Re: gEDA-user: Outsourcing PCB layout

[msokolov@xxxxxxxxxxxxxxx (Michael Sokolov)]

Kai-Martin Knaak <kmk@xxxxxxxxxxxxxxx> wrote:

> A bill of material (BOM) woud help to estimate the necessary effort. The 
> BOM should include the package of the parts, especially of the connectors 
> and special ICs.

http://ifctfvax.Harhan.ORG/OpenSDSL/OSDCU/OSDCU-AA.bom
http://ifctfvax.Harhan.ORG/OpenSDSL/OSDCU/shortbom.txt

> So it can be seen whether or not all footprints are 
> available in the existing pcb libs. 

I have already drawn all the necessary footprints in the PCB format.  I
have provide them either in the form of a file-per-element tarball (each
file inside named after the refdes) or in the form of a .pcb file like
you would get from an initial gsch2pcb run.

> Maximum PCB size matters. An otherwise unspectacular layout task can get 
> really nasty if the maximum allowed size is below a certain threshold. 
> Again, a BOM would help to estimate.

Because it's a totally non-commercial hobby project, terms like "maximum
allowed" are not applicable.  The size I have specified (130x165 mm) is
only a suggestion - I had come up with it by measuring the size of an
existing DSL modem board whose circuit complexity appears similar to
mine.  But again, it's only a suggestion - if a different (larger) PCB
size would result in a significantly lower layout labor bill, go for it!

> If cost is a factor, why not aim for four layers but slightly larger size?

The only cost that is a factor is the layout labor cost, and I thought
that having more layers makes the layour labor easier.  The cost of
physically making the PCB is not a factor - I have checked pcbexpress.com
and their price for a 6-layer board of the size I have in mind is
perfectly affordable, which is all that matters.

Again because the project is non-commercial, mass production is not a
consideration.

MS


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