/resources/108/Electrical_Conductivity_of_Materials