kicad-developers team mailing list archive

[Miguel Angel Ajo Pelayo <miguelangel@xxxxxxx>]

2012/7/31 Lorenzo Marcantonio <l.marcantonio@xxxxxxxxxxxx>

> On Tue, Jul 31, 2012 at 08:05:07AM +0200, Miguel Angel Ajo Pelayo wrote:
> > 1) Silkscreen vs Soldermask
>
> What do you see which isn't poking you in an eye xoring the two gerbers?
>

Why make things complicated when you could see it one-click away? (well, it
makes sense on my al*um package where the 3d render helps a lot), I think
gerber xoring is easier than brd->eup->sketchup->render :-D




>
> > 2) Silkscreen alignment can be seen much more clearly
>
> Please tell me what you mean with silkscreen alignment, I simply don't get
> it... also at the end silk is mostly eaten away by registration clearances
> (in practice everything smaller than 0805 is silkless). When you have
> components packed on a 0.5mm grid there isn't a lot of place for silk! Also
> assembly is 95% automated, most of the board we make has no silk at all.
>


I mean about easy finding things like this, this is 0603, and It's not
silkless, silkless would make the pcb very hard to repair. I agree that, if
you go HDI, then you will end silkless :-)

[image: Imágenes integradas 1]


>
> > 3) You can add your mechanical case and check if all the connectors match
> > their holes and if all the holes in the PCB match the screw supports
> > correctly.
>
> You have a point with that, but then you'll need *accurate* connector
> models which are a) supplied only by some manufacturers (especially Molex
> and TE) and b) in STEP or IGES
>

That's changing a lot, most manufacturers start to provide STEP + IGES,
Würth does, (I do, and I'm tiny-nothing!),  farnell is plagued with 3D
models now :-)


>
> Actual workflow varies depending on if you design the enclosure on the pcb
> or you have to fit the pcb in an enclosure (luckily for me it's mostly the
> former)
>

I'm my workflow it's usually a mix of both, and for no-professional-usage I
suppose people will want to fit board to enclosure.


>
> For now pcb holes can be matched with the dxf plots.
>

It's a good way also :)


>
> > The ideal would be plain step exporting from a pcb file, but we will have
> > that sooner or later :-)
>
> Some volunteer can try to wrangle opencascade which, AFAIK, is the only
> open
> source stuff handling STEP around.
>
> >     I think I've never made a 3D model for a component, but I use them a
> > lot.
>
> I stopped when I noticed that I was using more 'strange' components than
> available ones... think about it, you actually don't need for the above
> reason all the chip parts and most of the jedec cases... you need a)
> connectors and b) big/strange stuff (like vertical modules, relays and
> transformers). Sadly most of these are not standardized... heck, even a
> plain DE9 connector can have about 6 different profiles!
>
> >     In other packages I import all the STEP files that the component part
> > manufacturers provide. It really helps to check your silkscreen overlay,
> > and to check you footprint holes :-), It also helps to check if your
> > connectors are colliding to any surrounding element.
>
> You are lucky to find all the STEPs then. On the last board I've done only
> about 30% of the connectors had STEPs around (yes, it has a *lot* of
> different connectors:D). In fact for one of them we need to delay the
> enclosure waiting for prototypes since even the drawing on the datasheet is
> clear... we don't actually know how the fscking thing protrudes from the
> board!
>

Some datasheets are awful :-), they make me think that either the drawer
was totally unexperienced or I'm dumb reading them.


>
> >    Once you start, you get somehow "addicted" to its benefits.
>
> Maybe with a full 3D workflow (ECAD included) it could work *if* there
> were all the resources available. And especially a static render is only
> eye candy for me:D
>

Well, for static yes, but in sketchup you can move everything around :-),
not only static render it (which is eye candy) :)  , even sometimes is
dangerous, if you get a extra-beautiful render (using keyshot for example),
and the final result is not that pretty... :)


>
> --
> Lorenzo Marcantonio
> Logos Srl
>
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-- 

Miguel Angel Ajo Pelayo
http://www.nbee.es
+34 636 52 25 69
skype: ajoajoajo