How are Macs manufactured/quality controlled?

satchmo

For instance, how is a new product is such as a Powerbook, manufactured?



At what point does the QC inspection take place? I'm guessing any problems caught pertaining to fit and finish, latches, screen quality etc...are made from off production line units and not one off hand made prototypes.

If so, isn't this pretty late into the process to fix. Does that mean re-tooling and if so, isn't that mega bucks? Of course, design is computerized and roboticized, but I'm guessing there's still room for error.

BTW, this is not a slag on Apple, but really a general question on the process.

mmmpie

Im no engineer, but my understanding is as follows:



A short run of machines would be manufactured using cnc milling and other techniques to check for gratuitous design faults. These machines would be the ones used for initial destructive testing to establish limits. If there are any issues here then the design will be fixed ( hopefully ) and the process repeated untill the design is working nicely.



Im not sure how often this cycle is run before the design is finalised. But when it is dies will be manufactured for mass production. The problem here is that the die may not match the original design very well, and due to cost there is pressure not to fix it ( untill it has at least paid for itself ). On top of that, dies wear out, and that rate of wear may be fast enough that replacing the die is uneconomic, and therefore not done. Small runs ( of which Apple may count ) are produced by milling. Milling doesnt produce 'identical' copies. All of this adds up to variance. If the original design specs failed to allow for the total variance present in an individual machine coming of the line then aspects of the design may fail. I think examples of this are failures of various Apple laptops, hinges, screens cracking, etc.



However, some design decisions are simply bad. Audio sockets are regularly under specced, requiring repair. I dont like the quality of fit between my iBook battery and case, etc etc.



The biggest issue I see is that Apple are now out sourcing most ( if not all ) machine production to Taiwan. It is without a doubt the responsiblity of the Taiwanese manufacturers to determine when a die needs to be replaced. If they push the limits then they will be producing sub par machines. In the case of areas where a failure is only going to occur after a period of time then those machines will pass Apples QA process.



It all comes down to cost. QA costs money, so there is pressure to skimp on it, and suffer the consequences later.

danmacman

Well if its anything like an auto industry assembly model, which I have worked and been a part of, the parts are assembled down the line, and at the end of the line there is a QA station. Then parts are shipped to another part of the plant where they go through QA again. If parts need work, they are broken down and sent back to assembly. I am sure things are somewhat different for computers, but the premise is probably similar.