Re: gEDA-user: single-sided boards

[Steven Michalske <smichalske@xxxxxxxxx>]

On Feb 28, 2009, at 11:21 AM, Stuart Brorson wrote:

> Hi --
>
>> How often does the need for single-sided boards arise?
>
> The question about single-sided boards is interesting, but the
> answer depends upon how you intend to fabricate your boards.
>
> If you're sending the boards to a PCB manufacturer, then the raw
> material they use is fiberglass clad with copper on both sides.  In
> this case, it's senseless to ask for a single-sided board to save
> costs -- they start with a double-sided board in any case.

To be fair,  this is true when making few boards.

AKA less than a LOT

Your PCB manufacture would order single sided stock if you were making  
say 10,000 boards plus.
Or if you were dealing with a manufacture that dealt a lot with single  
sided boards.

TV manufactures and boom box makers use these tricks, but they also do  
things like use FR2 http://en.wikipedia.org/wiki/FR-2

The quick turn PCB houses online,  usually don't run single sided for  
small jobs,  as they panelize your board with others, that are most  
likely double sided.

>
>
> If you're making the PCBs at home, starting with single-sided
> fiberglass from e.g. Radio Shack, then it's totally sensible to make
> single sided boards.  In this case, just throw away the back side
> Gerber file.
>
>> this kind of
>> cosmetics with gerber files is an additional error-prone manual step.
>> Has it been considered to make this an option that is supported by  
>> pcb?
>
> I agree that it tends to trip up newbies.  However, there's one Gerber
> file per (metal) layer, so you can always discard the back side file
> without any problems.
>
> More to the point:  the Gerber, and the related drill file
> formats are pretty stupid.  They don't carry any top-level
> information about your design.  A particular Gerber file knows only
> about its own layer, and knows nothing about any other layer.  The
> Gerber files have no concept of "stack-up" (i.e. what order the layers
> are supposed to be stacked in).  The drill file only contains
> information about what drill diameters to use, and where to put the
> holes.  The remaining information, like stack-up, plated
> vs. non-plated holes, how thick your copper layer should be, how thick
> your FR-4 should be, desired manufacturing tolerances, etc., are all
> told to your PCB manufacturer using "fab  notes" (i.e. a
> human-readable text file) and a "fab drawing" (a drawing of the board,
> stack-up, and other graphical info).
>
> Finally, one of the projects slated for work under the Linux Fund's
> PCB project is to update PCB's handling of layers.  Things like the
> ability to easily deal with single sided boards from inside of PCB
> are part of the work to be funded by the Linux Fund. I'll just remind
> everybody that they can make this work happen sooner by making a
> donation!
>
> http://www.linuxfund.org/projects/pcb/

Thanks for the reminder, I just chipped in some.
>
>
> HTH,
>
> Stuart
>
>
> _______________________________________________
> geda-user mailing list
> geda-user@xxxxxxxxxxxxxx
> http://www.seul.org/cgi-bin/mailman/listinfo/geda-user



_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user