I thought they called them that, because every time I questioned them, they
recanted their story.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Paulus, Jim
Sent: Wednesday, September 08, 2004 7:43 AM
To: [log in to unmask]
Subject: Re: [TN] Wavy Holes.
Back in the halycon days of double-sided being the dominant technology,
we laminators used to have a little problem (our problems were always
"little anomalies", our customers' problems were always "serious
deficiencies in their process") with something called canted holes.
The holes especially seen after plating would have settled to a definite
angle of 5-10 degrees from vertical, and leaving a surface lip on one
side of the hole. It was due to undercured laminate, which would result
in the plies slipping sideways during the fab process
Does the wavy condition correlate to the prepreg plies -- it might be a
lamination issue.
Jim Paulus
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ingemar Hernefjord
(KC/EMW)
Sent: Wednesday, September 08, 2004 1:22 AM
To: [log in to unmask]
Subject: Re: [TN] Wavy Holes.
Dave,
If you have Puligandla Viswanadham's book Failure Modes and Mechanisms
in Electronic Packages, you may find an explanation. On page 164 he
shows something that reminds of your wavy PTH. He speaks about a
combination of rough drilling, delamination, copper barrel spiral
cracking and finally, the solder's inability to wet this messy barrel
properly. The result can be a wavy PTH.
Ericsson Microwave Systems
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Dave Simonik
Sent: den 3 september 2004 17:40
To: [log in to unmask]
Subject: [TN] Wavy Holes.
Technetters;
One of those Friday questions: Has anyone seen, experienced, or dealt
with 'wavy' through holes in thick backplane type pcb constructions? I
have
searched the Technet archives, but came up empty handed.
We have begun to see this phenomenon on some of our tougher thick
constructions, and we are scratching our heads in trying to define the
root
cause of this issue. The holes appear somewhat like this after drill:
| |
\ \
/ /
| |
/ /
\ \
| |
We have seen this on hole sizes .020" - .032". We have begun to set up
some DOE's. Even our tool supplier is lost for words, trying to imagine
how
such a large tool can 'wave' like that during the drill cycle.
If anyone wants further details, please contact me offline. I have
many
digital photo's of this issue if anyone wants to offer their services in
posting a picture on a web site.
Thank you.
David R. Simonik
------------------------------------------
Laser Engineering Technician
Sanmina - SCI Corporation
Owego NY Division
1200 Taylor Rd. Owego NY 13827
Office: 607-689-5609
Fax: 607-689-5909
<mailto:[log in to unmask]
<mailto:[log in to unmask]> >
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