Whoops ! Now I'm definitely confused ;
I thought (down here it's all upside down) we talk about solder mask
blistering off the copper .
Somehow delamination didn't click with measling ;
so solder mask blisters is different cat of fish .
Therefore delamination is called measling and mask blistering has any other
tags ?
Thanks paul
-----Original Message-----
From: Kelly M. Schriver [mailto:[log in to unmask]]
Sent: Wednesday, 2 February 2000 22:29
To: [log in to unmask]
Subject: Re: [TN] Measling
Whoops!! Help me with this one, guys!! Measling, by definition, occurs
only at the intersection of two fiber bundles within the lamina.
Accordingly, it cannot occur in the same plane as the metal foil of that
laminate layer. The size of a measle is self limiting by the structure of
the glass (or fiber) bundles. Further, one measle cannot join with an
adjacent measle or become a running fault in the laminate.
Crazing and delamination, however, can occur in the same plane as the metal
foil, and can become large running or bridging faults. I've seen numerous
cases of crazing which were misdiagnosed as measling.
Many of the publications, such as WS6536, MIL-STD-2000 and others failed to
recognize this charactaristic about measles vs other internal laminate
faults, leading to a few misconceptions. I have seen no indication of test
data, other than some specialized high power applications which suggests
that real bona fide measles are a reliability problem.
Regards - Kelly
-----Original Message-----
From: rampinc <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Tuesday, February 01, 2000 6:39 PM
Subject: Re: [TN] Measling
>Rick,
>
>Be careful. Measling can be a source of reliability problem when it bridges
two
>conductors. Measling becomes 'A' type defect ( Critical function -causing
rejection)
>when two conductors of different polarity are bridges. If glass fibers
become visible
>in a measled spot, that is also a cause for concern.
>
>Send pictures of measled board for further discussion if you like.
>
>"Howieson, Rick" wrote:
>
>> IPC states measling is not cause for rejection. Anyone out there know
>> where I can get supporting data that documents testing performed to come
>> to this conclusion? All help is appreciated.
>>
>> Rick Howieson
>> http://www.gt-corp.com
>>
>> ##############################################################
>> TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
>> ##############################################################
>> To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in
>> the body:
>> To subscribe: SUBSCRIBE TECHNET <your full name>
>> To unsubscribe: SIGNOFF TECHNET
>> ##############################################################
>> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
>> information.
>> If you need assistance - contact Gayatri Sardeshpande at [log in to unmask]
or
>> 847-509-9700 ext.5365
>> ##############################################################
>
>--
>____________________________________
>Regards,
>Pratap Singh
>
>Tel./Fax: 512-255-6820,
>e-mail: [log in to unmask] or [log in to unmask]
>
>##############################################################
>TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
>##############################################################
>To subscribe/unsubscribe, send a message to [log in to unmask] with following
text in
>the body:
>To subscribe: SUBSCRIBE TECHNET <your full name>
>To unsubscribe: SIGNOFF TECHNET
>##############################################################
>Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
>information.
>If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
>847-509-9700 ext.5365
>##############################################################
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following
text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################
|
