[gta02-core] Use for hole left by GPS connector - shields

Werner Almesberger werner at openmoko.org
Tue Jun 30 08:24:38 CEST 2009

Rask Ingemann Lambertsen wrote:
> But creating the support for bending the can is the "interesting" part of
> it.

For small numbers, maybe you could just make a block of aluminium
to support the edges, fold with some other piece of metal, and then
finish manually ?

> 1) Mass production of a few thousand cans. OM found something that worked.
> Do we know how much it cost? From the PCB photos[1][2] it looks like the
> shape of the cans was not changed from the GTA01 to the GTA02 in spite of
> substantial PCB changes, suggesting tooling costs were an issue.

Or maybe just nobody was interested in changing that. All of the
cans are reasonably full in GTA02, so there wouldn't be much to gain
by resizing them. gta02-core should have a bit more room, though.

>    Perhaps I should pay a visit to <URL:http://www.etch.dk/>.

looks about as complex as anything we could possibly want :)

>    On the photos, it looks like they've etched partially into the material
> to create a weak line to aid in bending the cans.

Yeah, I wonder how they did this. Would stamping also be a
possibility ?

> They're using 0.381 mm
> brass, which is quite thick. I was thinking along the lines of 0.15 mm MA3M
> stainless steel,

Openmoko use some 0.2 mm material. Not sure what it is.

>    How are the shields soldered to the PCB at the factory?

I think the place the components first, then the shields, and then
it's off into the oven.

>    Maybe the can was just made as large as possible to not limit the GPS
> part design too much. If the gta02-core GPS part will fit in a rectangular
> can, then there's nothing to stop us from using a rectangular can, is there?

Yup, that's a possibility. With the large curves of the case, you'd
lose a fairly large part of the can surface, though. Particularly
the GPS can is almost entirely on a curve :-(

- Werner

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