Madhu,
I agree with Hans, it is going to warp... sequential lamination may improve
it some but the risks may be too great. What we've done in these type
situations are
1. Suggest an improved layup that will reduce the likelihood of warpage
2. Ask the customer to sign, or acknowledge the product may indeed have warp
and they will not reject them back to you for the warp, and if one of those
don't work
3. Refuse to take the order...
Franklin
----- Original Message -----
From: "Hinners Hans M Civ WRALC/LUGE" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, April 23, 2003 8:09 AM
Subject: Re: [TN] Warpage
> Hi Madhu,
>
> Have you tried sequential lamination? Everything below the dummy core is
> symmetrical.
>
> Does the warp get worse after route?
>
> I'd also confirm good heat distribution in the hot & cold press pallets.
I
> wouldn't be too aggresive with the cool down cycle - it might make the
warp
> worse.
>
> You could try cross ply prepreg if it's available from your supplier.
>
> First look, I'd say that panel is gonna warp no matter how you process it.
>
> Hans
>
> -----Original Message-----
> From: [log in to unmask]
> [mailto:[log in to unmask]]
> Sent: Wednesday, April 23, 2003 3:04 AM
> To: [log in to unmask]
> Subject: [TN] Warpage
>
>
> Fellow technetters,
>
> I am back with the same old problem: bow & twist
>
> we are producing a 14 layer , cap lamination board for one of our
customer
>
> the construction is as shown below:
>
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 1080
> - - - - - - - - - - - - - - - - - - -
> ************************** 28 mil dummy core
> - - - - - - - - -- - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 2116
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 1080
> ^^^^^^^^^^^^^^^^^^^ 2116
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 1080
> ^^^^^^^^^^^^^^^^^^^ 2116
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 1080
> ^^^^^^^^^^^^^^^^^^^ 2116
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 1080
> ^^^^^^^^^^^^^^^^^^^ 2116
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
> ^^^^^^^^^^^^^^^^^^^ 1080
> ^^^^^^^^^^^^^^^^^^^ 2116
> - - - - - - - - - - - - - - - - - - -
> ************************** 3 mil core
> - - - - - - - - - - - - - - - - - -
>
> Obviously, we are getting warpage in boards
> the construction is customer given and he is not ready to change this
>
> Are there any solutions to avoid warp in these boars
>
> cheers,
> Madhu
>
>
>
>
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