There is nothing wrong with scoring and a proper panelization and 
     scoring/routing can result in major PWB cost savings.
     You just have to determine in advance how the boards will be 
     depanalized in production and design in the required criteria at the 
     PWB level up front.
     If production plans on using equipment to depanel (punch, V-blade, 
     etc.), then you need to know the component placement keep outs 
     required around the edges of the board to clear the blades as well as 
     component height restriction,etc.
     If boards are broken by hand, then DO NOT place any component close to 
     the edge since solder joints will get damaged. As Gary has indicated 
     below, the board dimension is not appropriate for breaking by hand and 
     I don't even know if there is enough room on the board (1/2" X 10") to 
     move components away from the edges for a punch equipment. 
     
     [log in to unmask]
     
     
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
>
>