http://www.circuits-expert.com/art/thick-copper-layers-in-printed-circuit-boards-application-and-design-13

> a bit tough if pressure is low... and time is short.  imho.
>> The copper is 1.5-oz. on the outer layers, and 1-oz. on inner layers.
>>
>>
>> Carl B. Van Wormer, P.E., AE7GD
>> Senior Hardware Engineer
>> Cipher Engineering LLC
>>     21195 NW Evergreen Pkwy Ste 209
>>     Hillsboro, OR  97124-7167
>>     503-617-7447x303
>>     [log in to unmask]     http://cipherengineering.com
>>
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
>> Sent: Wednesday, April 26, 2017 7:48 AM
>> To: [log in to unmask]
>> Subject: Re: [TN] PCB delamination at area with ground-plane cutout
>>
>> what is the copper thickness?
>>> I have to wonder why the plane was pulled back.  Looks like a DB9, so
>>> I'm thinking, low speed signals, possible RS232.  But it could be some
>>> high impedance circuit where capacitive loading is a big problem.
>>> Perhaps not.
>>>  Perhaps the pullback was done not to limit capacitive effects on the
>>> traces on that DB9, just a pullback to prevent coupling, as a plane
>>> wasn't required.  Just guessing, so as to not impact circuit
>>> performance.
>>>
>>> If low capacitance is required, it might be a bit more work than just
>>> adding a split plane or thieving, as it couldn't be added under the
>>> traces--but it could be brought "near" for the desired effect.  But if
>>> it was just a "we don't need a plane here, just remove it" then a
>>> split plane should be easy enough to use, with a full or crosshatched
>>> pour.
>>>
>>> Shawn Upton
>>> Section Head, Test Engineering
>>> Sensors Business Unit
>>> Allegro MicroSystems, LLC
>>> [log in to unmask]
>>> 603.626.2429/fax: 603.641.5336
>>>
>>>
>>> -----Original Message-----
>>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Carl Van Wormer
>>> Sent: Wednesday, April 26, 2017 9:51 AM
>>> To: [log in to unmask]
>>> Subject: [TN] PCB delamination at area with ground-plane cutout
>>>
>>> We received pictures from our contract manufacturer, marked to show
>>> delamination occurring in 2 areas on our 6-layer boards.  The
>>> delamination areas were at the electrically isolated communication
>>> interfaces that were made with no copper on the power and ground
>>> planes to reduce capacitive coupling.  The response from the PCB
>>> manufacturer is:
>>>
>>> ​​​​​1)defect reason: we used our
>>> stock boards to run the
>>> thermal shock test, we see the de-lam is only taking place in the two
>>> areas without copper (pic 1.jpg),
>>>     There is insufficient glue in this area that happened during
>>> lamination and that is why the de-lam is happening when the customer
>>> is assembling under the high temp, 2)correction action:  if the
>>> customer needs us to remake, we suggest to modify the design a little,
>>> pls see pic 2.jpg, we will fill the marked area with solid copper .
>>> Please confirm if a remake is needed, we will arrange right away.
>>>
>>> Steve Gregory has posted the pictures at:
>>> http://stevezeva.homestead.com/Carl1.jpg (board cut open for
>>> evaluation at board house)
>>>
>>> http://stevezeva.homestead.com/Carl2.jpg (picture showing where they
>>> want to add copper)
>>>
>>> (and 2 pictures of the delaminated areas)
>>> http://stevezeva.homestead.com/Delamination_-_is_it_caused_by_missing_
>>> ground_plane__1_.jpg
>>> http://stevezeva.homestead.com/Delamination_-_is_it_caused_by_missing_
>>> ground_plane__2_.jpg
>>>
>>>
>>> Question to the group:  Will adding copper on the electrically
>>> isolated open areas eliminate this type of delamination?  We could add
>>> the copper, but not connect it to the system ground.
>>>
>>> Thanks,
>>> Carl
>>>
>>>
>>>
>>>
>>>
>>>
>>> Carl B. Van Wormer, P.E., AE7GD
>>> Senior Hardware Engineer
>>> Cipher Engineering LLC
>>>     21195 NW Evergreen Pkwy Ste 209
>>>     Hillsboro, OR  97124-7167
>>>     503-617-7447x303
>>>     [log in to unmask]<mailto:[log in to unmask]>
>>> http://cipherengineering.com<http://cipherengineering.com/>
>>>
>>> This message may contain confidential and/or proprietary information,
>>> and is intended for the person/entity to whom it was originally
>>> addressed. Any use by others is strictly prohibited.  If I sent this
>>> to you by mistake, please be nice and delete it, and then tell me of
>>> my mistake so I can send it to the right person.
>>>
>>>
>>>
>>
>
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