Werner, all

It is also my opinion (not my companies') that the new slash sheets are
worse
than useless. The minimum values for several key properties such as Td
and T288 have been REDUCED to a level that any of these materials can
meet but which is below what is necessary for reliability at or after LF
soldering temperatures.

IF any designer out there is thinking that they can put a slash sheet
number
on their drawing as a requirement for the laminate which would ensure
some minimal degree of suitability for use, they are wrong - that won't
be good enough.

Sorry to have to say it, but I believe it to be true: the laminators have
succeeded in having specs written which are slam-dunks for them but
leave the product at risk.

Valerie





Werner Engelmaier <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
12/12/2005 07:16 PM
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Subject
Re: [TN] Qualification of the Pb-free capable manufacturers




>>> snip
The slash sheets for laminate/prepreg materials given in IPC-4101 are so
wide
open in the ranges of properties that they are in fact useless. New slash
sheets   IPC-4101B/99, /101, /121, and /124 have been proposed for use for
LF-soldering--again, the property ranges are much too wide to be useful
for any
designer.  <<<

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com



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