Gerald

Punching double sided boards is typical in China. I have also seen punched
four layer and am told that six layer boards are also sometimes punched. I
found it beyond belief that anyone would punch multilayer, but the hole
walls I have seen are not that bad and the damage to the board
(delamination) did not seem to be an issue. I am still uncomfortable with
the concept, but it is probably my personal history at Bell Laboratories.

Best regards

Lee

J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389


----- Original Message -----
From: "Gerald Gagnon" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, March 18, 2006 10:57 AM
Subject: Re: [TN] Die Punching PWBs as opposed to drilling and NC routing


> Joe,
>
> Thanks.
>
> I hope there will be more comments particularly from producers and users
> of
> punched PWBs. Coming from the mainstream, punching seems to be a lost art.
>
> I am concerned about punching multilayers particularly with the newer
> materials that we use today which might not have been evaluated or
> formulated for punching.
>
> Thanks,
>
> Gerry
>
>
> From: Joe Fjelstad <[log in to unmask]>
> Reply-To: TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
> To: [log in to unmask]
> Subject: Re: [TN] Die Punching PWBs as opposed to drilling and NC routing
> Date: Fri, 17 Mar 2006 16:00:16 EST
>
> NC drills are highly versatile and stacking panels provides some economy
> and
> so it will be hard to displace them.
>
> Punching can be fast (all holes at once) but is one at a time and
> depending
> on approach, hole count and feature size the tooling might be costly and
> must
> be amortized over a number of panels to pay for the tool.
>
> Hole quality is not as good making plating more of a challenge if you plan
> on doing double sided PCBs. I have not heard of MLBs being punched
> (except
> when the drills got too dull ;-)
>
> There should also be some concerned about punching small holes on fine
> pitch
> in glass fabric as there would be a higher risk of CAF, however  for
> polymer
> films it is not so much of an issue.
>
> I expect there will be other comments coming.
>
> Joe
>
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