In the next Xmas quarter, Apple will need to produce 80 million iPhones —that’s about the number Apple disclosed before it decided to no longer give out units data. Given 8 million seconds in a quarter (90 days * 24hrs * 60mins * 60 seconds = 7,776,000 seconds), this yields a nicely rounded production requirement of 10 iPhones per second — 24 hours a day!

Origin: Jean-Louis Gassée – $12B TSMC US Plant: What Problem Does It Solve?

How many production lines are needed to create that many devices? Let’s say the assembly, test, and pack process for one iPhone takes 10 minutes (600 seconds). This means a single production pipe can output 1/600th of an iPhone per second. If you trust my math, producing 10 iPhones per second would require 6000 assembly/test/pack pipes working in parallel.

I’m probably wrong, but how wrong? Can the whole process take 1 second? This would require only 10 production lines working in parallel. No, that’s not realistic. One minute? Doubtful. That would still demand 600 production lines in parallel.

This little simulation, imprecise as it certainly is, gives us a workable idea of the immensity, to say nothing of the seasonality, of the iPhone manufacturing process. In particular, it involves the size and type of manpower flows that only a company such as Hon Hai Precision (a.k.a. Foxconn) knows how to provide. Foxconn’s knowledge, ability to draw from a massive manpower pool, and the will to impose tough working conditions while also dealing with a seasonal ebb and flow are nowhere to be found or accepted in the US.

This leads one to say that the current style of iPhone manufacturing isn’t possible in the US.