If you are an experienced person, you would not need to ask us here.
If you are unexperienced in this area which is really a "cut throat" area and subject to price fluctuations of quite a large sort, may I suggest that you find yourself an easier business to invest in......
Sorry to be so negative.....but very honest.
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"What others say about you reveals more about them, than it does you." Anon.
how much R&D have you done? apart from picking up a soldering iron and thinking "Well this is easy"
What are you going to do that is so different? what are the quantities? how are you going to compare manufacturing costs with China and their mostly disposable workforce?
You going to use P&P (Pick and Place) or hand loading (some Chinese companies do hand loading of <1mm chip components, P&P will only raise the manufacturing costs)
Have you thought about the selling price of the devices?
I can purchase here in Australia a SanDisk Micro SDHC 4GB for $40
are you going to be able to beat that?
and the packaging, are you going to be manufacturing that in house too?
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Qn, Whats the differance between a Snake and a Onion? Ans, No one cries when you chop up a Snake