sometimes the pcb faber will try to plate up one ounce to two ounce not
always good  do a cross   section  of the plane and look for separation

> -----Original Message-----
> From: Stephen R. Gregory [SMTP:[log in to unmask]]
> Sent: Wednesday, October 06, 1999 12:57 PM
> To:   [log in to unmask]
> Subject:      [TN] Two distinct layers of copper...
>
> Hi ya'll!
>
> Here's something weird I've never come across, but maybe some of you have.
> We
> built this Hi-Rel board here that the PCB drawing calls out for 2-ounce
> copper.
>
> The board has this leaded SMT multi-capacitor part (it's like 3 huge
> ceramic
> capacitors stacked on top of each other) and has 8-leads. After assembly,
> and
> before we test then conformal coat it, we put the assembly on this
> vibration
> table to go through some ESS.
>
> There's been a few of these capacitor deals come loose because they're so
> top
> heavy, but that's a whole 'nuther issue...
>
> What we've been seeing on some of these boards, is that either the pad
> completely lets go from the laminate (it's a polyimide), or sometimes
> we'll
> see the pad come up in what looks like a layer of copper, yet there's
> still
> copper down on the PCB...as if the copper has split horizontally in two
> distinct layers? Is this possible? Does 2-ounce copper clad laminate get
> the
> copper plated an ounce at a time? Is this a defect? I've never seen
> something
> like this before, and I can take a picture and send it to ya' if you want
> me
> to....
>
> Thanks!
>
> -Steve Gregory-
>
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