What about (bad word) conformal coating?
Bob Croslin
Nielsen Media Research
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Leo Higgins
Sent: Wednesday, August 15, 2007 12:05 PM
To: [log in to unmask]
Subject: Re: [TN] Solder mask as an insulator
Would it be possible to stencil print, or dispense dots of an
appropriate epoxy paste to form small mechanical stand offs only at the
location of the offending PTH components?
Best regards,
Leo
Leo M. Higgins III, Ph.D.
Sr. Vice President, Engg and Technology
ASAT, Inc.
13809 Research Blvd., Suite 635
Austin, Texas 78750
office phone 512-249-4758
mobile 512-423-2002
[log in to unmask]
www.asat.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Phil Nutting
Sent: Wednesday, August 15, 2007 9:59 AM
To: [log in to unmask]
Subject: [TN] Solder mask as an insulator
Let me start with, I know that we should not rely on the LPI solder mask
as an insulator. So I need recommendations for a simple and cost
effective solution.
Problem parameters; 0.062 thick FR-4 with 2 oz copper and LPI mask. PTH
components laying on traces that go under the parts. PTH parts are
shorting to the traces.
Our fab house is against adding a second layer of LPI mask. On face
value a second layer sounds good and easy, but I know there are issues
too long to list.
Short of raising the components above the board, applying an insulator
under the components or a new board layout is there a better way of
preventing this shorting problem?
Thanks in advance.
Phil Nutting
Design for Manufacturing Engineer
Kaiser Systems, Inc.
126 Sohier Road
Beverly, MA 01915
voice: 978-922-9300 x1310
fax: 978-922-8374
e-mail: [log in to unmask]
www.kaisersystems.com
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