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May 2012

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Subject:
From:
Steve Gregory <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Steve Gregory <[log in to unmask]>
Date:
Tue, 1 May 2012 10:28:09 -0400
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Hi Richard,

I just looked closely at some product that we were running today that's
using a 4-mil stencil (with no homeplates), and I don't see any mid-chip
solder balls, and I looked at where they would most likely occur if there
were to be any:

http://stevezeva.homestead.com/4-mil_no_homeplate.JPG

I can't say that we NEVER have any, sometimes it happens, like when the
wrong sized part is used on a footprint designed for something else (oh
wait, that never happens!). But overall, usually don't see them when we use
a 4-mil thick stencil.

Steve

-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]] 
Sent: Monday, April 30, 2012 3:56 PM
To: TechNet E-Mail Forum; Steve Gregory
Subject: RE: [TN] Homeplates on 4 mil thick stencils?

Steve,
Somewhat related to the other discussion on cleaning of no-clean:
Do you wash the assemblies after reflow, and is that why you do not see any
mid-chip solder balls?
Do you wash any CCAs that have been processed with a no-clean solder paste
or no-clean wire solder?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Monday, April 30, 2012 2:42 PM
To: [log in to unmask]
Subject: Re: [TN] Homeplates on 4 mil thick stencils?

BTW I forgot to add I don't homeplate anything...

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Monday, April 30, 2012 3:16 PM
To: [log in to unmask]
Subject: Re: [TN] Homeplates on 4 mil thick stencils?

Hi Ioan,

We use 4-mil thick stencils quite often and I don't see mid-chip balling...

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: Monday, April 30, 2012 2:54 PM
To: [log in to unmask]
Subject: [TN] Homeplates on 4 mil thick stencils?

Dear Technos,

 

It is my first 4 mil stencil and I was wondering if mid-chip balling is
still an issue at this thickness (no-clean process). Should I still
homeplate the apertures of passives, as I fear insufficient solder?

 

Thanks,

 

Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer T |
450.967.7100 ext.244 E | [log in to unmask] <mailto:[log in to unmask]> W |
www.digico.cc <http://www.digico.cc/> 

 
 N'imprimer que si nécessaire - Print only if you must

 


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