New Life in Openmoko Phones
joakim at verona.se
joakim at verona.se
Tue May 19 20:13:48 CEST 2009
Nils Faerber <nils.faerber at kernelconcepts.de> writes:
> He ;)
> Many of the parts in the GTA02 cannot be reasonably placed by hand.
> There are almost a dozen (or more?) BGA chips which are extremely hard
> to handle (you do not see if the balls match the pads). Then there are
> almost microscopic parts like resistors and capacitors - which pitch?
> 0402 at least if not even 0201 or smaller. So populating the board is
> almost impossible by hand without highly qualified tools (and no, a
> tweezer and a stereo-microscope will not suffice).
> But the problem you will encounter beforehand is printing the solder
> paste. Stencil printing such high density with even and correct paste
> distribution is not exactly easy even if you have proper stencil
> printers. Adjusting them, having the right paste to print etc. is high
> art of SMT manufacturing. And finally you need a really proper nitrogen
> flooded full convection reflow oven for good quality soldering of such
> delicate parts (different heat absorption of parts, proper heat
> profiles, good energy distribution, etc.).
Well this just goes to show that the last time I did serious electronics
we prototyped with wire wrap guns and stuff :) At least we made vlsi:s
> So what you really need is a modern manufacturing line, with auto-placer
> for almost all parts. I do not know how many different parts there are
> on the GTA02, probably 100, or even more? This means very high initial
> effort for setting up the machine to pupulate a board. If you then run 1
> or 10 or 100 does not make much difference for the machine cost anymore
> (you just need more parts). The setup effort is the thing that makes
> prototypes or small series such expensive. I just visited another
> electronics maker here in Germany and they have a placement machine
> which can set up to 85000 parts per hour. Compared to something like a
> day for setting up the machine, the time placing the parts is almost
> The smaller the parts have got in the past the more difficult it has
> become for hobbyists to catch up with technology. It will not take very
> long until home-grown PCBs will be almost impossible to do because all
> the interesting chips come as bare-die only (just the silicon, no case
> or pins).
> So what is needed is the real commitment by some professional hardware
> manufacturer to put the new design on one of his lines and care for the
> prototyping and small initial a-series. After the design has proven to
> work a small first production run should be easier to setup since you
> can then give proove that it will work and persuade potential customers
> to pay up-front for the device - or at least a part up-front. That would
> enable buying the parts and paying for setting up the production. I
> think the Open Pandora people did it quite similarly, i.e. they sold
> devices and had them made after sales. If your customers trust you
> enough this can work.
> So in the end hardware making is more a matter of money than motivation
> or man power, pitily...
> nils faerber
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