Apple is the world's foremost manufacturer of goods. At one time, this statement had to be caged and qualified with modifiers such as "consumer goods" or "electronic goods," but last quarter, Apple shipped a Boeing 787's weight's worth of iPhones every 24 hours.
When we add the rest of the product line to the mix, it becomes clear that Apple's supply chain is one of the largest-scale production organizations in the world.
While Boeing is happy to provide tours of their facility in Everett, Washington, Apple continues to operate with Willy Wonka levels of secrecy. In the manufacturing world, we hear rumors of entire German CNC mill factories being built to supply Apple exclusively, or even occasionally hear that one of our suppliers' process experts has been "disappeared" to move to Cupertino or Shenzhen. While we all are massively impressed with the scale of Apple's operations, there is constant intrigue as to exactly how they pull it all off with the level of fit, finish and precision obvious to anyone who has examined their hardware. This walkthrough is a detailed narration of what we see in Apple's
Watch craftsmanship videos. Of course, we get to see only a mere fraction of the process; I've tried to provide plausible explanations for the likely steps taking place between the processes shown on film, but these are assumptions and are included only to provide a more satisfying and complete narration. Gold Gold has always been the wrong metal to make a watch out of; its low yield strength and softness is incompatible with the tremendous amount of abuse an object worn on the wrist receives on a day-to-day basis. Driven by a history of desire going back millennia, alchemists and metallurgists have alloyed pure gold with nearly every combination of metals on the periodic table in order to overcome these limitations. The standards for 18-karat gold allow for a tremendous amount of leeway in producing innovative alloys (which may be comprised of anything, as long as the final product contains 75%-79.99% pure gold by weight), and major producers of gold goods have used that flexibility to each create proprietary formulations in an attempt to gain competitive advantage. Rolex built an in-house foundry at their Plan-les-Ouates complex in Geneva to produce all of their precious metals. Hublot has trumpeted their composite ceramic "Magic Gold" as being significantly more durable than anything else available. Recently, Apple patents were uncovered detailing a metal matrix composite process to produce 18-karat standard compliance gold with a significant weight reduction and durability increase. apple1 IMAGE: APPLE For the Watch Edition, however, Apple appears to have eschewed any revolutionary alchemy and instead applied an innovative work
hardening process to create gold that is (claimed to be) significantly harder than the typical 18-karat used by other watchmakers. The first portion of Apple's "Gold" video is carried by the beautiful alloying process and Jony Ive's meditative voice; at the 1:15 mark, however, things begin to get interesting. Work hardening is one of those counterintuitive industrial processes where we take an undesirable aspect of a material and judo it into a significant improvement. As the gold is cast into ingots, the crystalline lattice structure of the alloy is nearly perfectly aligned. What Apple is about to do is introduce — in a highly controlled and precise manner — defects in that lattice (known in the art as "dislocations"). The effect is to harden the material by giving future impact events or stresses a limited number of spots on the lattice to start (technical term: nucleate), and if they do start, very little room to propagate. You can experiment with this yourself using a metal paperclip — start bending the paperclip back and forth and you'll notice it gets ever so slightly more difficult to bend as you repeat the process. Eventually, you will create so many dislocations in the metal that the part will fracture into two pieces, but for a short period, you will have work hardened that section to a point where some potentially desirable material changes would have taken place. Add a tremendous
amount of precision, use equipment capable of applying thousands of tonnes of force, replace the paperclip with a $50,000 ingot of gold alloy, and you're working at Apple. apple2 IMAGE: APPLE The process Apple shows begins with the raw cast ingots getting machined with an index cutter face mill to a very precise thickness. Casting is a process that doesn't offer the level of precision Apple needs for the next step and this machining allows them to control the dimensions of the ingot to within 0.01mm. This level of precision is necessary because any variations in the surface of the ingot would create variations in the hardness across the final part.
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