Nils Faerber <nils.faer...@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 with vhdl. > > 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 > irrelevant. > > 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... > > Cheers > nils faerber -- Joakim Verona _______________________________________________ hardware mailing list hardware@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/hardware