On Apple’s choice of materials

Let’s talk about the use of Aluminium & Unibody

I still remember when Apple first introduced the Unibody concept as new and revolutionary. I remember thinking at the time how similar the Unibody shell looks to some enclosures used for auto parts:


Looks familiar, doesn’t it? So the manufacturing techniques existed before Apple introduced the Unibody design. The novelty was in the use of this material & technique to create a laptop shell.

The advantage in terms of manufacturing was a significant reduction in the number of parts used in the enclosure assembly. But how did this all come to be?

You see, other laptop manufacturers have used plastics for years. Most of those plastic shells are manufactured using injection molding techniques. You spend a lot of money making the molds, but once you have those molds you can produce millions of shells quickly and cheaply.

Apple used to do the same thing with its earlier laptops. One of the prettier plastic laptops Apple had ever produced (in my opinion) was the black PowerBook G3:


But when Apple introduced the first Intel based MacBook Pro, they went for Aluminium. The edges were plastic (and rounded, and we will talk more about that later), and the enclosure itself was made out of a plastic skeleton which held aluminium plates in place with screws. To assemble (and disassemble) the chassis took a significant amount of time & effort (and knowledge of which screw goes where).

Hence by moving to Unibody, Apple cut a significant amount of time & logistics in their their MacBook Pro manufacturing line, as well as in their labs while repairing laptops.

The advantages were clear:

  • Faster & Cheaper to produce
  • Less parts required
  • Less time spent on assembly
  • More durable chassis
  • Some advantages in heat dissipation touted

However, two major problems started plaguing MacBook users. One was fixed (kinda), the other is still a huge problem.

Problem 1: Soft metal will scratch, dent & bend

If it’s scratched, dented or bent, it’s there forever (unless you’re willing to go to the Apple store and pay for a replacement shell). Take a look at this image for example:


How many of you have dented their MacBook Unibodies? I’ve seen so many dented MacBooks I have lost count. In fact just search on Google Images and you’ll find plenty of photos showing dented MacBooks.

And if you’ve dented your MacBook once, you’ll probably be traumatized enough to buy one of those expensive protective plastic shells. So now you have an Aluminium shell, covered in plastic. And you won’t see Apple’s new recycling chief talk about that, because well, it’s not a part that Apple manufactures (but it does sell it at the Apple Store). On top of that, your laptop which was already pretty heavy before, is now significantly heavier (and thicker).

Problem 2: Sharp edges

And they used to be even sharper, with some web sites (such as LifeHacker) posting instructions on how to fix the problem. Apple sorta fixed this in their 2nd generation unibody. The edges are slightly more rounded.

However it’s now 2016, I have the latest MacBook Pro Retina. The edges are still sharp enough to cause discomfort during extended use. In fact I just lifted my wrists from the laptop, just to check, and I have a good 4~5 deep red lines on each wrist. They are painful, too. Apple cares more about the “clean & sharp look” of their laptop, than they care about your wrist pain.

Problem 3: Grip (or lack thereof)

If you have dry hands, you probably noticed how slippery your Aluminium laptop is. Which makes it so much easier to drop your laptop (which will dent/bend your laptop, throwing us back to problem #1).

However, this problem is not exclusive to the MacBook. As many of you have already discovered, the iPhone 6 series suffer from the very same issue, and worse. Unless you have a protective cover for your phone, you’ll find it’s extremely slippery and most iPhone 6’s that are used by their brave owners without a cover, have dropped so many times they are all dented, scratched and bent. In fact, the first generation of iPhone 6’s would bend in people’s back pockets. The problem was so widespread the media called it “Bendgate” (see CNN article on the subject).

Problem 4: Oxidation / Corrosion

“Aluminum corrodes but it does not rust. Rust refers only to iron and steel corrosion. Aluminum is actually very prone to corrosion. However, aluminum corrosion is aluminum oxide, a very hard material that actually protects the aluminum from further corrosion.”

I personally experienced two issues with corrosion. The first (and weirdest) manifested itself when I started wearing my wedding band. Something to do with the gold band touching the aluminium surface, coupled with me being grounded to the floor (via my feet) would sometimes create a tiny spark between the wedding band and the laptop. After a couple of months, the aluminium surface in that area where the wedding band touches suddenly had tons of black dots that were impossible to clean. Touching them revealed they were actually holes!

The second issue with corrosion happened with my Magic Mouse. The aluminium surfaces that came in contact with my thumb, ring finger and pinky, became completely corroded and full of holes. In a warm and humid environment, your hands might sweat and excrete various salts/minerals which interact with the aluminium.

Conclusion: Using metal for a portable product is NOT a good idea. Apple, if you’re reading this, please stop doing it. How about you switch to Carbon Fiber? It’s light, strong, and will not bend or dent. And for the price of this laptop, I’m sure you can afford to use this premium material. None of the problems above would happen if the laptops were made of either plastic, or carbon fiber.


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