The thing is, you need to understand how the production lifecycle of a product works. I would imagine that all electronics manufacturers follow a similar process to the automotive company I work for.
With modern manufacturing techniques, it's possible (and desirable) to get out of the prototyping stage as early in the project as possible. Just because you're using production tooling, doesn't mean it's a saleable component though. The reasons for doing this are:
- Modern CAD allows very realistic simualtion of compents and circuitry elimintating traditional early component testing of initial ideas.
- Prototyping components is incredibly expensive. Something like a prototype phone chasssis could be anything from 10-100 times more expensive than a production part. This adds up when you need several hundred prototypes.
- Production tooling costs are less than they used to be.
- Experience and simulation reduces the number of design changes and hence reduces the likelyhood of expensive tool modifications.
- Off tool parts give more reliable results during testing.
Where I work, we make products that use off tool (ie production) components as far away as 1-2 years before volume production. They are not salable though.
I suspect Apples design cycle will be something like:
1. Hacked about current generation phones to validate software.
2. First build up. I suspect the architecture is laid out early on, so chassis may be off tool, but boards might be prototype. Will lack certain things like new screen/cameras that don't help validate robustness of new design
3. First fully working and representative prototypes. Likely brought in components that are representative from suppliers such as screen, cameras and some of the boards. They'll still want to tune stuff at this point though, so Apple designed components like the main board my still be prototyped. iPad was likely the lead project for the A4, so that'll be off tool. Certain key areas will still need tuning. This will likely be board mounting and battery which can all need intensive testing to validate.
4. Final validation prototypes (maybe 2-3 months max before launch). This will run everything off tool minus perhaps a few minor bits of trim. They are probably salable, but with electronics where unit value is incredibly low, they probably won't reach the public.
At this point, some final mods to the production tools will be made. Any texturing to plastic/metal parts will be added (chemical process which etches surface of the tool) and final production orders will be placed. It's now up to the suppliers to try and meet the orders which isn't always possible. Late changes will delay orders as will discussions over final costs. Once the order is placed, it'll then be 6 weeks or so to initial samples which must be inspected.
Everything will be run as tight as possible. I suspect production ramp up started perhaps 3-4 weeks ago max. That said, it takes a few weeks for them to get up to full speed.
Apple will be trying as hard as they can to deliver as many units as possible. It's in their advantage. The longer the delay, the more people they miss who are only casually interested. Whilst us lot are all desperate for it, and will wait, I expect 90% of iPhone sales during its life cycle is an impulse buy. Purchase will depend on when a users contract comes up for renewal and availability. Right now, if Joe Bloggs (or Jon Doe for you over the pond) is looking for a new phone, given the choice between an HTC Hero now or a 3 week wait for an iPhone 4, they'll choose the HTC because on paper it looks as good, and they can get one tomorrow.
