RussellMc wrote:
>>> Equating CEM-3 and FR4 is not encouraging as the two are fundamentally
>>> different in layup PLUS use different chemistry resins.
>>> I posted a longish post a few months back covering matters related to
>>> different PCB materials and characteristics. It included some reference=
s and
>>> may be worth looking at. I've just reposted it under subject line Re: [=
EE];
>>> PCB Materials (was Parallel passives and sprinkled vias?)
>>>      =20
>> Everything I've seen, dozens of boards from Gold Phoenix in the last
>> couple years has been what appears to be real FR-4.
>> I've not noticed any copper pull-up problems on boards that are gently
>> reworked a couple times. When you start getting into higher
>> temperatures, larger parts, larger holes, there are always issues with
>> reworking too much.
>>    =20
>
> Good to hear re GP.
> Interestingly, he notes that PCB's from Eurocircuits do not have the
> same problem.
> Murphy says that there may be relevant missing information but it does
> sound from what's said that E' do something differently.
>  =20
Personally I suspect he just got a bad batch. While GP are cheap and=20
generally provide good boards I think thier quality control may leave=20
something to be desired. I know someone at uni got a four layer board=20
from them supposedly electrically tested but that turned out to have a=20
load of bad vias on it.
>
>       Russell
>  =20

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.