Mark,
Our in-house assembly wants .015" spacing on pad-pad and pad -trace.

Mark


> -----Original Message-----
> From: Mark Holmes [SMTP:[log in to unmask]]
> Sent: Thursday, August 03, 2000 11:08 AM
> To:   [log in to unmask]
> Subject:      [DC] Pad to Pad Spacing for Surface mount parts.
>
> Hi all,
>
> What guidelines do you follow for the placement of surface mount parts?
> (by
> this I mean the pad to pad spacing)
> I have in front of me  IPC-SM-782A which seems particularly vague in this
> area. It recommends 0.040" side by side
> pad to pad spacing (for what appear to 0805 type parts) and 0.025" for end
> to end spacing. I regularly go much closer
> than this. I would be most interested to hear what sort of clearances
> designers out there are really using (for reflow soldering).
>
> Our placement machine is able to place parts incredibly close, and I have
> never experienced and problems with placement accuracy.
> I assume that the soldering process has the biggest influence on pad to
> pad
> clearances.
>
> Thanks in advance,
>
> Mark.
>
> Mark Holmes PCB Designer
> Helvar Merca Ltd.
> Hawley Mill, Hawley Road,
> Dartford Kent. DA2 7SY
> Tel: 01322 222211
> Fax: 01322 282286
> mailto:[log in to unmask]
> http://www.helvar.com