Blair: 
Wish you were here. Left Allentown with cars and trucks parked on I-78 in 50
mile failure of PennDot. 

APEX. LA. 87° yesterday, a pleasant 70 today (Of course we are working both
Saturday and Sunday). . . but then, Blair,  there is the time stamp on your
post. I hope your sacrifices are appreciated. 

Ioan: 

The land pattern is merely a feature, an extension of a trace, it is
surrounded by solder mask, on which the component must rest. I don't think
it is reasonable to think of the area under a component as a keep out. We
are way past that, consider LGAs. 

We really must direct our attention other requirements of the design. What
is the thickness of the copper? What type of solder mask (thickness
dielectric, coating proprieties) ? What are the process implications,
printing, placing, reflow, cleaning?  

I don't think there will be any relief for in a standard. If I can take the
words of Edward Deming out of context, ". . . substitute leadership". 

Sorry, Ioan.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Hogg, Blair K.
Sent: Sunday, February 18, 2007 10:44 AM
To: [log in to unmask]
Subject: Re: [TN] Traces between 0402 pads

Our process engineer has a conniption when the designers put traces between
the pads (under the component) on 1206 and 0805 components. He claims that
the thickness of the copper and soldermask may be enough to hit the bottom
of the component and cause problems in soldering.
 
Blair

________________________________

From: TechNet on behalf of Tempea, Ioan
Sent: Fri 2/16/2007 8:39 AM
To: [log in to unmask]
Subject: Re: [TN] Traces between 0402 pads



> Dear colleagues,
>
> is there any standard saying that traces should not be routed between 0402
pads, i.e. under the component? I have a serious discussion and really need
to back it up with a formal document.
>
> Thanks,
>
> Ioan

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------