I have adjusted my silkscreen on these parts to accommodate the closer
grouping. This allows me to place them closer but it violates the IPC
spacing rules. Only a few houses have commented on this practice.

----- Original Message -----
From: "John Haddy" <[EMAIL PROTECTED]>
To: "Protel EDA Forum" <[EMAIL PROTECTED]>
Sent: Tuesday, 10 April, 2001 7:41 PM
Subject: Re: [PEDA] Creating custom design rules?


> However, the coponent clearance rule is next to useless once
> you start working with tightly packed boards. If you want to
> place componnets so that their silkscreen borders overlap
> (e.g. 0402s places side by side), you need to turn off the
> component clearance rule - so you end up with the very dangerous
> situation of requiring manual checking of each and every component
> placement.
>
> I've said this before (but I'll repeat it in the hope that someone
> at Protel listens :-):
>
> What is really needed is an extra layer defined as a physical
> component outline layer. A clearance rule based on this layer would
> ensure that components did not try to physically occupy the same
> space. This rule would need to be combined with clearance rules that
> would ensure minimum gap between a primitive entity (e.g. pad, or
> a soldermask opening) and entities on the silkscreen layer (so that
> one component's legend doesn't end up over a pad).
>
> It is getting very rare, with the boards that I work on, that the
> silkscreen overlay bears any resemblance to the actual component
> outline - so using this as the rule to prevent component interference
> is not useful.
>
> Just my $0.02c
>
> Cheers,
>
> John Haddy
>
>
> > -----Original Message-----
> > From: Ian Wilson [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, 11 April 2001 10:00 AM
> > To: Protel EDA Forum
> > Subject: Re: [PEDA] Creating custom design rules?
> >
> >
> > On 05:06 PM 10/04/2001 -0600, Gladieux, Jed said:
> > >Does anyone know how to create new design rules.  For example, I
> > would like
> > >to flag instances where component outlines on the silkscreen
> > layers overlap.
> > >
> > >
> > >I got bit by this on a very busy board and wound up with 2 components
> > >physically interfering with each other although pads/tracks were all
OK.
> > >
> > >I'm currently using Protel98 but am planning to migrate to 99SE
> > as soon as I
> > >get a chance.  Wasn't able to find anything in P98 Help.  Maybe I'll
try
> > >Protel's Knowledge Base, but in the meantime, it anyone knows
> > how to do this
> > >I would appreciate any advice.
> > >
> > >TIA,
> > >
> > >Jed Gladieux
> >
> > In P99SE you can set a rule for component clearance.  If you set
> > the Check
> > Mode to Full and the clearance of 0mil/mm you will get an
> > accurate check of
> > interference even for convoluted component outlines - assuming
> > your overlay
> > details are correct.
> >
> > P98, from memory, does not have the full check mode and it
> > doesn't have the
> > same method of setting component clearance.  Anyway P99SE should
> > go someway
> > to trapping your problem.
> >
> > Ian Wilson
> >
> >
>
>


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