 
| Subject: | |
| From: | |
| Reply To: | (Leadfree Electronics Assembly Forum) |
| Date: | Tue, 1 Mar 2005 08:31:57 -0000 |
| Content-Type: | text/plain |
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There is no prescribed method or rule, some will depend on the material
you use, the board design and the actual topology of the board.
The only real way you'll find out is to start trying it.
No one is going to or is able to say what will definitely work for you
in your set up and with your products.
I certainly would not totally agree with the 9" dimension statement for
instance.
Regards,
Chris
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Camille Good
Sent: 28 February 2005 19:56
To: [log in to unmask]
Subject: Re: [LF] Maximum PWB Size
Colin,
A seminar I went to last year said that for 0.063-inch
thick PCBs, the PCB will need a metal frame for
support if it is greater than 9 inches in any
dimension.
-Camille
--- "James, Chris" <[log in to unmask]> wrote:
> We still expect equipment capability to be the
> limiting factor on board
> size.
>
> You may need to look a board supports to stop sag.
>
> There are many projects starting or underway looking
> into process
> concerns, the NPL being one.
>
> Regards,
> Chris
>
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]] On Behalf
> Of Colin Weber
> Sent: 28 February 2005 00:08
> To: [log in to unmask]
> Subject: [LF] Maximum PWB Size
>
> Hi Folks,
>
> Can anyone suggest what might be a good guide for
> maximum multilayer
> (4-8
> layers) PWB size
> for Lead Free Processes. ie. Has anyone experienced
> a PCB size
> limitation
> where lead free
> processing raises concern for reliability of the
> boards service life?
>
> I am of the understanding that reliability may be
> poorer for larger
> printed
> circuit boards
> going through the higher temperatures during
> manufacture. Issues like
> warping and plated
> through-holes stress being of particular concern to
> me.
>
>
>
> Regards,
>
> Colin Weber
>
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