Leo,

There are equipment out there (Pizza cutter!!) designed to depanel V-grooved 
board. The V-blade used in those equipment will minimize bending stress 
inflicted on the PCB to minimum.
(BTW,try to reduce the groove web to 0.015" if possible)

Yuen

 ----------
From: TechNet-request
To: Leo Reynolds
Cc: Technet
Subject: Re: ASSY:  Depanelization of SMT Board Assys
Date: Thursday, April 25, 1996 8:37AM

Leo;

We experienced similar problems with a board the same dimensions. When we
investigated the excising methodology we were astonished to find that the
customer was attempting to break the boards away, by hand! Boards with
unsual aspect ratios, must be broken ustilizing a fixture that applys
uniform pressure at the break point. This should reduce the forces that get
transmitted into the board and the componet solder joints.

Regards,

Gary Ferrari
Tech Circuits


At 04:33 PM 4/24/96 -0500, Leo Reynolds wrote:
>We are a contract manufacturer and are currently having trouble with a 1
>1/2" X 10" SMT board assy.  It was designed in a panel of 6, scored for
>eventual break apart and the original scoring left .018" of material in the
>groove.  When we started to break them apart we found we were cracking some
>of the SMT caps.  We've since instructed the PCB mfgr to go to a more
>standard .012" per one engineers recmmendation, but don't have samples yet
>to try.  One of our process engineers attending Nepcon had several 
engineers
>tell him that SMT boards shouldn't be scored at all.
>
>We are trying to determine the best course of action to recommend to our
>customer.  The customers design engineer felt we shouldn't have had a
>problem with the original .018" groove so we may have to put together a 
very
>god case for changing to routing or anyuthing else.
>
>Anyone have any recommendations?
>
>Thanks in advance for your consideration.
>
>Leo Reynolds
>
>