When your average consumer watches any of Apple’s “how it’s made” videos, they likely have no idea what they’re seeing. But even first-year ID students, when shown a cutting head pivoting precisely around material, understand that this machine is not controlled by a guy named Joe turning a bunch of handcranks. We all know a 5-axis CNC mill when we see one.
Greg Koenig knows a lot more than that. The experienced industrial designer behind the Atomic Delights blog, Koenig watched the three Apple Watch manufacturing videos with an expert eye and a brain full of production methods, then detailed what we’re actually seeing, using his manufacturing expertise to fill in the blanks. In writing it all up, he reveals why no one is likely to catch up to Apple’s manufacturing prowess.
Here’s the video for the gold “Edition” model and some of Koenig’s explanations:
In the above shot [of the Gold watch], blanks are placed in an immersion ultrasonic tester. What Apple is looking for is the presence of voids or density variances within the structure of the blank that, under stress, could lead to part failure or surface defects as material is removed in further machining processes. This level of inspection is, to put it mildly, fastidious beyond where most other companies would go (save Rolex). Immersion ultrasonic inspection is typically reserved for highly stressed medical implants and rotating components inside of aircraft engines; not only does this step take time, it also is typically performed by custom built machines of tremendous expense.
Koenig covers nearly ten other processes for the Gold version alone before turning his attention to the stainless steel variant:
We see a few shots of the case in a 5 Axis milling setup with custom work holding, milling out the internal features at odd angles. In this shot, our part is flipped yet again and is being presented to the tool so the pocket for the Digital Crown and button can be milled. Machinists should note that Apple isn’t cutting the side button slot with a full-width cutter – the smaller end mill is slower, but produces a far better surface finish by avoiding chip thinning fluctuations.
Second to the CMM probing, Apple’s video team also has a serious thing for Apple’s automated polishing processes; understandable given that Apple has invested a significant amount of time and money climbing the polishing learning curve. One of the challenges of polishing is that Apple wants to keep crisp edges crisp, and buffing wheels tend to reach into sharp edges. Not only does this munge up and soften the edge in an undesirable way, it also rips the soft buffing wheel to shreds. Looking at this shot, we see Apple has custom molded gray polymer plugs for the lug channels, the strap release button slots and (unseen) the digital crown and side button. This allows the polishing process to have complete access to the case surfaces, without interrupting the desirable crisp edges.
Lastly he looks at the version made in aluminum, a material Koenig has more than a little experience with. “Though I design aluminum parts,” he writes, “I long ago gave up even attempting to craft them to Apple’s finishing standards.”
Another process Apple leads the world at is laser machining. We’ll see it twice in the Aluminum video, but the above picture is extraordinarily impressive. Machining tends to leave a little lip on the edge of metal, known as a burr. Often just 0.05mm thick, burrs are razor sharp and are the bane of a machinists existence. They can be milled off in the machine using very tiny tools, or removed by hand, or knocked down in tumbling, sanding or other processes – all of which present tradeoffs.
Apple is doing something utterly unique in this 5 seconds of video – they are using a laser to clean up any burrs or finishing defects from machining. You can see the laser quickly outline the lip of an inside pocket, and come in for a more intense second pass on the floor of that pocket. I would consider this (quite long) blog post a success if the engineer or designer who thought that trick up reads this and knows that this is an astonishingly brilliant trick they cooked up. Bravo!
What we’ve excerpted here is only a fraction of what Koenig’s done; we highly recommend any production method geeks read his entire piece. His summation even echoes the oft-told craftsperson’s principle imparted to Steve Jobs by his father, about the importance of finishing the back of a cabinet, even though it would be out of sight: “Nobody will see or feel the inside pocket for the microphone on the Sport,” Koenig explains, “yet it has been laser finished to perfection.”
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