 
| Mime-Version: |
1.0 |
| From [log in to unmask] Thu Mar 13 12: |
56:13 1997 |
| Old-Return-Path: |
|
| Date: |
Thu, 13 Mar 1997 09:04:57 -0500 (EST) |
| Precedence: |
list |
| Resent-From: |
|
| Resent-Sender: |
|
| X-Status: |
|
| Status: |
O |
| X-Mailing-List: |
|
| X-Sender: |
|
| TO: |
|
| Return-Path: |
<TechNet-request> |
| X-Loop: |
|
| Resent-Message-ID: |
<"WVJoR3.0.NI6.yR0Ap"@ipc> |
| Subject: |
|
| From: |
|
| Received: |
by ipc.org (Smail3.1.28.1 #2)
id m0w5AxJ-000BBvC; Thu, 13 Mar 97 07:54 CST |
| Content-Type: |
text/plain; charset="us-ascii" |
| X-Mailer: |
Windows Eudora Pro Version 2.1.2 |
| Message-Id: |
|
| Parts/Attachments: |
|
|
John ..
CTE (coefficent of thermal expansion) & dielectric constant typically
increase above the glass transition ... mechanical strength decreases ...
the lap shear strength of an epoxy resin that is 4500 psi at room
temperature can decline to less than 200 psi above its glass transition.
Delamination of cured composite laminates above the glass transition is a
reality. At least for most applications, delamination and increased
dielectric are concerns.
Sheila Smith, Tracor Aerospace Electronics Systems
At 11:20 AM 3/13/97 PST, you wrote:
>
> Does anyone have experience of any failures attributed to
> running PCBs at or above their glass transition temperature?
>
> I heard that this is not a problem and wish to confirm, or
> otherwise.
>
> John
> MBUK
>
>***************************************************************************
>* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
>***************************************************************************
>* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
>* with <subject: subscribe/unsubscribe> and no text in the body. *
>***************************************************************************
>* If you are having a problem with the IPC TechNet forum please contact *
>* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
>***************************************************************************
>
>
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
|
|
