Dave, at design review stage we decide how boards will be panelized a well
as how in Mfg. they will be depanelized. We use three methods, depanelize
with pizza slicer, depanelize with nibbler, and break apart by hand. Based
on the board design and adjacent components we decide this before the first
run. If manufacturing can show us that our initial decision was not the best
way we would change the process. In 4 yrs. we have only changed four
assemblies. If the rail is .200 we may allow breaking by hand for which we
have a fixture they put the board in and snap the rail off. Anything over
.200 has to use the slicer if it is a scored rail. Score depth and
correctness of the V groove is critical to this being successful.
Dave C.

-----Original Message-----
From: Dave Roach [mailto:[log in to unmask]]
Sent: Friday, July 02, 2004 11:10 AM
To: [log in to unmask]
Subject: [TN] Board depanelizing - scored boards


We build many PCB assemblies in panels that are either tabbed or scored.
We have a "pizza cutter" depanelizer, though the line operators find it
easier to just snap the boards apart in some cases.  A month or so ago, we
(manufacturing engineers) mandated using the pizza cutter for depanelizing
all scored boards, because of the possibility of cracking boards or
components while snapping the boards.  Apparently a few operators
complained to their manufacturing supervisor that this takes longer, so he
decided that they don't have to use the pizza cutter unless we can show why
this is necessary.

I searched the IPC documents, but did not find any information on board
depanelizing.  I searched the TechNet archives and found some threads on
the topic, indicating that snapping scored boards can cause damage, and
some recommended minimum spacing for components from the score lines to
minimize the risk of damage.

Are there any specifications or test reports that may give more information
that we could use to mandate the use of the depanelizer on scored boards?

Dave Roach
Manufacturing Engineer
Trane Global Controls and Contracting
St. Paul, Minnesota

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