Jeffrey,

We have some boards that were 0.030 on the web and were almost
impossible to break. 

I see in IPC-2222, Section 5.3.1 there are some guidelines but I don't
see a "chart" of dimensions that are recommended for each of the most
common thichnesses.

Any suggestions?

Phil

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeffrey Bush
Sent: Friday, November 04, 2005 4:51 PM
To: [log in to unmask]
Subject: Re: [TN] V-score depth of new RoHS board materials

We are scoring quite a bit of these - the flexural strength is slightly
higher on the non-dicey systems but we have not seen issues with
standard scores webs - the weights are similar to FR4. A 33% web
thickness is high, we target from 15-25% depending on the pallet config
and assembly needs - 15% is the general target.  A .030" web has a good
strength as the reinforcement is still intact with multiple plies
working against you.


Jeffrey Bush
Director, Quality Assurance and Technical Support

VERMONT CIRCUITS INCORPORATED
  76 Technology Drive - POB 1890
    Brattleboro, Vermont 05302
      Voice: 802.257.4571.21 Fax: 802.257.0011
           http://www.vtcircuits.com
 
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting
Sent: Friday, November 04, 2005 11:44 AM
To: [log in to unmask]
Subject: [TN] V-score depth of new RoHS board materials

Good afternoon,
 
Has anybody started buying boards fab'd using Isola 410 or Polyclad
FR-4-370-HR and had difficulty breaking the boards at the v-score?
 
We have some 0.090 boards that were cut down to 0.030 and were still
difficult to break apart.  Had them reworked to 0.020, but I'm worried
that this may be too thin.
 
Thanks in advance,
 
Phil

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