Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Sat, 31 Jan 1998 10:57:41 -0800 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Hi Thad,
Z-axis expansion is probably going to be an issue with this board unless
you use a material with Tg>170 deg. You can also do some things with the
plating to provide the best tensile/elongation strength possible. (Panel
plating, lower amperage, etc.) but the Z-axis expansion is the critical
factor here.
Have a good day,
Sharon
At 05:39 PM 1/30/98 CST, you wrote:
> Currently we are designing a board thicker than normal with small
> holes.
>
> The board is a 10 layer board, 082" thick, and uses 13.5 mil
> drilled/plated holes.
>
> The board is large ~ 13 x 16" in size. It is HASL. During component
> assembly it will see 2 IR processes and a wave. We are specifying
> the board as IPC Class 2. It will be used in high end computer
> product. Reliability is very important.
>
> In light of the above I have several questions for this distinguished
> group:
>
> 1. Considering the 6 to 1 aspect ratio, using conventional FR-4 will
> the design above have reliable plated through holes?
>
> 2. We are considering specifying that the FR-4 be of Tg greater than
> 170 Deg C. The hope is that this will improve hole relaibility. The
> problem is that this will add significant cost to the board. Is it
> necessary to do this?
>
> 3. The design is dense so that we cannot grow the hole significantly.
> We are considering permitting hole breakout of 1 mil, so that the
> holes can be drilled larger. Is this a reliability risk?
>
> 4. Are there other alternatives (not so expensive) to improve hole
> reliability?
>
> I would appreciate any feedback.
>
> Thanks,
>
> [log in to unmask]
>
>################################################################
>TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
>################################################################
>To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in the body:
>To subscribe: SUBSCRIBE TechNet <your full name>
>To unsubscribe: SIGNOFF TechNet
>################################################################
>Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional
information.
>For the technical support contact Dmitriy Sklyar at [log in to unmask] or
847-509-9700 ext.311
>################################################################
>
>
>
>
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################
|
|
|