kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxx>]

On 8/22/2017 8:05 AM, Bastian Neumannn wrote:
> Hi
> 
>> Ultimately is it useful to design a board, if you cannot make it?
> 
> Right now I can fabricate boards, I can not design. That is also not a
> good solution.
> 
> via constraints are tricky bussiness as they are very specific to the
> manufacturer.

I'm not opposed to this change.  However, there are two schools of
thought when it comes to board layout: strict layout constraints and no
layout constraints.  I tend to lean towards the latter but I've been
doing this for 30 years so I am painfully aware of the pitfalls of no
layout constraints and have a pretty good idea of what not to do.
Should we choose to loosen the layout constraints for blind/buried vias,
then we should be prepared for a serious tongue lashing the first time
someone violates their board vendor's manufacturing limitations and ends
up with a bunch of useless and likely expensive boards.  Maybe at some
point in the future we will have a complete constraint system that can
cover all possibilities but until then we have to walk that fine line
between power users and beginners.

> 
>> PS:
>> The current "tracks and vias editor" dialog is (for me) a not finished work:
>> It does not make any DRC test after editing, and this is *really annoying*.
> 
> This is what I am working on at the moment. To have a propper mask where
> one can input constraints for vias.
> 
> At the moment you can only define some layers. There is much more work
> to do. Like staggered/stacked µvias
> 
> Inline-Bild 2
> 
> Based on this dialog I plan on having more layer masks to only show
> layers described here.
> 
> Cheers
> 
> 2017-08-22 13:00 GMT+02:00 jp charras <jp.charras@xxxxxxxxxx
> <mailto:jp.charras@xxxxxxxxxx>>:
> 
>     Le 22/08/2017 à 12:10, Simon Küppers a écrit :
>     > I second this. Working in a Research Institute I can assure you, that very often there are circuit
>     > boards with "interesting" stackups and via configurations... These boards are not produced by
>     > quick-turn factories like eurocircuits but companies such as ILFA or Optiprint.
>     >
>     > It would be unwise to cut out those users from KiCad.
> 
>     I dont't remember I said we should restrict vias to eurocircuits
>     constraints.
> 
>     Moreover "very often there are circuit boards with "interesting"
>     stackups and via configurations"
>     lead me to think there are constraints, unless I missed something.
>     (if there are "via configurations", there are constraints)
> 
>     I don't think eurocircuits is at quick-turn factory (although I have
>     myself any experience about
>     blind/buried vias) but I think blind/buried vias can have
>     constraints, because I saw constraints in
>     board houses.
> 
>     Ultimately is it useful to design a board, if you cannot make it?
> 
>     In fact, Pcbnew is really lacking a board stackup editor, to define
>     not only the stackup layers, but
>     some other parameters (via parameters, copper thickness, dielectric
>     thickness and type, and a few
>     other parameters).
> 
>     This board stackup definition is needed not only for vias, but also
>     for impedance controlled boards.
> 
>     PS:
>     The current "tracks and vias editor" dialog is (for me) a not
>     finished work:
>     It does not make any DRC test after editing, and this is *really
>     annoying*.
> 
> 
>     >
>     >
>     > Am 2017-08-22 09:57, schrieb hauptmech:
>     >> On 22/08/17 18:25, jp charras wrote:
>     >>> Le 22/08/2017 à 05:55, hauptmech a écrit :
>     >>>> Manufacturing techniques vary between manufacturers and
>     continuously evolve. Why would kicad limit
>     >>>> itself to what eurocircuits can do? They have optimized their
>     process for quick turn prototyping
>     >>>> and
>     >>>> while they document their process nicely, they are probably not
>     a good reference for what can be
>     >>>> done.
>     >>>>
>     >>>> On 21/08/17 05:44, jp charras wrote:
>     >>>>> Before working on blind and buried vias dialog, please have a
>     look at:
>     >>>>> https://www.eurocircuits.com/blog/Blind-and-buried-vias
>     <https://www.eurocircuits.com/blog/Blind-and-buried-vias>
>     >>> Currently there is no control in Kicad.
>     >>>
>     >>> Sure, but it looks like there are some constraints on
>     blind/buried vias (microvias are blind/buried
>     >>> vias) depending on board houses.
>     >>>
>     >>> So it could be worth to be able to control these constraints
>     inside Kicad (at least to have a
>     >>> minimal control).
>     >>>
>     >>> We currently have a DRC which detects too small clearances and
>     track widths:
>     >>> this is most of time due to manufacturing constraints which
>     continuously evolve.
>     >>>
>     >> I don't think I have enough understanding of the proposal to have an
>     >> opinion. I just want to caution against creating unnecessary
>     >> limitations in kicad. It really depends on the board house. I used to
>     >> work for one and there were quite a few atypical techniques used for
>     >> customer specific projects (many kept confidential to that customer).
>     >>
>     >>
>     >>
>     >>
>     >>
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> 
>     --
>     Jean-Pierre CHARRAS
> 
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