> -----Original Message-----
> From: PowerSmart [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, 11 April 2001 11:56 AM
> To: Protel EDA Forum
> Subject: Re: [PEDA] Creating custom design rules?
> 
> 
> 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.

With small components, I need the silkscreen as close as possible to the
pad (dictated by the fabricator's manufacturing tolerance on silkscreen
positioning), PLUS I want to overlap adjacent component overlay traces.
I regularly need 0402s placed on a 1mm pitch, for example.

If I could guarantee that every board would be fully machine assembled,
I could get away with removing the silkscreen entirely. Unfortunately,
I need hand placement for prototypes and a sea of pads without bounding
boxes to guide a human is just asking for trouble. So, if I must have
overlay present, I don't want it interfering with my placement any more
than absolutely necessary.

John Haddy

Cisco Systems WNBU
Level 2, 3 Innovation Rd; North Ryde NSW 2113; Australia
PO Box 617; North Ryde NSW 1670; Australia
Phone: +61 2 8874 5406; Fax: +61 2 8874 5401


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