Yes, you are right. I was being harsh, sorry.
I just didn't want anyone to get the wrong impression
that using thick copper was a bad idea or dangerous
or something, because we do it all the time.
I'm embarrassed that I can't find that chart, it shows
how much trace/space you need for different copper
thicknesses. If anyone has it, please post it, ok?
Jack
(the "usually organized paperless office" kinda guy)
Billy Bharath
<[log in to unmask]
za>
To
04/06/2005 10:11 To
AM "'Jack C. Olson'"
<[log in to unmask]>
"(Designers Council Forum)"
<[log in to unmask]>
Billy Bharath <[log in to unmask]>
cc
Subject
RE: [DC] PCB TECHNOLOGY (2 oz
copper)
Caterpillar: Confidential Green Retain Until: 05/06/2005
Retention Category: G90 -
General
Matters/Administration
I dont understand why you would say this is a misleading response, your
statement supports my experience the thicker the copper the wider the
spacing, therefore based on my spacing (5 thou) the manufacturer could not
(they probably can now) successfully produce a 16 layer using 1 ounce on a
1.6 material.
The educational trip was usefull
Billy
-----Original Message-----
From: Jack C. Olson [mailto:[log in to unmask]]
Sent: Wednesday, April 06, 2005 4:57 PM
To: (Designers Council Forum); Billy Bharath
Subject: Re: [DC] PCB TECHNOLOGY (2 oz copper)
I think this is a misleading response.
The problems you describe are not from
using thick copper, it's from having too
many layers of thick copper crammed into
a specified final thickness. Of COURSE
14 layers of 2oz would be impossible,
that's over 40mils of metal in a 62mil
stackup! (counting the surface plating)
ridiculous!
Since the layer count was not specified,
the 14layer example is not necessarily
relevant, sorry to sound like a bee-otch
<grin>
We use 2oz copper on probably 95%
of our boards with no ill effects. The
primary consideration would be your
trace width and space clearances, for
thicker copper you need more room to
work. For 2oz I wouldn't go below 6/6
without talking to your vendor, and for
more I would add another mil per ounce
I have a chart here somewhere, but I
can't seem to find it right now (I have
never gone above 2oz) If I find it I'll
post it.
Jack
Billy Bharath
<[log in to unmask]
ZA>
Sent by: To
DesignerCouncil To
<DesignerCouncil@ [log in to unmask]
ipc.org> cc
04/06/2005 07:33
AM
Subject
Please respond to Re: [DC] PCB TECHNOLOGY (2 oz
"(Designers copper)
Council Forum)"
<DesignerCouncil@
IPC.ORG>; Please
respond to
Billy Bharath
<[log in to unmask]
ZA>
Caterpillar: Confidential Green Retain Until: 05/06/2005
Retention Category: G90 -
General
Matters/Administration
Hi,
Many years ago(+/- 6 years) we designed 14 layers into a 1.6 thick pcb
using
1 ounce copper on the internal layers, sadly the manufacturing houses
experienced "copper spreading" on the internal layers. The explanation
provided was that squeezing 14 layers into 1.6mm pcb was causing the
internal layer copper to spread sideways. We were than advised to consider
0.5 ounce(17u) copper. We changed to 0.5 ounce and NEVER had a problem
since. Using that as an argument I would than assume using 2 ounce copper
could have made that pcb almost impossible to manufacture, than again it
also depends on the number of layers.
regards
Billy Bharath
-----Original Message-----
From: Sanchez-Benavides Erika
[mailto:[log in to unmask]]
Sent: Wednesday, April 06, 2005 2:12 PM
To: [log in to unmask]
Subject: [DC] PCB TECHNOLOGY (2 oz copper)
Hello all,
One of our PCB suppliers came out with a PCB design that have 2 ounces
of copper on all layers. Until now we have worked with PCB that have 2
ounces of copper only on the exterior layers, and only one ounce of
copper on the interior layers.
We do not have experience working with PCBs with 2 ounces of copper on
all the layers.
Would you mind helping us to gain more knowledge regarding these PCBs?
Are there any risks associated with this design: thermal events,
concerns, things that we should be aware of?
Thanks in advance,
..........................................................
Kind regards
Erika E. Sanchez
PCB Designer
Siemens VDO
Internet: http://www.siemensvdo.com
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