I've seen article about World's First 3D Printed Bike.
What kind of printer is required to do that, briefly how long it takes and how much does it cost? Is this even achievable at home? Doesn't need to be that specific one.
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You will need a laser sintering or lasercusing printer, which will not be something you can buy for home use. They are horribly expensive.
You could always print this in PLA or ABS and cast it in aluminium. Then you have to find a safe method to test the result, because casting is not quite as simple as it looks and the bike could be seriously dangerous.