[sdiy] Eagle analogue & digital groundplanes

[rsdio at audiobanshee.com]

For folks who are in the Seattle area and are interested in crazy technology, Metrix Create Space has a LPKF Protolaser S that will cut PCBs with 2 mil traces and 2 mil spacing. The boards look great, but it might be tricky to do a multilayer board. Even though they can handle 16 layers, I think it becomes more difficult as there are more steps. I haven't been by there to see recent boards, but I designed the first PCB that they built - destined for wearable computing. This was for a DARPA project, but the facility is non-military and non-NASA. They charge $12.50/minute for use of the machine, so it's accessible to just about anyone who can produce Gerber files.

So far, I've not wanted to go that extreme for the projects I'm working on. The LPKF is actually a bit expensive if you're not in a hurry or working really small. But it's great to see such technology with widespread access.

Brian


On Nov 29, 2015, at 11:17 PM, Sarah Thompson <plodger at gmail.com> wrote:
> It's not *that* hard to get that many components into the space -- it would have been easier if I could have used BGAs, but they are generally not preferred for space applications so I had to get a waiver for the FPGA. It basically means being REALLY careful about placement. If I could have used standard vias it would have been easier too, but 4 routing layers and a really fine pitch helps a lot. Looking at the board under a microscope (sorry, I can't post photos!), there's not really much sign of any variation in trace widths, even though the LVDS pairs are so fine that they look like a single trace usually to the naked eye. The board house actually could go even finer, believe it or not.
> 
> The main trick is that is *must* be assembled by a robot to stand any reasonable chance of working first time. We had the assembly house do flying probe tests after the board was populated to make sure it was kosher, but the boards were all 100% tested before assembly too.
> 
> I'm a bit spoiled by being based in Silicon Valley -- it does make finding that kind of crazy capability a lot easier.
> 
> Sarah
> 
> On Fri, Nov 27, 2015 at 1:52 AM, john slee <indigoid at oldcorollas.org> wrote:
>> On 27 November 2015 at 20:30, Roman Sowa <modular at go2.pl> wrote:
>>> Can't imagine 500 components on 2.5''sq. People call that alien technology, and who has access to real alien technology if not your employer...
>>> 
>> +1, I would love to see this. I'd make it my desktop background. Particularly if it was a nice white PCB!
>> 
>> John
>> 
>