Hi Wayne! I did not specify the material, I just know what it is! We'll
need some of the TechNet pwb crew to offer up "why" a conductive filler
material would be advantageous.
Dave
Wayne Thayer
<WTHAYER@EVITECHN
OLOGY.COM> To
Sent by: TechNet [log in to unmask]
<[log in to unmask]> cc
Subject
05/23/2006 08:39 Re: [TN] Thermal cycle test for
AM plated through holes filled with
epoxyink and cap plated on
Please respond to
TechNet E-Mail
Forum
<[log in to unmask]>
; Please respond
to
Wayne Thayer
<WTHAYER@EVITECHN
OLOGY.COM>
Making continuity because of conductive filler wouldn't give me "warm
fuzzies" about the boards. If conductive filler were really good for
anything besides improved thermal conductivity, why do the manufacturers
of it recommend plating prior to filling?
Wayne
>>> [log in to unmask] 5/23/2006 9:01:42 am >>>
Hi gang! Another possibility would be if the fill material for the
plated
thru holes is conductive (e.g. CB100 which is silver filled). The test
might register a "false positive" with the barrel cracking but the
electrical continuity being maintained by the conductive hole
material.
Dave Hillman
Rockwell Collins
[log in to unmask]
Jeffrey Bush
<Jeffrey.Bush@VTC
IRCUITS.COM>
To
Sent by: TechNet [log in to unmask]
<[log in to unmask]>
cc
Subject
05/23/2006 07:24 Re: [TN] Thermal cycle test for
AM plated through holes filled with
epoxy ink and
cap
plated on the top
Please respond to
TechNet E-Mail
Forum
<[log in to unmask]>
; Please respond
to
Jeffrey Bush
<Jeffrey.Bush@VTC
IRCUITS.COM>
Is it possible the pattern has redundant chains supporting continuity
after
some have cracked? Cracked barrels generally produce resistance
levels
well above 5%.
Jeffrey Bush
Director, Quality Assurance and Technical Support
VERMONT CIRCUITS INCORPORATED
76 Technology Drive - POB 1890
Brattleboro, Vermont 05302
Voice - 802.257.4571 ext 21
Fax - 802.257.0011
<http://www.vtcircuits.com/>
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of christian ge
Sent: Tuesday, May 23, 2006 2:53 AM
To: [log in to unmask]
Subject: [TN] Thermal cycle test for plated through holes filled with
epoxy
ink and cap plated on the top
Hello Technetters,
I need your help on the following thermal cycle test problem.
Recently we asked our PCB suppliers to do 1000 cycle thermal cycle
test
for 6L, daisy chain boards with plated through holes filled with epoxy
ink
and cap plated on the top of the holes( or via-in-pad design). The
resistance change before and after thermal cycle test is less than 5%,
however the holes have complete barrel crack. Have you seen this kind
of
problem before? Can I approve the supplier's test result?
Here are some more information about the test for your reference.
1) board thickness: 1mm (40mils)
2) hole size: 20mils, 18mils, 15mils, 10mils. All have complet
barrel
crack except the holes of 10mils .
Thanks for your help in advance!
Chris
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